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Sample records for harris dot harris

  1. Women @ Energy: Dot Harris | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    LaDoris (Dot) Harris is the Director of the Office of Economic Impact and Diversity. LaDoris (Dot) Harris is the Director of the Office of Economic Impact and Diversity. LaDoris (Dot) Harris is the Director of the Office of Economic Impact and Diversity. She was nominated by President Obama and confirmed by the U.S. Senate on March 29, 2012. She has served at some of the world's largest firms including General Electric, ABB Service, and Westinghouse Electric Company. Ms. Harris leads the

  2. Director Dot Harris Inspires Girls at DigiGirlz Day Event | Department of

    Office of Environmental Management (EM)

    Energy Director Dot Harris Inspires Girls at DigiGirlz Day Event Director Dot Harris Inspires Girls at DigiGirlz Day Event March 3, 2015 - 4:38pm Addthis Director Harris engages with DigiGirlz (Middle Tennessee High School students) Director Harris engages with DigiGirlz (Middle Tennessee High School students) During the 3rd Annual DigiGirlz Day event held in Nashville, TN on Saturday, February, 28, 2015, Dot Harris, Director of DOE's Office of Economic Impact and Diversity, delivered an

  3. Arno Harris | Open Energy Information

    Open Energy Info (EERE)

    Arno Harris Jump to: navigation, search Name: Arno Harris Place: California Product: Founder and General Manager of EI Solutions (formerly Prevalent Power Inc.) References: Arno...

  4. Chioke B. Harris

    Broader source: Energy.gov [DOE]

    Chioke Harris is an AAAS Science & Technology Policy Fellow placed at the US Department of Energy’s Building Technologies Office in their Emerging Technologies (ET) Program. His current...

  5. Harry A. Atwater - JCAP

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Harry A. Atwater Director and Lead Principal Investigator Email: haa@caltech.edu Dr. Harry Atwater is the Director of JCAP, and the Howard Hughes Professor and Professor of Applied Physics and Materials Science at the California Institute of Technology. As a Director, Dr. Atwater is the lead Principal Investigator responsible for all aspects of the program's management and research. Dr. Atwater received his S.B. (1981), S.M. (1983), and Ph.D. (1987) in Electrical Engineering from the

  6. Harry Weerts | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Harry Weerts, Associate Laboratory Director, Physical Sciences and Engineering Harry Weerts Associate Laboratory Director - Physical Sciences and Engineering Harry Weerts is the Associate Laboratory Director for Physical Sciences and Engineering. He oversees Argonne's interdisciplinary research programs in physics, chemistry, material science and nanotechnology. Weerts was formerly Director of Argonne's High Energy Physics division, and prior to that, a collider physicist at Fermilab, where he

  7. Mr. Harry S. Cohen

    Office of Legacy Management (LM)

    a50b Mr. Harry S. Cohen 2956 Hathaway Road Apartment 1105 ' Richmond, Virginia 23225 Dear Mr. Cohen: ..:: The Department of Energy (DOE), as part of its Formerly Utilized Sites Remedial Action Program (FUSRAP), has reviewed information on the former site of the Virginia-Carolina Chemical Corporation, located.at @I8 Perry Street in Richmond, Virginia, to determine whether It contains residual radioactivity traceable to activities conducted on behalf of the Manhattan Engineer District and the

  8. Dear Mr. Harris,

    Office of Environmental Management (EM)

    1, 2011 Office of the General Counsel, Department of Energy Dear Mr. Harris, The current certification, compliance and enforcement regulations for Commercial Refrigeration Equipment (CRE) "simply makes no sense". The regulations define the basic model as any product that has a different energy use or efficiency level. It does not allow for modeling the performance of our equipment. Our equipment is customized per order and by mixing and matching different combinations we have 118,000

  9. Harry Baumes | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Harry Baumes - Senior Executive Advisor to the Bioenergy Technologies Office and Director, Office of Energy Policy and New Uses, U.S. Department of Agriculture Most Recent Federal ...

  10. Department of Energy's Dot Harris Honored for Blazing Path for Women

    Broader source: Energy.gov [DOE]

    Harris was one of four recipients of the 2014 EmpowHer PathMaker Award, which recognize women who exemplify the characteristics of a PathMaker, one who blazes a path for others to follow and encourages and inspires along the way.

  11. TO : W. B. Harris

    Office of Legacy Management (LM)

    /:' Ofice n/r emordfld%m o UNITED STATE?/ GOVERNMENT TO : W. B. Harris # DATE,: Kay 25, 19jl FROM : T. B. Kle ' 4 SUBJECT: RZSJLTS OF AERCSOL SAMPLING AT U.S. B'JRKALI OF ?4EES XRING VISIT OF XARCH 1, 1951 ' I BRUCZTON, PA. 3~XBOL: HSH:PBK:hnh . Purpose of Visit 1. To obtain aerosol samples during the performanc' ent types of explosibility tests. of several differ- 2; To advise as to the safe handling of material, Results 1. Following are tine results of the average concen before, during and

  12. User:Harris | Open Energy Information

    Open Energy Info (EERE)

    Harris Jump to: navigation, search Name harris Location Houston, Texas Edits 2 Friends User Edits DWC Bot 12006 Retrieved from "http:en.openei.orgwindex.php?titleUser:Harris&o...

  13. Harris Walker | Department of Energy

    Energy Savers [EERE]

    Harris Walker About Us Harris Walker - Communications Specialist, Weatherization and Intergovernmental Program Most Recent Connecticut Weatherization Project Improves Lives, Receives National Recognition May 6 New Year, New Certification Opportunities for Home Energy Workers January 2 How to Save Energy, Money with Home Energy Upgrades November 1

  14. The Honorable LaDoris G. Harris | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    The Honorable LaDoris G. Harris About Us The Honorable LaDoris G. Harris - Director, Office of Economic Impact and Diversity The Honorable LaDoris G. Harris The Honorable La Doris "Dot" Harris brings over 30 years of leadership and management experience as the Director of the Office of Economic Impact and Diversity at the U.S. Department of Energy (DOE). She ensures that minorities and historically underrepresented communities are afforded opportunities to actively participate in the

  15. Harry Frank | Photosynthetic Antenna Research Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Frank Harry Frank Harry Frank Harry Frank Research Affiliate E-mail: harry.frank@uconn.edu Phone: 860.486.2844 Fax: 860.486.6558 Website: University of Connecticut Research Affiliate Dr. Frank's research focus is on carotenoids, a class of biological pigments. This research includes the roles carotenoids play in photosynthesis and how carotenoids carry out those roles. He employs various techniques, including X-ray and electron diffraction, nuclear magnetic resonance (NMR), absorption and

  16. Women @ Energy: Deborah Harris | Department of Energy

    Energy Savers [EERE]

    Deborah Harris Women @ Energy: Deborah Harris March 11, 2013 - 5:33pm Addthis Women @ Energy: Deborah Harris Dr. Deborah Harris's current research interest is in the field of neutrino interactions and oscillations. Her work at Fermilab began with NuMI, the beamline that provides neutrinos to the MINERvA experiment, focusing on the beamline monitoring system. After working on both NOvA and MINOS oscillation experiments she realized that both of these experiments would need a better understanding

  17. North Carolina Nuclear Profile - Harris

    U.S. Energy Information Administration (EIA) Indexed Site

    Harris" "Unit","Summer capacity (mw)","Net generation (thousand mwh)","Summer capacity factor (percent)","Type","Commercial operation date","License expiration date" 1,900,"7,081",89.8,"PWR","application/vnd.ms-excel","application/vnd.ms-excel" ,900,"7,081",89.8 "Data for 2010" "PWR = Pressurized Light

  18. A. Paul Alivisatos and Harry Atwater

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Paul Alivisatos and Harry Atwater University of California, Berkeley and Caltech Photovoltaic performance of ultra-small PbSe quantum dots Achievement: We developed a synthesis for ultra-small, strongly con ned PbSe nanocrystals 1-3nm in diameter, allowing absorption to be tuned across the entire visible spectrum. A larger bandgap in smaller particles leads to higher open-circuit voltages (~0.6V) and increased overall efficiency (~3.5%) compared to previously reported photovoltaic devices of

  19. Scott Blake Harris | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    Scott Blake Harris - Former General Counsel Scott Blake Harris served as the General Counsel for the Department of Energy. Most Recent Getting Smarter About the Smart Grid October 13 Enforcing Energy-Efficiency Standards September 13 The Power of Information July 21

  20. Harry Bolson | Photosynthetic Antenna Research Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Bolson Harry Bolson placeholder image Harry Bolson Alumnus E-mail: hbbholson@wustl.edu Website: Washington University in St. Louis Mr. Bolson completed the Certificate in Renewable Energy & the Environment and graduated from Washington University in St. Louis in 2014. He is now a procurement agent with The Boeing Company. Alumni

  1. Comments by Mary Celeste Harris on the Emergency Operation of...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Mary Celeste Harris on the Emergency Operation of Mirant's Potomac River Generating Station. ... Celeste Harris Related to District of Columbia Public Service Commission Docket No. ...

  2. Harry E Mynick | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Harry E Mynick Principal Research Physicist, Plasma Physics Laboratory. Dr. Mynick is a Principal Research Physicist in the Theory Department at the Princeton Plasma Physics Laboratory (PPPL). Mynick is the author of more than 120 scientific papers. His research interests are in plasma physics, in energy and environmental studies, and in artificial intelligence. Within plasma physics, his principal areas of technical expertise are in plasma transport, particularly in 3-dimensional toroidal

  3. Department of Energy Response to Correspondence from Mary Celeste Harris

    Energy Savers [EERE]

    Related to District of Columbia Public Service Commission Docket No. EO-05-01 | Department of Energy Mary Celeste Harris Related to District of Columbia Public Service Commission Docket No. EO-05-01 Department of Energy Response to Correspondence from Mary Celeste Harris Related to District of Columbia Public Service Commission Docket No. EO-05-01 Docket No. EO-05-01: Department of Energy response to correspondence from Mary Celeste Harris related to District of Columbia Public Service

  4. Harris County, Georgia: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Harris County, Georgia Hamilton, Georgia Pine Mountain, Georgia Shiloh, Georgia Waverly Hall, Georgia West Point, Georgia Retrieved from "http:en.openei.orgw...

  5. COLLOQUIUM: Who Will Save the Tokamak - Harry Potter, Arnold...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    COLLOQUIUM: Who Will Save the Tokamak - Harry Potter, Arnold Schwarzenegger, Shaquille O'Neal, or Donald Trump? Professor Jeffrey Freidberg Massachusetts Institute of Technology ...

  6. Harris Hill, New York: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Hide Map This article is a stub. You can help OpenEI by expanding it. Harris Hill is a census-designated place in Erie County, New York.1 References US...

  7. Harris County- Green Building Policy for County Buildings

    Broader source: Energy.gov [DOE]

    The Harris County Facilities and Property Management (FPM) Division also requires all county buildings to meet minimum energy efficiency and sustainability measures, as described in the Best Gree...

  8. Summer 2012 Intern Project- Rachel Harris | Center for Energy Efficient

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Materials Rachel Harris INVESTIGATING DEGRADATION IN POLYMER SOLAR CELLS Rachel Harris UC Santa Barbara Mentor: Chris Liman Faculty Advisor: Michael Chabynic Department: Materials Performance degradation is a common problem faced by polymer photovoltaic cells. It is necessary to understand the origins of degradation processes in order to relieve the issue and increase the technology's potential for becoming a viable renewable energy resource. In this study, organic photovoltaic devices were

  9. Harry Potter, Oxford and Nuclear Energy | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    Assistant Secretary Dr. Peter Lyons meets with students on the Oxford University Campus in the same room where scenes from the Harry Potter films were filmed. Assistant Secretary Dr. Peter Lyons meets with students on the Oxford University Campus in the same room where scenes from the Harry Potter films were filmed. Karissa Marcum Public Affairs Specialist, Office of Public Affairs Dr. Peter Lyons, the Assistant Secretary for Nuclear Energy at the Energy Department and the U.S. government's

  10. Magoon v. Harris, 46 Vt. 264, 269 (1863) | Open Energy Information

    Open Energy Info (EERE)

    Magoon v. Harris, 46 Vt. 264, 269 (1863) Jump to: navigation, search OpenEI Reference LibraryAdd to library Legal CaseHearing: Magoon v. Harris, 46 Vt. 264, 269 (1863)Legal...

  11. Harris Power Earns Jefferson Lab's Top Small Business Award for 2010 |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jefferson Lab Harris Power Earns Jefferson Lab's Top Small Business Award for 2010 NEWPORT NEWS, Va., April 26, 2011 - Harris Power & Equipment, based in Yorktown, has been recognized as Jefferson Lab's Outstanding Small Business Subcontractor of the Year for 2010. R. Dudley Harris, company president, and several Harris employees who regularly carry out contract work at Jefferson Lab, attended an awards ceremony at the laboratory on April 21. He accepted the award, saying, "Being

  12. Cristal Jones-Harris | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    Cristal Jones-Harris Albert Einstein Distinguished Educator Fellowship (AEF) Program Einstein Fellowship Home Eligibility Benefits Obligations How to Apply Key Dates Frequently Asked Questions Fellows Central Current Fellows Official AEF Logos Contact WDTS Home Current Fellows Cristal Jones-Harris Print Text Size: A A A FeedbackShare Page Cristal Jones-Harris Fellowship Placement: National Aeronautics and Space Administration Hometown: Sandy Springs, GA Cristal Jones-Harris, Ed. D., is a teacher

  13. TO. TO. , W. B; Harris, Chief, Industrial Hygiene'Branch DA , W. B; Harris, Chief, Industrial Hygiene'Branch DA

    Office of Legacy Management (LM)

    ~~~~;.Offi~~~~~~~~~~~ ,/-; l UNITED STh , :__ .~. :__ .~. , , TO. TO. , W. B; Harris, Chief, Industrial Hygiene'Branch DA , W. B; Harris, Chief, Industrial Hygiene'Branch DA Health and Safet Division pa& 1 Ps B.- Klevin :mL -y!yG hMBOL: HSH:PBK hMBOL: HSH:PBK : 1. Purpose of Visit >.. a. To study operations planned by~Bu.reau of Ea: factors for Be, II, thorium, zirconium, etc, i b. ,'To explain to Bureauof Mines' personnel tl in handling any of the aforementioned mate] 2. Scope of Work

  14. COLLOQUIUM: Who Will Save the Tokamak - Harry Potter, Arnold

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Schwarzenegger, Shaquille O'Neal, or Donald Trump? | Princeton Plasma Physics Lab January 20, 2015, 1:30pm to 3:00pm Colloquia MBG Auditorium COLLOQUIUM: Who Will Save the Tokamak - Harry Potter, Arnold Schwarzenegger, Shaquille O'Neal, or Donald Trump? Professor Jeffrey Freidberg Massachusetts Institute of Technology Presentation: File Presentation This paper attempts to bridge the gap between tokamak reactor design and plasma physics. The analysis demonstrates that the overall design of a

  15. Comments by Mary Celeste Harris on the Emergency Operation of Mirant's

    Energy Savers [EERE]

    Potomac River Generating Station. | Department of Energy Mary Celeste Harris on the Emergency Operation of Mirant's Potomac River Generating Station. Comments by Mary Celeste Harris on the Emergency Operation of Mirant's Potomac River Generating Station. Docket No. EO-05-01: Comments by Mary Celeste Harris on the Emergency Operation of Mirant's Potomac River Generating Station. "I am writing in response to your order of December 20, 2005, declaring the emergency operation of Mirant's

  16. Microsoft PowerPoint - 13 DOE PM Workshop UPF Presentation revised - Harry

    Office of Environmental Management (EM)

    Peters [Compatibility Mode] | Department of Energy 3 DOE PM Workshop UPF Presentation revised - Harry Peters [Compatibility Mode] Microsoft PowerPoint - 13 DOE PM Workshop UPF Presentation revised - Harry Peters [Compatibility Mode] PDF icon Microsoft PowerPoint - 13 DOE PM Workshop UPF Presentation revised - Harry Peters [Compatibility Mode] More Documents & Publications The Process, Methods and Tool Used To Integrate Safety During Design of a Category 2 Nuclear Facility Independent

  17. TO I Ppi B. Harris, Chief, Industrial Rygiene Branah

    Office of Legacy Management (LM)

    Ppi B. Harris, Chief, Industrial Rygiene Branah DATE: .' hpt Health and Safe i-?iSiOll FROM .t A. 3. Breslin 8v SUBJECT: URBHNad ROD DR&RG,TEST AILTWYCKoFF STEZL COO SYMBOL: RSHG%JB:~O On September 6, the m iter accompanied M re Fe Stroke to the Steel Co. in Bewark to witness the trial drawing of l-1/2 i diameter uranium rods* !l'w rods, about four feet in length, were used in the test. just dipped in an 6% solution of hot sulfurio acid, rinsed and ooated in a hot Ca(OH)2 bathe !fhey were D

  18. 4 Questions for a Better Buildings Case Competition Student Participant: Harry Bergmann

    Broader source: Energy.gov [DOE]

    Meet Harry Bergmann, recent graduate of the University of California at Santa Barbara find out how the Better Buildings Case Competition helped him prepare for his new career in the clean energy sector.

  19. Microsoft Word - ex parte memo deLaski Harris.doc

    Office of Environmental Management (EM)

    On Friday, November 12 th , I spoke with DOE General Counsel Scott Blake Harris by telephone. This conversation concerned what process DOE might use for completing the new test method for residential refrigerators in light of concerns raised by the Association of Home Appliance Manufacturers.

  20. Off-shelf portion of Harris delta: a reexamination of downdip Woodbine-Eagle Ford

    SciTech Connect (OSTI)

    Porter, M.

    1989-03-01

    This study relates the Eagle Ford-equivalent Harris delta north of the Stuart City shelf edge with the downdip Woodbine-Eagle Ford section south of that shelf edge. Together, they comprised one large deltaic complex that divided into two major lobes at an avulsion site near Anderson County. One lobe prograded southwestward toward Kurten field in Brazos County; the other (now partly eroded) prograded southeastward beside the low-lying Sabine (uplift) landmass into Polk County. The Polk County lobe crossed the Stuart City shelf edge in the Seven Oaks-Hortense field area and continued to prograde southward into deeper and higher energy water. Such an environment caused this off-shelf Harris delta to oversteepen, resulting in frequent slumps and gravity flows that deposited debris-flow and turbidite sands along with predominantly fine-grained prodelta sediments. More familiar deltaic facies (outer fringe) are present in the uppermost section. Numerous structural and stratigraphic maps and cross sections illustrate the progradation of the downdip Harris delta and its features. The progradation was arrested for a time by deeper water at the older and more precipitous Sligo shelf edge. This progradational hiatus is recorded by a relatively strong reflection that separates two seismic sequences. The younger, onlapping sequence appears to represent continued Harris delta sedimentation. Among the interesting features mapped seismically and/or geologically are mounded reflections that represent the largest slumping events, thickness anomalies associated with the carbonate substrate, and erosional( ) channels at the section top. These off-shelf Harris delta deposits appear to interfinger laterally with a genetically different eastern (Tuscaloosa ) sequence in Tyler and Jasper Counties.

  1. Off-shelf portion of Harris delta: Reexamination of downdip Woodbine-Eagle Ford

    SciTech Connect (OSTI)

    Porter, M.H. ); Van Siclen, D.C.; Sheriff, R.E. )

    1989-09-01

    This study related the Eagle Ford equivalent Harris delta north of the Stuart City shelf edge with downdip Woodbine-Eagle Ford section south of that shelf edge. Together, they comprised one large deltaic complex that divided into two major lobes at an avulsion site near Anderson County, Texas. One lobe prograded southwestward toward Kurten field in Brazos County, the other (now partly eroded) prograded southeastward beside the low-lying Sabine (uplift) landmass into Polk County. The Polk County lobe crossed the Stuart City shelf edge in the Seven Oaks-Hortense field area, and continued to prograde southward into deeper and higher energy water. Such an environment caused this off-shelf Harris delta to oversteepen, resulting in frequent slumps and gravity flows that deposited debris-flow and turbidite sands along with predominantly fine-grained prodelta sediments. More familiar deltaic facies (outer fringe) are present in the uppermost section. Numerous structural and stratigraphic maps and cross sections illustrate the progradation of the downdip Harris delta and its features. The progradation was arrested for a time by deeper water at the older and more precipitous Sligo shelf edge. This progradational hiatus is recorded by a relatively strong reflection that separates two seismic sequences. The younger onlapping sequence appears to represent continued Harris delta sedimentation. among the interesting features mapped seismically and/or geologically are: mounded reflections that represent the largest slumping events, thickness anomalies associated with the carbonate substrate, and erosional( ) channels at the section top. These off-shelf Harris delta deposits appear to interfinger laterally with a genetically different eastern (Tuscaloosa ) sequence in Tyler and Jasper Counties.

  2. Harry S. Truman - Hanford Site

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of 1945, the United States was still fighting in World War II against the nation of Japan. Having been told about the successful Trinity Test of an atomic bomb, President...

  3. Savannah Harris | Savannah River Ecology Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    at Heggies Rock and Burks Mountain in Georgia, which integrated concepts from geology, soil science, and biology. Savannah enjoys spending time outdoors, and especially going...

  4. Fossil Energy Acting Assistant Secretary Recognized at Black...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Addthis Director Dot Harris presents Chris Smith, Principal Deputy Assistant Secretary and ... Photo Credit: Nancy Jo Brown106FOTO Director Dot Harris presents Chris Smith, Principal ...

  5. A Conversation With Tribal Leaders in Denver | Department of...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    of the Rocky Flats site following the Tribal Leader Dialogue in Denver on Tuesday. Dot Harris Dot Harris Director, Office of Economic Impact and Diversity Engaging with the...

  6. IDC Integrated Master Plan. Clifford, David J.; Harris, James...

    Office of Scientific and Technical Information (OSTI)

    IDC system. The IMP and the associate Integrated Master Schedule (IMS) are used for planning, scheduling, executing, and tracking the project technical work efforts. REVISIONS...

  7. Harris County- Property Tax Abatement for Green Commercial Buildings

    Broader source: Energy.gov [DOE]

    This type of tax abatement may be sought by an applicant of the County’s standard economic development tax abatement, or as a stand-alone tax abatement. When an applicant seeks only a LEED Certif...

  8. EA-1769: Battleground Energy Recovery Project, Harris County, Texas

    Broader source: Energy.gov [DOE]

    This EA evaluates the environmental impacts of a proposal to provide $1.94 million in cost-shared funding to the Houston Advanced Research Center for the Battleground Energy Recovery Project, which would produce 8 megawatts of electricity from high pressure steam generated by capturing heat that is currently lost at the Clean Harbors Deer Park facility. The proposed project was selected by the DOE's Office of Energy Efficiency and Renewable Energy to advance research and demonstration of energy efficiency and renewable energy technologies.

  9. Harris County, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Power Technology Inc Power Tube Inc RRI Energy Inc formerly known as Reliant Energy Inc Red River Biodiesel Ltd Reliant Energy Ridge Energy Storage and Grid Services LP Simbol...

  10. Workplace Charging Challenge Partner: Harris Civil Engineers, LLC

    Broader source: Energy.gov [DOE]

    Since the late 1990s, Portland General Electric (PGE) has offered plug-in electric vehicle (PEV) charging for its employees. With the advent of the modern Level 2 and DC Quick-Charging standards,...

  11. Pressure Relief Valves Harris, S. [Villanova University, Villanova...

    Office of Scientific and Technical Information (OSTI)

    Gross, R. Exida LLC, Sellersville PA, (United States); Goble, W Savannah River Nuclear Solutions (SRNS), Aiken, SC (United States); Bukowski, J Savannah River Site...

  12. Upholding Dr. King's Dream and Inspiring the Next Generation...

    Broader source: Energy.gov (indexed) [DOE]

    The kids were also able to meet science, technology, engineering and math professionals who volunteered their time to engage more students in STEM fields. Director Dot Harris, who ...

  13. Native American Students in STEM Fields: A Critical Need for our Country

    Broader source: Energy.gov [DOE]

    The Office of Economic Impact and Diversity's Dot Harris recently met with youth from Tribal Nations around the U.S. to discuss the benefits of STEM education.

  14. Mickey Leland Energy Fellowship Seeking Underrepresented Students...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Director Dot Harris (second from left) were Marlene Kaplan, the Deputy Director of Education and director of EPP, National Oceanic and Atmospheric Administration, Claudia...

  15. Applications are Open for YOU to Join the 2013 Class of the Minority...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Director Dot Harris (second from left) were Marlene Kaplan, the Deputy Director of Education and director of EPP, National Oceanic and Atmospheric Administration, Claudia...

  16. Statement on the Eighth Anniversary of the 9/11 Attacks | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    National Day of Remembrance Karl Fraiser, a member of the Savannah River Special Emphasis Planning Committee, meets with Dot Harris at the site's Women's Equality Day Celebration. ...

  17. Leadership | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Leadership Leadership The Honorable LaDoris G. Harris Director, Office of Economic Impact and Diversity The Honorable La Doris "Dot" Harris brings over 30 years of management and leadership experience as the Director of the Office of Economic Impact and Diversity at the U.S. Department of Energy (DOE). She ensures that minorities and historically underrepresented communities are afforded opportunities to fully participate in the Department's programs. More about Dot Harris Andre H.

  18. National Energy Action Month Takes Energy Department Officials...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    10 W. MLK Blvd. Chattanooga, TN WHEN 9:30 AM (EST), Monday, October 20, 2014 WHO Dot Harris, Director, Office of Economic Impact and Diversity WHAT Keynote remarks at the...

  19. Blog Archive | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    time to engage and empower the next generation of girls to rise up as leaders of our democracy and economy. March 1, 2013 Director Dot Harris spoke with over 330 students about...

  20. National Air & Space Intelligence Center Holds Program About Empowering

    Broader source: Energy.gov (indexed) [DOE]

    Women in the Workplace | Department of Energy Dot Harris, Director of the Office of Economic Impact and Diversity, speaks with Aurea Rivera, President and CEO of Imagineering Results Analysis Corp., Kathleen Tucker, Director of the Information Exploitation Squadron, Global Exploitation Intelligence Group, NAISC, and Ann Carbonell, Chief of the National Geospatial Intelligence Agency Support Team in September 2013. Photo by National Air and Space Intelligence Center. Dot Harris, Director of

  1. Why 3D Printers Might Create the Next Robotic Champion | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy Why 3D Printers Might Create the Next Robotic Champion Why 3D Printers Might Create the Next Robotic Champion December 11, 2013 - 4:18pm Addthis As the nation's premier research laboratory, Oak Ridge National Laboratory is one of the world's most capable resources for transforming the next generation of scientific discovery into solutions for rebuilding and revitalizing America's manufacturing industries, with tools like 3D printers. Dot Harris Dot Harris Director, Office of Economic

  2. A Cornerstone of Our Energy Future: Women | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    A Cornerstone of Our Energy Future: Women A Cornerstone of Our Energy Future: Women March 19, 2014 - 1:47pm Addthis Secretary of Energy Ernest Moniz with The Honorable Dot Harris, Director of the Energy Department's Office of Economic Impact and Diversity (far left), and Sandra Guzman, award winning multimedia journalist, at the Minorities in Energy launch event. | Photo by the Energy Department. Secretary of Energy Ernest Moniz with The Honorable Dot Harris, Director of the Energy Department's

  3. Here to Serve | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Here to Serve Here to Serve May 11, 2012 - 8:53am Addthis Dot Harris Dot Harris Director, Office of Economic Impact and Diversity It is a pleasure to join the Administration as the Director of the Office of Economic Impact and Diversity here at the Department of Energy. When President Obama nominated me for this position, I immediately recognized the vital importance of the work that this office does. From assisting small businesses to supporting minority serving institutions to enhancing the

  4. This is our Future: Secretary Chu and Senator Udall Speak on Attracting

    Energy Savers [EERE]

    Women and Minorities to the Wind Industry | Department of Energy This is our Future: Secretary Chu and Senator Udall Speak on Attracting Women and Minorities to the Wind Industry This is our Future: Secretary Chu and Senator Udall Speak on Attracting Women and Minorities to the Wind Industry December 21, 2012 - 12:15pm Addthis Dot Harris Dot Harris Director, Office of Economic Impact and Diversity This past Wednesday, the Energy Department livestreamed a conversation between Energy Secretary

  5. Why 3D Printers Might Create the Next Robotic Champion | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy Why 3D Printers Might Create the Next Robotic Champion Why 3D Printers Might Create the Next Robotic Champion December 11, 2013 - 4:18pm Addthis As the nation's premier research laboratory, Oak Ridge National Laboratory is one of the world's most capable resources for transforming the next generation of scientific discovery into solutions for rebuilding and revitalizing America's manufacturing industries, with tools like 3D printers. Dot Harris Dot Harris Director, Office of Economic

  6. Celebrating Small Business Week at the Energy Department | Department of

    Energy Savers [EERE]

    Energy Small Business Week at the Energy Department Celebrating Small Business Week at the Energy Department June 21, 2013 - 5:23pm Addthis Energy Department Small Business Partner Success Stories Dot Harris Dot Harris Director, Office of Economic Impact and Diversity Small Business Resources Take a look at our Small Businesses 101 page for more resources. This week as the nation celebrates the 50th annual Small Business Week, we celebrate our 'small business first' philosophy and policy at

  7. Making STEM Personal: Introducing the Women @ Energy Series | Department of

    Office of Environmental Management (EM)

    Energy STEM Personal: Introducing the Women @ Energy Series Making STEM Personal: Introducing the Women @ Energy Series March 18, 2013 - 11:53am Addthis Graphic by <a href="http://energy.gov/diversity/listings/women-energy">Sarah Gerrity</a>. Graphic by Sarah Gerrity. Dot Harris Dot Harris Director, Office of Economic Impact and Diversity Check Us Out on Pinterest Get inspired! Check out our Women @ Energy Pinboard . Occupations in Science, Technology, Engineering and

  8. How Small Businesses Support the Department of Energy | Department of

    Office of Environmental Management (EM)

    Energy Small Businesses Support the Department of Energy How Small Businesses Support the Department of Energy July 23, 2013 - 4:02pm Addthis Energy Department Small Business Partner Success Stories Dot Harris Dot Harris Director, Office of Economic Impact and Diversity What are the key facts? Almost half of the subcontracts that come from our Management and Operations contractors and other large prime contractors go to small businesses. In Fiscal Year 2012, $1.3 billion prime contracts and

  9. History of Women at the Energy Department | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Women at the Energy Department History of Women at the Energy Department March 27, 2014 - 5:55pm Addthis Dot Harris Dot Harris Director, Office of Economic Impact and Diversity Terry Fehner Terry Fehner Historian, Federal Preservation Officer Women have been making a significant impact in science, technology, engineering and mathematics (STEM) fields for centuries. Join the Energy Department in celebrating Women's History Month by viewing this timeline for a glimpse of the accomplishments of

  10. Wrapping Up: Our Conversation on Increasing Diversity in STEM Education and

    Broader source: Energy.gov (indexed) [DOE]

    the Workforce | Department of Energy Watch our science and tech experts answer questions and share advice on STEM Education and Careers. Dot Harris Dot Harris Director, Office of Economic Impact and Diversity Where Can I Learn More? Visit diversity.energy.gov for more on the Department's efforts to support minority participation in STEM fields. The national alarm has been sounded. While industry demand for science, technology, engineering and math (STEM) professionals is building at a

  11. A Minority Serving Institution Leads the Way in Better Buildings |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy A Minority Serving Institution Leads the Way in Better Buildings A Minority Serving Institution Leads the Way in Better Buildings July 5, 2012 - 6:06pm Addthis Secretary Chu visits Delaware State University to commemorate the school's efforts with the Better Buildings Initiative. Secretary Chu visits Delaware State University to commemorate the school's efforts with the Better Buildings Initiative. Dot Harris Dot Harris Director, Office of Economic Impact and Diversity

  12. Research Affiliates | Photosynthetic Antenna Research Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Engel Gregory Engel Research Affiliate E-mail: gsengel@uchicago.edu Phone: 773.834.0818 Harry Frank Harry Frank Research Affiliate E-mail: harry.frank@uconn.edu Phone: 860.486.2844...

  13. Microsoft PowerPoint - 13 DOE PM Workshop UPF Presentation revised...

    Office of Environmental Management (EM)

    3 DOE PM Workshop UPF Presentation revised - Harry Peters Compatibility Mode Microsoft PowerPoint - 13 DOE PM Workshop UPF Presentation revised - Harry Peters Compatibility...

  14. Portsmouth Site Delivers First Radioactive Waste Shipment to...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Melissa Dunsieth, Randy Barr, Rick Williams, Janet Harris, Maureen Fischels, Cecil ... Melissa Dunsieth, Randy Barr, Rick Williams, Janet Harris, Maureen Fischels, Cecil ...

  15. Before the Senate Energy and Natural Resources Committee | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Scott Blake Harris, Nominee for General Counsel Subject: Nomination Hearing PDF icon 4-23-09FinalNominationTestimony(Harris).pdf More Documents & Publications Before the Senate...

  16. Management Council | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Illinois at Urbana-Champaign Vice Chancellor for Research Professor of Physics Web Site Harry Weerts Harry Weerts Argonne National Laboratory Interim Associate Laboratory Director...

  17. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... 2004 TO 2014 Harris, S. ; Gross, R. ; Watson, H. Full Text Available February 2015 ... 2004 TO 2014 Harris, S. ; Gross, R. ; Watson, H. Full Text Available February 2015 ...

  18. Hanford Selects Small Business for $99M Contract | Department of Energy

    Office of Environmental Management (EM)

    Selects Small Business for $99M Contract Hanford Selects Small Business for $99M Contract June 8, 2012 - 4:34pm Addthis Hanford Selects Small Business for $99M Contract Dot Harris Dot Harris Director, Office of Economic Impact and Diversity Small businesses are the backbone of our economy, employing half of all workers in America and creating two out of every three new jobs in the U.S. Today, our Hanford Site awarded a $99 million contract (approximate value) to a minority-owned, women-owned,

  19. In DC and Around the Nation: Join the National Day of Service on Saturday,

    Office of Environmental Management (EM)

    January 19, 2013 | Department of Energy In DC and Around the Nation: Join the National Day of Service on Saturday, January 19, 2013 In DC and Around the Nation: Join the National Day of Service on Saturday, January 19, 2013 January 16, 2013 - 9:22am Addthis Dot Harris Dot Harris Director, Office of Economic Impact and Diversity Americans in all 50 states can honor the legacy of Dr. Martin Luther King, Jr., though living out his values of service, care for your neighbor, and social justice.

  20. Quantum Dots: Theory

    SciTech Connect (OSTI)

    Vukmirovic, Nenad; Wang, Lin-Wang

    2009-11-10

    This review covers the description of the methodologies typically used for the calculation of the electronic structure of self-assembled and colloidal quantum dots. These are illustrated by the results of their application to a selected set of physical effects in quantum dots.

  1. EA-1769: Final Environmental Assessment and Finding of No Significant Impact

    Broader source: Energy.gov [DOE]

    Houston Advanced Research Center, Battleground Energy Recovery Project, Deer Park, Harris County, Texas (October 2011)

  2. Sandia Energy - 'Giant' Nanocrystal Quantum Dots

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    'Giant' Nanocrystal Quantum Dots Home Energy Research EFRCs Solid-State Lighting Science EFRC 'Giant' Nanocrystal Quantum Dots 'Giant' Nanocrystal Quantum DotsTara...

  3. DOT specification packages evaluation

    SciTech Connect (OSTI)

    Ratledge, J.E.; Rawl, R.R. )

    1991-01-01

    During the late 1960s and early 1970s, the Department of Transportation (DOT) specification package system was implemented to serve as a useful and equivalent alternative to the Nuclear Regulatory Commission (NRC) and the Bureau of Explosives approval systems for Type B and fissile radioactive material package designs. When a package design was used by a large number of organizations, the package design was added to the DOT regulations as a specification package authorized for use by any shipper. In the mid-1970s, the NRC revised its package design certification system to the one in use today. This paper reports that, while the NRC and DOT transportation regulations have evolved over the years, the DOT specification package designs have remained largely unchanged. Questions have been raised as to whether these designs meet the current and proposed regulations. In order to enable the NRC and DOT to develop a regulatory analysis that will support appropriate action regarding the specification packages, a study is being performed to compile all available design, testing, and analysis information on these packages.

  4. 'Giant' Nanocrystal Quantum Dots

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    'Giant' Nanocrystal Quantum Dots - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs

  5. Browse by Discipline -- E-print Network Subject Pathways: Environmenta...

    Office of Scientific and Technical Information (OSTI)

    I J K L M N O P Q R S T U V W X Y Z Kerekes, Tamas (Tamas Kerekes) - Department of Energy Technology, Aalborg University Kwatny, Harry G. (Harry G. Kwatny) - Department of ...

  6. CX-004115: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Harris County North Bayou Central PlantCX(s) Applied: B5.1Date: 09/24/2010Location(s): Harris County, TexasOffice(s): Energy Efficiency and Renewable Energy, Golden Field Office

  7. CX-002864: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Harris County North Bayou Central PlantCX(s) Applied: B5.1Date: 07/01/2010Location(s): Harris County, TexasOffice(s): Energy Efficiency and Renewable Energy, Golden Field Office

  8. Requests for Information | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Center Attn: AMSAM-TMD-SD, Bldg 5417 Contact: Mr. William S. Harris, Jr. Redstone Arsenal, AL 35898-5000 (256) 876-1786 E-mail to William Harris U.S. Navy and Marine Corps...

  9. Shiny quantum dots brighten future of solar cells

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Shiny quantum dots brighten future of solar cells Shiny quantum dots brighten future of solar ... dots can be applied in solar energy by helping more efficiently harvest sunlight. ...

  10. Promising future of quantum dots explored in conference

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Promising future of quantum dots explored Promising future of quantum dots explored in conference Researchers are gathering to reflect on two decades of quantum dot research at a...

  11. Nanoscale engineering boosts performance of quantum dot light...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Quantum dot light emitting diodes Nanoscale engineering boosts performance of quantum dot light emitting diodes Quantum dots are nano-sized semiconductor particles whose emission...

  12. An in-situ TEM liquid cell for imaging electrode/electrolyte...

    Office of Scientific and Technical Information (OSTI)

    electrodeelectrolyte interactions. Abstract not provided. Authors: Leenheer, Andrew Jay ; Jungjohann, Katherine Leigh ; Zavadil, Kevin R. ; Sullivan, John P 1 ; Harris,...

  13. Interested Parties- Patrick Murphy

    Broader source: Energy.gov [DOE]

    S. Harris, Economic Recovery Advisor to Secretary Chu, reported contact with a lobbyists from the Free Flow Power Corporation.

  14. Light-Material Interactions in Energy Conversion - Energy Frontier Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Center (LMI-EFRC) - Harry Atwater Associate Director Harry Atwater Harry Atwater, Howard Hughes Professor and Professor of Applied Physics and Materials Science; Director, Joint Center for Articificial Photosynthesis California Institute of Technology Professor Harry Atwater is the Howard Hughes Professor of Applied Physics and Materials Science at the California Institute of Technology. Professor Atwater currently serves as Director of the Joint Center for Artificial Photosynthesis. He

  15. 15.10.5 ECS Atwater - JCAP

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    JCAP's Harry Atwater on Critical Energy Issues (ECS Podcast) JCAP Director Harry Atwater in conversation with the Electrochemical Society's Executive Director Roque Calvo on the eve of the fifth international ECS Electrochemical Energy Summit. Related Link: ECS Blog (http://www.ecsblog.org/harry-atwater-on-critical-energy-issues/)

  16. 15.10.5 RH ECS Atwater - JCAP

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    JCAP's Harry Atwater on Critical Energy Issues (ECS Podcast) JCAP Director Harry Atwater in conversation with the Electrochemical Society's Executive Director Roque Calvo on the eve of the fifth international ECS Electrochemical Energy Summit. Related Link: ECS Blog (http://www.ecsblog.org/harry-atwater-on-critical-energy-issues/)

  17. Nontoxic quantum dot research improves solar cells

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    reported for any quantum dot solar cell," said Hunter McDaniel. Record power-conversion efficiency at Los Alamos from quantum-dot sensitized photovoltaics LOS ALAMOS, N.M., Dec....

  18. What the Blank Makes Quantum Dots Blink?

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    What the Blank Makes Quantum Dots Blink? What the Blank Makes Quantum Dots Blink? Calculations confirm that surface flaws are behind fluorescence intermittency in silicon nanocrystals June 15, 2015 Contact: Margie Wylie, mwylie@lbl.gov, +1 510 486 7421 Quantum dots are semiconductors just a few nanometers in diameter that can glow Quantum dots (shown here dissolved in liquid under ultraviolet light) offer tantalizing prospects for new technologies if scientists can stop them blinking. (Photo by

  19. Nontoxic quantum dot research improves solar cells

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nontoxic quantum dot research improves solar cells Nontoxic quantum dot research improves solar cells Solar cells made with low-cost, nontoxic copper-based quantum dots can achieve unprecedented longevity and efficiency, according to a study by LANL and Sharp Corporation. December 10, 2013 Hunter McDaniel, Los Alamos National Laboratory postdoctoral researcher, works in the laboratory developing next-generation quantum dots that could revolutionize photovoltaic technology. Hunter McDaniel, Los

  20. Light-Material Interactions in Energy Conversion - Energy Frontier Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Center (LMI-EFRC) Lectures & Tutorials Lectures from the LMI-EFRC "New Approaches to Full Spectrum Solar Energy Conversion" Webinar, September 3, 2015, Caltech Harry A. Atwater Quantum Dot Luminescent Concentrators Paul Alivisatos, Lawrence Berkeley National Laboratory John Rogers Control of Thermal Radiation Using Photonic Structures for Energy Applications Shanhui Fan, Stanford University Eli Yablonovitch Printing Functional Materials Jennifer Lewis, Harvard lmi logo Panel

  1. Microsoft Word - 2015webinar_flyer3.docx

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Program 8:30-9:00 am Paul Alivisatos, LBL Quantum Dot Luminescent Concentrators 9:00-9:30 am Shanhui Fan, Stanford Control of Thermal Radiation Using Photonic Structures for Energy Applications 9:30-10:00 am Jennifer Lewis, Harvard Printing Functional Materials 10:00-10:30 am Panel Discussion: Enabling Science for Full Spectrum Conversion Panelists Harry Atwater, Caltech; Jennifer Dionne, Stanford; Eli Yablonovitch, LBL Moderated by Ralph Nuzzo, LMI Director The Light-Material Interactions in

  2. Intentionally Including - Engaging Minorities in Physics Careers |

    Office of Environmental Management (EM)

    Department of Energy Intentionally Including - Engaging Minorities in Physics Careers Intentionally Including - Engaging Minorities in Physics Careers April 24, 2013 - 4:37pm Addthis Joining Director Dot Harris (second from left) were Marlene Kaplan, the Deputy Director of Education and director of EPP, National Oceanic and Atmospheric Administration, Claudia Rankins, a Program Officer with the National Science Foundation and Jim Stith, the past Vice-President of the American Institute of

  3. Fossil Energy Acting Assistant Secretary Recognized at Black Engineer of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    the Year Awards | Department of Energy Fossil Energy Acting Assistant Secretary Recognized at Black Engineer of the Year Awards Fossil Energy Acting Assistant Secretary Recognized at Black Engineer of the Year Awards February 19, 2013 - 8:54am Addthis Director Dot Harris presents Chris Smith, Principal Deputy Assistant Secretary and Acting Assistant Secretary of Fossil Energy, with a professional achievement award at the Black Engineer of the Year Awards conference this February. Photo

  4. Giving Back Through Our Talented STEM Professionals | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Giving Back Through Our Talented STEM Professionals Giving Back Through Our Talented STEM Professionals January 17, 2014 - 4:51pm Addthis Events like Argonne National Laboratory's annual Introduce a Girl to Engineering Day are produced with the volunteer support of the Department of Energy's STEM professionals. Above, Director Dot Harris visits the event in 2013. Events like Argonne National Laboratory's annual Introduce a Girl to Engineering Day are produced with the volunteer support of the

  5. Conversations and Connections - The Expertise of our Small Business

    Office of Environmental Management (EM)

    Program Managers | Department of Energy Conversations and Connections - The Expertise of our Small Business Program Managers Conversations and Connections - The Expertise of our Small Business Program Managers August 20, 2012 - 2:57pm Addthis Freda Hopper serves as a Small Business Program Manager at Oak Ridge Operations Office, helping small businesses learn how to work with the Department and access contract opportunities. Here, she joins Dot Harris (at podium) at a Small Business Summit

  6. Who's Involved | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    2014 DOE CFC Campaign Leadership Chair Ernest Moniz, Secretary of Energy Vice Chair Dot Harris, Director, Office of Economic Impact and Diversity Champion David M. Klaus, Deputy Under Secretary for Management and Performance Loaned Executive Kendra Riley, CFC National Capital Area Campaign Manager Neil Schuldenfrei, Office of Economic Impact and Diversity Deputy Campaign Manager Amanda Quinones, Office of Economic Impact and Diversity Project Manager Andre Sayles, Office of Economic Impact and

  7. Ambassadors of the Minorities in Energy Initiative | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Initiative » Ambassadors of the Minorities in Energy Initiative Ambassadors of the Minorities in Energy Initiative Secretary Ernest Moniz, Marillyn A. Hewson (Lockheed Martin Corporation's Chairman, President and CEO), and Director Dot Harris gather with a few of the 2015 newly appointed Minorities in Energy Ambassadors and Champions during the Minorities in Energy Year II Anniversary Forum on October 6, 2015. Secretary Ernest Moniz, Marillyn A. Hewson (Lockheed Martin Corporation's Chairman,

  8. Contact Us | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Contact Us Contact Us Office of Economic Impact & Diversity 1000 Independence Ave., SW Washington, DC 20585 Phone: (202) 586-8383 Fax: (202) 586-3075 Office of the Director Director, The Honorable LaDoris 'Dot' Harris Principal Deputy Director, Andre H. Sayles, Ph.D. Office of Minority Education and Community Development Deputy Director, Annie Whatle Annie.Whatley@hq.doe.gov Office of Minority Business and Economic Development Deputy Director, Karen Atkinson Karen.Atkinson@hq.doe.gov Office

  9. Modeling of the quantum dot filling and the dark current of quantum dot infrared photodetectors

    SciTech Connect (OSTI)

    Ameen, Tarek A.; El-Batawy, Yasser M.; Abouelsaood, A. A.

    2014-02-14

    A generalized drift-diffusion model for the calculation of both the quantum dot filling profile and the dark current of quantum dot infrared photodetectors is proposed. The confined electrons inside the quantum dots produce a space-charge potential barrier between the two contacts, which controls the quantum dot filling and limits the dark current in the device. The results of the model reasonably agree with a published experimental work. It is found that increasing either the doping level or the temperature results in an exponential increase of the dark current. The quantum dot filling turns out to be nonuniform, with a dot near the contacts containing more electrons than one in the middle of the device where the dot occupation approximately equals the number of doping atoms per dot, which means that quantum dots away from contacts will be nearly unoccupied if the active region is undoped.

  10. Quantum Dot Light Emitting Diode

    SciTech Connect (OSTI)

    Keith Kahen

    2008-07-31

    The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m2, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.

  11. Quantum Dot Light Emitting Diode

    SciTech Connect (OSTI)

    Kahen, Keith

    2008-07-31

    The project objective is to create low cost coatable inorganic light emitting diodes, composed of quantum dot emitters and inorganic nanoparticles, which have the potential for efficiencies equivalent to that of LEDs and OLEDs and lifetime, brightness, and environmental stability between that of LEDs and OLEDs. At the end of the project the Recipient shall gain an understanding of the device physics and properties of Quantum-Dot LEDs (QD-LEDs), have reliable and accurate nanocrystal synthesis routines, and have formed green-yellow emitting QD-LEDs with a device efficiency greater than 3 lumens/W, a brightness greater than 400 cd/m{sup 2}, and a device operational lifetime of more than 1000 hours. Thus the aim of the project is to break the current cost-efficiency paradigm by creating novel low cost inorganic LEDs composed of inorganic nanoparticles.

  12. Promising future of quantum dots explored in conference

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Promising future of quantum dots explored Promising future of quantum dots explored in conference Researchers are gathering to reflect on two decades of quantum dot research at a special topical conference, "20 Years of Quantum Dots at Los Alamos" April 13, 2015 Quantum dot LSC devices under ultraviolet illumination. Quantum dot LSC devices under ultraviolet illumination. Contact Los Alamos National Laboratory Nancy Ambrosiano Communications Office (505) 667-0471 Email "This

  13. Generation of even harmonics in coupled quantum dots (Journal...

    Office of Scientific and Technical Information (OSTI)

    Generation of even harmonics in coupled quantum dots Citation Details In-Document Search Title: Generation of even harmonics in coupled quantum dots Using the spatial-temporal...

  14. Next-Generation "Giant" Quantum Dots: Performance-Engineered...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    "Giant" Quantum Dots: Performance-Engineered for Lighting Next-Generation "Giant" Quantum Dots: Performance-Engineered for Lighting Lead Performer: Los Alamos National Laboratory - ...

  15. Single-dot optical emission from ultralow density well-isolated InP quantum dots

    SciTech Connect (OSTI)

    Ugur, A.; Hatami, F.; Masselink, W. T.; Vamivakas, A. N.; Lombez, L.; Atatuere, M.

    2008-10-06

    We demonstrate a straightforward way to obtain single well-isolated quantum dots emitting in the visible part of the spectrum and characterize the optical emission from single quantum dots using this method. Self-assembled InP quantum dots are grown using gas-source molecular-beam epitaxy over a wide range of InP deposition rates, using an ultralow growth rate of about 0.01 atomic monolayers/s, a quantum-dot density of 1 dot/{mu}m{sup 2} is realized. The resulting isolated InP quantum dots embedded in an InGaP matrix are individually characterized without the need for lithographical patterning and masks on the substrate. Such low-density quantum dots show excitonic emission at around 670 nm with a linewidth limited by instrument resolution. This system is applicable as a single-photon source for applications such as quantum cryptography.

  16. Thick-shell nanocrystal quantum dots

    DOE Patents [OSTI]

    Hollingsworth, Jennifer A. (Los Alamos, NM); Chen, Yongfen (Eugene, OR); Klimov, Victor I. (Los Alamos, NM); Htoon, Han (Los Alamos, NM); Vela, Javier (Los Alamos, NM)

    2011-05-03

    Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes.

  17. Theory Of Alkyl Terminated Silicon Quantum Dots

    SciTech Connect (OSTI)

    Reboredo, F; Galli, G

    2004-08-19

    We have carried out a series of ab-initio calculations to investigate changes in the optical properties of Si quantum dots as a function of surface passivation. In particular, we have compared hydrogen passivated dots with those having alkyl groups at the surface. We find that, while on clusters with reconstructed surfaces a complete alkyl passivation is possible, steric repulsion prevents full passivation of Si dots with unreconstructed surfaces. In addition, our calculations show that steric repulsion may have a dominant effect in determining the surface structure, and eventually the stability of alkyl passivated clusters, with results dependent on the length of the carbon chain. Alkyl passivation weakly affects optical gaps of silicon quantum dots, while it substantially decreases ionization potentials and electron affinities and affect their excited state properties. On the basis of our results we propose that alkyl terminated quantum dots may be size selected taking advantage of the change in ionization potential as a function of the cluster size.

  18. Leveling the Playing Field for Women: Work at the Energy Department |

    Office of Environmental Management (EM)

    Department of Energy Leveling the Playing Field for Women: Work at the Energy Department Leveling the Playing Field for Women: Work at the Energy Department August 15, 2012 - 1:40pm Addthis Karl Fraiser, a member of the Savannah River Special Emphasis Planning Committee, meets with Dot Harris at the site’s Women’s Equality Day Celebration. | Photo by Rob Davis, Savannah River Site. Karl Fraiser, a member of the Savannah River Special Emphasis Planning Committee, meets with Dot

  19. First principle thousand atom quantum dot calculations

    SciTech Connect (OSTI)

    Wang, Lin-Wang; Li, Jingbo

    2004-03-30

    A charge patching method and an idealized surface passivation are used to calculate the single electronic states of IV-IV, III-V, II-VI semiconductor quantum dots up to a thousand atoms. This approach scales linearly and has a 1000 fold speed-up compared to direct first principle methods with a cost of eigen energy error of about 20 meV. The calculated quantum dot band gaps are parametrized for future references.

  20. Structure in solution of the RNAter dot DNA hybrid (rA) sub 8 ter dot (dT)

    Office of Scientific and Technical Information (OSTI)

    sub 8 determined by NMR and Raman spectroscopy (Journal Article) | SciTech Connect Structure in solution of the RNAter dot DNA hybrid (rA) sub 8 ter dot (dT) sub 8 determined by NMR and Raman spectroscopy Citation Details In-Document Search Title: Structure in solution of the RNAter dot DNA hybrid (rA) sub 8 ter dot (dT) sub 8 determined by NMR and Raman spectroscopy The solution structure of the hybrid RNA{center dot}DNA octamer (rA){sub 8}{center dot}(dT){sub 8} has been determined by

  1. Surface treatment of nanocrystal quantum dots after film deposition

    DOE Patents [OSTI]

    Sykora, Milan; Koposov, Alexey; Fuke, Nobuhiro

    2015-02-03

    Provided are methods of surface treatment of nanocrystal quantum dots after film deposition so as to exchange the native ligands of the quantum dots for exchange ligands that result in improvement in charge extraction from the nanocrystals.

  2. Senate Confirms DOE Nominees Daniel Poneman, David Sandalow, Kristina

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Johnson, Steve Koonin, Scott Harris, and Ines Triay | Department of Energy Confirms DOE Nominees Daniel Poneman, David Sandalow, Kristina Johnson, Steve Koonin, Scott Harris, and Ines Triay Senate Confirms DOE Nominees Daniel Poneman, David Sandalow, Kristina Johnson, Steve Koonin, Scott Harris, and Ines Triay May 21, 2009 - 12:00am Addthis WASHINGTON, D.C. -- This week, the Senate confirmed six DOE nominees, including Deputy Secretary Daniel Poneman, Under Secretary for Energy Kristina

  3. Alumni | Photosynthetic Antenna Research Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Alumni Alumni PARC/I-CARES CERTIFICATE IN RENEWABLE ENERGY AND THE ENVIRONMENT ALUMNI Harry Bolson/Bachelor's degree in Finance & Entrepreneurship (Class of 2014) As part of the requirements for the certificate program, Harry developed a learning module entitled "Activities for Engaging High School Students in Energy Studies, which is available on the PARC website. He also helped to found and served as President of Washington University's chapter of Net IMpact. Harry is now employed as

  4. Microsoft PowerPoint - Pete H's 2008 SWPA Conf Pres(NWK Proj's Impact Fed Power).ppt

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    PROJECTS IMPACTING FEDERAL POWER KANSAS CITY DISTRICT * AmerenUE's (Bagnell Dam) FERC Re-licensing Impacts, Harry S. Truman Project * Draft Tube Bulkheads and Cylinder Hoists Repair Project, Harry S. Truman Power Plant * Water Supply Storage Reallocation, Stockton Project AmerenUE (Bagnell Dam) FERC Re-licensing Impacts at Harry S. Truman Project * Article 409 of the new FERC license recommended that AmerenUE enter into consultation with the Corps concerning ramp down rates at Truman to help

  5. MEMORADUM OF EX PARTE COMMUNICATION WITH THE DEPARTMENT OF ENERGY

    Office of Environmental Management (EM)

    HARRIS, WILTSHIRE & GRANNIS LLP | 1919 M STREET | EIGHTH FLOOR | WASHINGTON DC 20036 | T 202 730 1300 | F 202 730 1301 MEMORADUM OF EX PARTE COMMUNICATION WITH THE DEPARTMENT OF ENERGY Meeting Date: March 31, 2015 Attendees Ellen C. Ginsberg, Vice President and General Counsel, Nuclear Energy Institute (NEI); Scott Blake Harris, Chairman, Harris, Wiltshire & Grannis LLP; Steven Croley, General Counsel, Department of Energy (DOE); James (Ben) McRae, Assistant General Counsel, Department

  6. MEMORANDUM OF EX PARTE COMMUNICATION WITH THE DEPARTMENT OF ENERGY

    Office of Environmental Management (EM)

    EX PARTE COMMUNICATION WITH THE DEPARTMENT OF ENERGY Date of Meeting: December 30, 2014 Attendees: Scott Blake Harris, Harris, Wiltshire & Grannis LLP; Ellen Ginsberg, General Counsel, Nuclear Energy Institute; and Steven Croley, General Counsel of the Department of Energy Summary of what was discussed: Mr. Harris and Ms. Ginsberg discussed Part 810 of the Department's rules, and the September 2011 Notice of Proposed Rulemaking (NOPR) and the July 2013 Supplemental Notice of Proposed

  7. Synthesis of Non-blinking Semiconductor Quantum Dots Emitting...

    Office of Scientific and Technical Information (OSTI)

    37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 77 NANOSCIENCE AND NANOTECHNOLOGY; ALIGNMENT; CADMIUM; EMISSION SPECTRA; FLUORESCENCE; QUANTUM DOTS; RECOMBINATION;...

  8. RKKY interaction in a chirally coupled double quantum dot system...

    Office of Scientific and Technical Information (OSTI)

    Subject: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHIRALITY; EXCHANGE INTERACTIONS; KONDO EFFECT; MAGNETIC FIELDS; QUANTUM DOTS; TEMPERATURE DEPENDENCE ...

  9. Exciton binding energy in semiconductor quantum dots

    SciTech Connect (OSTI)

    Pokutnii, S. I.

    2010-04-15

    In the adiabatic approximation in the context of the modified effective mass approach, in which the reduced exciton effective mass {mu} = {mu}(a) is a function of the radius a of the semiconductor quantum dot, an expression for the exciton binding energy E{sub ex}(a) in the quantum dot is derived. It is found that, in the CdSe and CdS quantum dots with the radii a comparable to the Bohr exciton radii a{sub ex}, the exciton binding energy E{sub ex}(a) is substantially (respectively, 7.4 and 4.5 times) higher than the exciton binding energy in the CdSe and CdS single crystals.

  10. Quantum Dot-Based Cell Motility Assay

    SciTech Connect (OSTI)

    Gu, Weiwei; Pellegrino, Teresa; Parak Wolfgang J; Boudreau,Rosanne; Le Gros, Mark A.; Gerion, Daniele; Alivisatos, A. Paul; Larabell, Carolyn A.

    2005-06-06

    Because of their favorable physical and photochemical properties, colloidal CdSe/ZnS-semiconductor nanocrystals (commonly known as quantum dots) have enormous potential for use in biological imaging. In this report, we present an assay that uses quantum dots as markers to quantify cell motility. Cells that are seeded onto a homogeneous layer of quantum dots engulf and absorb the nanocrystals and, as a consequence, leave behind a fluorescence-free trail. By subsequently determining the ratio of cell area to fluorescence-free track area, we show that it is possible to differentiate between invasive and noninvasive cancer cells. Because this assay uses simple fluorescence detection, requires no significant data processing, and can be used in live-cell studies, it has the potential to be a powerful new tool for discriminating between invasive and noninvasive cancer cell lines or for studying cell signaling events involved in migration.

  11. Bilayer graphene quantum dot defined by topgates

    SciTech Connect (OSTI)

    Mller, Andr; Kaestner, Bernd; Hohls, Frank; Weimann, Thomas; Pierz, Klaus; Schumacher, Hans W., E-mail: hans.w.schumacher@ptb.de [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)

    2014-06-21

    We investigate the application of nanoscale topgates on exfoliated bilayer graphene to define quantum dot devices. At temperatures below 500 mK, the conductance underneath the grounded gates is suppressed, which we attribute to nearest neighbour hopping and strain-induced piezoelectric fields. The gate-layout can thus be used to define resistive regions by tuning into the corresponding temperature range. We use this method to define a quantum dot structure in bilayer graphene showing Coulomb blockade oscillations consistent with the gate layout.

  12. EA-1740: Final Environmental Assessment | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    chillers, and cooling tower at a district power plant that supplies the energy, heating, and cooling needs of the Texas Medical Center campus in Houston, Harris County, Texas. ...

  13. Paleogeographic Setting

    Office of Scientific and Technical Information (OSTI)

    April 1, 2005 Reporting Period End Date: September 30, 2005 Principal Authors: Douglas G. Patchen, Taury Smith, Ron Riley, Mark Baranoski, David Harris, John Hickman, John Bocan...

  14. Security Administration Production Office,

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and Services: Victoria Steward 43 years Facilities, Infrastructure and Services: Erby L. Harris and David Vann Production: Charles H. Neal Quality Assurance: Gary W. Eckert 41...

  15. Summer 2007 Cyclotron Institute REU Program

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of Upsilon Particles Using the Preshower Detector in STAR (presentation, poster) Chelsea Harris Texas Southern University Dr. Rand Watson A Pyro-Electric Crystal Particle...

  16. cover.indd

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... beam, detecting x-ray fluorescence signals from the components, and determining from ... for Improved Coordinate Measurement Machine Calibration Harry J. Clifford (QA-SCL) ...

  17. Lead Slowing Down Spectrometer Research Plans (Technical Report...

    Office of Scientific and Technical Information (OSTI)

    ; Kulisek, Jonathan A. ; Gavron, Victor ; Danon, Yaron ; Weltz, Adam ; Harris, Jason ; Stewart, T. Publication Date: 2013-03-22 OSTI Identifier: 1074313 Report Number(s):...

  18. Lead Slowing Down Spectrometer FY2013 Annual Report (Technical...

    Office of Scientific and Technical Information (OSTI)

    Jonathan A. ; Gavron, Victor A. ; Danon, Yaron ; Weltz, Adam ; Harris, Jason ; Stewart, T. Publication Date: 2013-10-29 OSTI Identifier: 1108159 Report Number(s):...

  19. Progress and issues in single well seismic imaging | Open Energy...

    Open Energy Info (EERE)

    Paper: Progress and issues in single well seismic imaging Authors Thomas M. Daley, Ernest L. Majer, Roland Gritto and Jerry M. Harris Conference 70th Annual International Meeting...

  20. Thermal Conductivity Measurements of Silicon Thin Films with...

    Office of Scientific and Technical Information (OSTI)

    Nanoscale Perforations. Abstract not provided. Authors: Harris, Charles Thomas ; Kim, Bongsang ; Reinke, Charles M. ; Hopkins, Patrick Edward ; Olsson, Roy H., ; El-Kady,...

  1. Rapid Field Measurement of Dissolved Inorganic Carbon Based on...

    Office of Scientific and Technical Information (OSTI)

    Authors: VESPER, DJ, Edenborn, Harry Publication Date: 2012-01-01 OSTI Identifier: 1061497 Report Number(s): NETL-461 Resource Type: Conference Research Org: National Energy ...

  2. Tax Credits, Rebates & Savings | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    electric cooperative that provides electric service to customers in Troup, Harris, Heard, Meriwether, Muscogee and Coweta counties in Georgia. Diverse Power offers......

  3. Chisago County, Minnesota: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    A. Places in Chisago County, Minnesota Center City, Minnesota Chisago City, Minnesota Harris, Minnesota Lindstrom, Minnesota North Branch, Minnesota Rush City, Minnesota Shafer,...

  4. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Response in Argillaceous Sedimentary Rock Repository for Direct Disposal of Dual-Purpose Canisters Zheng, Liange ; Rutqvist, Jonny ; Greenberg, Harris ; Birkholzer,...

  5. Climate Change 2001: The Scientific Basis

    Office of Scientific and Technical Information (OSTI)

    R. Dickerson, D. Etheridge, J. Feichter, P. Fraser, R. Friedl, J. Fuglestvedt, M. Gauss, L. Grenfell, A. Grbler, N. Harris, D. Hauglustaine, L. Horowitz, C. Jackman, D....

  6. The present invention relates to automated methods of introducing...

    Office of Scientific and Technical Information (OSTI)

    Harris H. 2 ; Isaacs, Farren J. 1 + Show Author Affiliations (Brookline, MA) (Cambridge, MA) Publication Date: 2012-04-10 OSTI Identifier: 1041008 Report Number(s):...

  7. Multiplex automated genome engineering Church, George M; Wang...

    Office of Scientific and Technical Information (OSTI)

    Multiplex automated genome engineering Church, George M; Wang, Harris H; Isaacs, Farren J The present invention relates to automated methods of introducing multiple nucleic acid...

  8. Weerts to lead Physical Sciences and Engineering directorate...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Weerts to lead Physical Sciences and Engineering directorate By Lynn Tefft Hoff * August 10, 2015 Tweet EmailPrint Hendrik (Harry) Joseph Weerts has been named the associate...

  9. Towns County, Georgia: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Number 4 Climate Zone Subtype A. Places in Towns County, Georgia Hiawassee, Georgia Young Harris, Georgia Retrieved from "http:en.openei.orgwindex.php?titleTownsCounty,G...

  10. An in-situ TEM liquid cell for imaging electrode/electrolyte...

    Office of Scientific and Technical Information (OSTI)

    Patrick ; Jungjohann, Katherine Leigh 1 ; Zavadil, Kevin Robert 1 ; Leenheer, Andrew Jay 1 ; Harris, Charles Thomas 1 + Show Author Affiliations Sandia National...

  11. Karen Wayland | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    During that time she chaired the national environmental community's climate and energy coalition. Dr. Wayland has also worked in the office of Senator Harry Reid, where she covered ...

  12. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... Temperature in the Laboratory Schubnel, Alexandre ; Brunet, Fabrice ; Hilairet, Nadege ; Gasc, Julien ; Wang, Yanbin ; Green, II, Harry W. ; CNRS-UMR) ; UCR) ; UC) December 2013

  13. Department of Energy Finalizes Loan Guarantee for New Transmission...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    and capable of delivering low-cost renewable energy to market," said Nevada Senator Harry Reid. "This transmission line is a major step toward unlocking Nevada's vast clean ...

  14. The Process, Methods and Tool Used To Integrate Safety During...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Independent Oversight Review, Y-12 National Security Complex - March 2014 Microsoft PowerPoint - 13 DOE PM Workshop UPF Presentation revised - Harry Peters Compatibility Mode

  15. A Minority Serving Institution Leads the Way in Better Buildings...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Coons, U.S. Representative John Carney, and Delaware State University President Harry Williams at Delaware State University, a Historically Black College and University (HBCU)....

  16. Property:Knows | Open Energy Information

    Open Energy Info (EERE)

    Jorn.Aabakken +, ... GregZiebold + Woodjr +, Twong +, Rgelman +, ... H Harris + DWC Bot + J JZ + GregZiebold +, Woodjr +, Dbrodt +, ... Jackie Lyndon + Meredith1219 +, Graham7781 +...

  17. Combining Quantitative Electrochemistry and Electron Microscopy...

    Office of Scientific and Technical Information (OSTI)

    Silicon Nanowires. Authors: Zavadil, Kevin R. ; Liu, Yang ; Harris, Charles Thomas ; Sullivan, John P. 1 + Show Author Affiliations (Sandia National Laboratories, Livermore, CA)...

  18. DOE Hosts Public Roundtable Discussion of Smart-Grid Data Access...

    Broader source: Energy.gov (indexed) [DOE]

    Inquiry that DOE published in the Federal Register on May 11, 2010. DOE General Counsel Scott Blake Harris said, "Effective data management and privacy protection will be...

  19. Sandia Energy - SunShot Grand Challenge Summit and Technology...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and academia to strengthen U.S. leadership in global clean energy. Secretary Chu, Harry Atwater (Director, EFRC on Light-Matter Interactions in Solar Energy Conversion),...

  20. The Columbia River System Inside Story

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    (Agency Valley) Juntura (Warmsprings) Mahon s Reservoir Harper Bully Creek Deadwood Harry Nelson Mann Creek Mason Dam (Phillips Lake) Thief Valley Non-Federal with Power Owyhee...

  1. Sandia Energy - New Liquid Salt Electrolytes Could Lead to Cost...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Salt Electrolytes Could Lead to Cost-Effective Flow Batteries Chemical technologist Harry Pratt synthesizes a copper-based ionic liquid. (Photo by Randy Montoya) Sandia...

  2. The New Face of Protein-bound Copper: The Type Zero Copper Site

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    variant of Pseudomonas aeruginosa azurin 2, Kyle M. Lancaster, under the guidance of Harry B. Gray and John H. Richards at the California Institute of Technology, discovered a...

  3. Sandia National Laboratories: Careers: Students & Postdocs: Fellowship...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Truman Fellowship Sandia established the President Harry S. Truman Fellowship in National Security Science and Engineering to attract the best nationally recognized new Ph.D....

  4. The Columbia River System: Inside Story

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    (Agency Valley) Juntura (Warmsprings) Mahon's Reservoir Harper Bully Creek Deadwood Harry Nelson Mann Creek Mason Dam (Phillips Lake) Thief Valley Non-Federal with Power Owyhee...

  5. Deep Drilling to the Magmatic Environment in Long Valley Caldera...

    Open Energy Info (EERE)

    and eventually into this magma body. Authors John B. Rundle, Charles R. Carrigan, Harry C. Hardee and William C. Luth Published Journal EOS, Transactions American Geophysical...

  6. SANDIA REPORT SAND2014-3416 Unlimited Release

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    SAND2014-3416 Unlimited Release Printed April 2014 Safety, Codes and Standards for Hydrogen Installations: Hydrogen Fueling System Footprint Metric Development A.P. Harris,...

  7. Department of Energy to Host Spectrum Policy Seminar for the...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    ensure priority restoration and priority calling for utilities during times of emergency. Scott Blake Harris, General Counsel, will make introductory remarks. Featured speakers...

  8. Plains and Eastern Clean Line

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    ... Michael Baker Jr., Inc., 2002-2006 - Project Manager URS CorporationDames & Moore Group, 1998-2002 - Senior Environmental Planner Harris County, Texas Pollution Control ...

  9. Department of Energy Response to Correspondence from Mary Celeste...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    from Mary Celeste Harris related to District of Columbia Public Service Commission Docket No. EO-05-01 regarding operation of Mirnat Corporation's Potomac River Generating Station. ...

  10. Task force appendix cover.indd

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Doug Mercer, CRESP Max Power, Ecology Chuck Powers, CRESP Jamie Zeisloft, DOE-RL John Price, Ecology Steve Smith, CRESP Joy Turner, Ecology Stuart Harris, CTUIR Craig...

  11. Hydrogen Compression, Storage, and Dispensing Cost Reduction...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Aaron Harris, Sandia National Laboratories CSD Safety and Reliability Data, Kevin Harrison, National Renewable Energy Laboratory Coriolis Meters for Hydrogen Dispensing ...

  12. ALSNews Vol. 334

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    past 30 years as a research scientist, testing and investigating various promising materials and technologies. As a result, Harris knows a thing or two about what the industry...

  13. Light-Material Interactions in Energy Conversion - Energy Frontier...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Harvesting RG Leader: Shanhui Fan Affiliated PIs: Harry Atwater, Paul Braun, Jennifer Lewis, Austin Minnich, John Rogers, and Eli Yablonovitch Refractive index design via porous...

  14. Light-Material Interactions in Energy Conversion - Energy Frontier...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    4: Programmable Assembly of Photonic and Electronic Architectures RG Leader: Jennifer Lewis Affiliated PIs: Harry Atwater, Paul Braun, Nate Lewis, Ralph Nuzzo, John Rogers, Eli...

  15. AARD Membership Update | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    Nan Phinney, (Stanford Linear Accelerator Center ) Jamie Rosenzweig, ( University of California at Los Angeles ) A. J. Stewart Smith, ( Princeton University ) Harry Weerts, ( ...

  16. Non-equilibrium electronic and phononic specific heat in systems...

    Office of Scientific and Technical Information (OSTI)

    Abstract not provided. Authors: Duda, John Charles ; English, Timothy Stephen ; Harris, Charles Thomas ; Piekos, Edward S. 1 ; Jones, Reese E. ; Hopkins, Patrick E. + Show Author ...

  17. Clifton Truman Daniel's visit to Oak Ridge and Y-12, part 2

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2 President Harry S. Truman's grandson, Clifton Truman Daniel, after visiting Japan to attend an anniversary of the bombing of Hiroshima and Nagasaki, recently visited Oak Ridge to...

  18. Update on Establishing the Feasibility of Lead Slowing Down Spectrosco...

    Office of Scientific and Technical Information (OSTI)

    Authors: Kulisek, Jonathan A. ; Anderson, Kevin K. ; Casella, Andrew M. ; Warren, Glen A. ; Gavron, Victor A. ; Danon, Yaron ; Weltz, Adam ; Harris, Jason ; Imel, G. R. ; Stewart, ...

  19. Lead Slowing Down Spectrometry Analysis of Data from Measurements...

    Office of Scientific and Technical Information (OSTI)

    Authors: Warren, Glen A. ; Anderson, Kevin K. ; Kulisek, Jonathan A. ; Danon, Yaron ; Weltz, Adam ; Gavron, Victor A. ; Harris, Jason ; Stewart, Trevor N. Publication Date: ...

  20. Lead Slowing Down Spectrometer FY2013 Annual Report (Technical...

    Office of Scientific and Technical Information (OSTI)

    Authors: Warren, Glen A. ; Kulisek, Jonathan A. ; Gavron, Victor A. ; Danon, Yaron ; Weltz, Adam ; Harris, Jason ; Stewart, T. Publication Date: 2013-10-29 OSTI Identifier: 1108159 ...

  1. Lead Slowing Down Spectrometer Research Plans (Technical Report...

    Office of Scientific and Technical Information (OSTI)

    Authors: Warren, Glen A. ; Kulisek, Jonathan A. ; Gavron, Victor ; Danon, Yaron ; Weltz, Adam ; Harris, Jason ; Stewart, T. Publication Date: 2013-03-22 OSTI Identifier: 1074313 ...

  2. STATISTICAL PERFORMANCE EVALUATION OF SPRING OPERATED PRESSURE...

    Office of Scientific and Technical Information (OSTI)

    Title: STATISTICAL PERFORMANCE EVALUATION OF SPRING OPERATED PRESSURE RELIEF VALVE RELIABILITY IMPROVEMENTS 2004 TO 2014 Authors: Harris, S. ; Gross, R. ; Watson, H. Publication ...

  3. "Title","Creator/Author","Publication Date","OSTI Identifier...

    Office of Scientific and Technical Information (OSTI)

    The Science of Battery Degradation.","Sullivan, John P; Fenton, Kyle R Sandia National Laboratories, Albuquerque, NM; El Gabaly Marquez, Farid; Harris, Charles Thomas Sandia...

  4. Kondo and mixed-valence regimes in multilevel quantum dots

    SciTech Connect (OSTI)

    Chudnovskiy, A. L.; Ulloa, S. E.

    2001-04-15

    We investigate the dependence of the ground state of a multilevel quantum dot on the coupling to an external fermionic system and on the interactions in the dot. As the coupling to the external system increases, the rearrangement of the effective energy levels in the dot signals the transition from the Kondo regime to a mixed-valence (MV) regime. The MV regime in a two-level dot is characterized by an intrinsic mixing of the levels in the dot, resulting in nonperturbative subtunneling and supertunneling phenomena that strongly influence the Kondo effect.

  5. Synthesis of CdSe quantum dots for quantum dot sensitized solar cell

    SciTech Connect (OSTI)

    Singh, Neetu Kapoor, Avinashi; Kumar, Vinod; Mehra, R. M.

    2014-04-24

    CdSe Quantum Dots (QDs) of size 0.85 nm were synthesized using chemical route. ZnO based Quantum Dot Sensitized Solar Cell (QDSSC) was fabricated using CdSe QDs as sensitizer. The Pre-synthesized QDs were found to be successfully adsorbed on front ZnO electrode and had potential to replace organic dyes in Dye Sensitized Solar Cells (DSSCs). The efficiency of QDSSC was obtained to be 2.06 % at AM 1.5.

  6. Empowering the Next Generation: Connecting the U.S. and African Nations

    Energy Savers [EERE]

    through Technical Exchanges | Department of Energy Empowering the Next Generation: Connecting the U.S. and African Nations through Technical Exchanges Empowering the Next Generation: Connecting the U.S. and African Nations through Technical Exchanges July 31, 2014 - 2:55pm Addthis Director Dot Harris meets with Subramania I. Sritharan PhD, P.E., Central State University, and John J. Qu, Ph.D., George Mason University, fellow participants at the May 2014 U.S.-Africa Energy Ministerial in

  7. No Small Task: How Small Businesses are Critical to our Energy Future |

    Office of Environmental Management (EM)

    Department of Energy No Small Task: How Small Businesses are Critical to our Energy Future No Small Task: How Small Businesses are Critical to our Energy Future July 3, 2012 - 1:25pm Addthis Shelton Clark, President of Eberline Services, receives the Small Business of the Year award from Dot Harris, Director of the Office of Economic Impact and Diversity. Eberline Services, a New Mexico-based small business, gets 90% of their business from the Energy Department. They specialize in

  8. EM Wins Award for Role as Strong Small Businesses Advocate | Department of

    Office of Environmental Management (EM)

    Energy Award for Role as Strong Small Businesses Advocate EM Wins Award for Role as Strong Small Businesses Advocate June 28, 2012 - 12:00pm Addthis DOE Office of Economic Impact and Diversity Director Dot Harris, left, presents the Sub-to-Prime Small Business Champion of the Year Award to EM Small Business Advocate Kay Rash, center, and EM Deputy Assistant Secretary for Acquisition and Project Management Jack Surash during DOE’s Fiscal Year 2011 DOE Secretarial Small Business Awards

  9. Geometric spin manipulation in semiconductor quantum dots

    SciTech Connect (OSTI)

    Prabhakar, Sanjay Melnik, Roderick; Inomata, Akira

    2014-04-07

    We propose a method to flip the spin completely by an adiabatic transport of quantum dots. We show that it is possible to flip the spin by inducing a geometric phase on the spin state of a quantum dot. We estimate the geometric spin flip time (approximately 2 ps) which turned out to be much shorter than the experimentally reported decoherence time (approximately 100 ns) that would provide an alternative means of fliping the spin before reaching decoherence. It is important that both the Rashba coupling and the Dresselhaus coupling are present for inducing a phase necessary for spin flip. If one of them is absent, the induced phase is trivial and irrelevant for spin-flip.

  10. Research Challenge 2: Quantum Dots and Phosphors

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2: Quantum Dots and Phosphors - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs

  11. Controlling quantum dot energies using submonolayer bandstructure engineering

    SciTech Connect (OSTI)

    Yu, L.; Law, S.; Wasserman, D.; Jung, D.; Lee, M. L.; Shen, J.; Cha, J. J.

    2014-08-25

    We demonstrate control of energy states in epitaxially-grown quantum dot structures formed by stacked submonolayer InAs depositions via engineering of the internal bandstructure of the dots. Transmission electron microscopy of the stacked sub-monolayer regions shows compositional inhomogeneity, indicative of the presence of quantum dots. The quantum dot ground state is manipulated not only by the number of deposited InAs layers, but also by control of the thickness and material composition of the spacing layers between submonolayer InAs depositions. In this manner, we demonstrate the ability to shift the quantum dot ground state energy at 77?K from 1.38?eV to 1.88?eV. The results presented offer a potential avenue towards enhanced control of dot energies for a variety of optoelectronic applications.

  12. Nanoscale engineering boosts performance of quantum dot light emitting

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    diodes Quantum dot light emitting diodes Nanoscale engineering boosts performance of quantum dot light emitting diodes Quantum dots are nano-sized semiconductor particles whose emission color can be tuned by simply changing their dimensions. October 25, 2013 Postdoctoral researcher Young-Shin Park characterizing emission spectra of LEDs in the Los Alamos National Laboratory optical laboratory. Postdoctoral researcher Young-Shin Park characterizing emission spectra of LEDs in the Los Alamos

  13. DOT Awards University Transportation Centers $63 Million | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Energy DOT Awards University Transportation Centers $63 Million DOT Awards University Transportation Centers $63 Million October 23, 2013 - 12:00am Addthis The U.S. Department of Transportation’s (DOT) on September 26 announced approximately $63 million in grants to 33 University Transportation Centers to advance research and education programs that address critical transportation challenges. The selected universities will research a wide range of transportation-related issues

  14. Sandia Energy - Research Challenge 2: Quantum Dots and Phosphors

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    2: Quantum Dots and Phosphors Home Energy Research EFRCs Solid-State Lighting Science EFRC Our SSLS EFRC's Scientific Research Challenges and Publications Research Challenge 2:...

  15. Mastermind Session: Connecting the Dots Between the Real Estate...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    the Dots Between the Real Estate Market and Residential Energy Efficiency Featuring Host Rich Dooley, Arlington County, VA, Call Slides and Discussion Summary, August 14, 2014. ...

  16. Tuning Into the Right Wavelength: Quantum Dot Rainbow Increases...

    Office of Science (SC) Website

    Sequentially deposited green, orange, and red-emitting quantum dots serve as sensitizers ... converted more light than expected into energy compared with solar cells containing only ...

  17. Cornell dots research collaboration leads to $10M cancer center...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    at MSKCC in New York City - will focus on melanoma (skin) and malignant brain cancers. ... Assessment of particles in brain tumors for cancer therapy. C dots successfully have ...

  18. Applicability of the {bold k}{center_dot}{bold p} method to the electronic structure of quantum dots

    SciTech Connect (OSTI)

    Fu, H.; Wang, L.; Zunger, A.

    1998-04-01

    The {bold k}{center_dot}{bold p} method has become the {open_quotes}standard model{close_quotes} for describing the electronic structure of nanometer-size quantum dots. In this paper we perform parallel {bold k}{center_dot}{bold p} (6{times}6 and 8{times}8) and direct-diagonalization pseudopotential studies on spherical quantum dots of an ionic material{emdash}CdSe, and a covalent material{emdash}InP. By using an equivalent input in both approaches, i.e., starting from a given atomic pseudopotential and deriving from it the Luttinger parameters in {bold k}{center_dot}{bold p} calculation, we investigate the effect of the different underlying wave-function representations used in {bold k}{center_dot}{bold p} and in the more exact pseudopotential direct diagonalization. We find that (i) the 6{times}6{bold k}{center_dot}{bold p} envelope function has a distinct (odd or even) parity, while atomistic wave function is parity-mixed. The 6{times}6{bold k}{center_dot}{bold p} approach produces an incorrect order of the highest valence states for both InP and CdSe dots: the p-like level is above the s-like level. (ii) It fails to reveal that the second conduction state in small InP dots is folded from the L point in the Brillouin zone. Instead, all states in {bold k}{center_dot}{bold p} are described as {Gamma}-like. (iii) The {bold k}{center_dot}{bold p} overestimates the confinement energies of both valence states and conduction states. A wave-function projection analysis shows that the principal reasons for these {bold k}{center_dot}{bold p} errors in dots are (a) use of restricted basis set, and (b) incorrect {ital bulk} dispersion relation. Error (a) can be reduced only by increasing the number of basis functions. Error (b) can be reduced by altering the {bold k}{center_dot}{bold p} implementation so as to bend upwards the second lowest bulk band, and to couple the conduction band into the s-like dot valence state. Our direct diagonalization approach provides an accurate and practical replacement to the standard model in that it is rather general, and can be performed simply on a standard workstation. {copyright} {ital 1998} {ital The American Physical Society}

  19. Hygrogenics Corporation | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Hygrogenics Corporation Hygrogenics Corporation Presented by Kevin Harris at the National Hydrogen Assocation Conference and Hydrogen Expo PDF icon harris_telecom_backup_power.pdf More Documents & Publications Fuel Cells for Backup Power in Telecommunications Facilities (Fact Sheet) 2008 Fuel Cell Technologies Market Report 2008 Fuel Cell Technologies Market Report

  20. Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous

    Office of Scientific and Technical Information (OSTI)

    optical imaging, photothermal effect and thermometry (Journal Article) | SciTech Connect Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous optical imaging, photothermal effect and thermometry Citation Details In-Document Search Title: Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous optical imaging, photothermal effect and thermometry Hybrid semiconductor-metal nanoscale constructs are of both fundamental and practical interest.

  1. DOT-7A packaging test procedure

    SciTech Connect (OSTI)

    Kelly, D.L.

    1995-01-23

    This test procedure documents the steps involved with performance testing of Department of Transportation Specification 7A (DOT-7A) Type A packages. It includes description of the performance tests, the personnel involved, appropriate safety considerations, and the procedures to be followed while performing the tests. Westinghouse Hanford Company (WHC) is conducting the evaluation and testing discussed herein for the Department of Energy-Headquarters, Division of Quality Verification and Transportation Safety (EH-321). Please note that this report is not in WHC format. This report is being submitted through the Engineering Documentation System so that it may be used for reference and information purposes.

  2. RKKY interaction in a chirally coupled double quantum dot system

    SciTech Connect (OSTI)

    Heine, A. W.; Tutuc, D.; Haug, R. J.; Zwicknagl, G.; Schuh, D.; Wegscheider, W.

    2013-12-04

    The competition between the Kondo effect and the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction is investigated in a double quantum dots system, coupled via a central open conducting region. A perpendicular magnetic field induces the formation of Landau Levels which in turn give rise to the so-called Kondo chessboard pattern in the transport through the quantum dots. The two quantum dots become therefore chirally coupled via the edge channels formed in the open conducting area. In regions where both quantum dots exhibit Kondo transport the presence of the RKKY exchange interaction is probed by an analysis of the temperature dependence. The thus obtained Kondo temperature of one dot shows an abrupt increase at the onset of Kondo transport in the other, independent of the magnetic field polarity, i.e. edge state chirality in the central region.

  3. Kondo effect in coupled quantum dots under magnetic fields

    SciTech Connect (OSTI)

    Aono, Tomosuke; Eto, Mikio

    2001-08-15

    The Kondo effect in coupled quantum dots is investigated theoretically under magnetic fields. We show that the magnetoconductance (MC) illustrates the peak structures of Kondo resonant spectra. When the dot-dot tunneling coupling V{sub C} is smaller than the dot-lead coupling {Delta} (level broadening), Kondo resonant levels appear at the Fermi level (E{sub F}). The Zeeman splitting of the levels weakens the Kondo effect, which results in a negative MC. When V{sub C} is larger than {Delta}, the Kondo resonances form bonding and antibonding levels, located below and above E{sub F}, respectively. We observe a positive MC since the Zeeman splitting increases the overlap between the levels at E{sub F}. In the presence of antiferromagnetic spin coupling between the dots, the sign of the MC can change as a function of the gate voltage.

  4. Competing interactions in semiconductor quantum dots

    SciTech Connect (OSTI)

    van den Berg, R.; Brandino, G. P.; El Araby, O.; Konik, R. M.; Gritsev, V.; Caux, J. -S.

    2014-10-01

    We introduce an integrability-based method enabling the study of semiconductor quantum dot models incorporating both the full hyperfine interaction as well as a mean-field treatment of dipole-dipole interactions in the nuclear spin bath. By performing free induction decay and spin echo simulations we characterize the combined effect of both types of interactions on the decoherence of the electron spin, for external fields ranging from low to high values. We show that for spin echo simulations the hyperfine interaction is the dominant source of decoherence at short times for low fields, and competes with the dipole-dipole interactions at longer times. On the contrary, at high fields the main source of decay is due to the dipole-dipole interactions. In the latter regime an asymmetry in the echo is observed. Furthermore, the non-decaying fraction previously observed for zero field free induction decay simulations in quantum dots with only hyperfine interactions, is destroyed for longer times by the mean-field treatment of the dipolar interactions.

  5. Competing interactions in semiconductor quantum dots

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    van den Berg, R.; Brandino, G. P.; El Araby, O.; Konik, R. M.; Gritsev, V.; Caux, J. -S.

    2014-10-14

    In this study, we introduce an integrability-based method enabling the study of semiconductor quantum dot models incorporating both the full hyperfine interaction as well as a mean-field treatment of dipole-dipole interactions in the nuclear spin bath. By performing free induction decay and spin echo simulations we characterize the combined effect of both types of interactions on the decoherence of the electron spin, for external fields ranging from low to high values. We show that for spin echo simulations the hyperfine interaction is the dominant source of decoherence at short times for low fields, and competes with the dipole-dipole interactions atmore » longer times. On the contrary, at high fields the main source of decay is due to the dipole-dipole interactions. In the latter regime an asymmetry in the echo is observed. Furthermore, the non-decaying fraction previously observed for zero field free induction decay simulations in quantum dots with only hyperfine interactions, is destroyed for longer times by the mean-field treatment of the dipolar interactions.« less

  6. Generation of even harmonics in coupled quantum dots

    SciTech Connect (OSTI)

    Guo Shifang; Duan Suqing; Yang Ning; Chu Weidong; Zhang Wei

    2011-07-15

    Using the spatial-temporal symmetry principle we developed recently, we propose an effective scheme for even-harmonics generation in coupled quantum dots. The relative intensity of odd and even harmonic components in the emission spectrum can be controlled by tuning the dipole couplings among the dots, which can be realized in experiments by careful design of the nanostructures. In particular, pure 2nth harmonics and (2n+1)th harmonics (where n is an integer) can be generated simultaneously with polarizations in two mutual perpendicular directions in our systems. An experimental design of the coupled dots system is presented.

  7. Zeno-logic applications of semiconductor quantum dots

    SciTech Connect (OSTI)

    Schneebeli, L.; Peyghambarian, N.; Feldtmann, T.; Kira, M.; Koch, S. W.

    2010-05-15

    Microscopic calculations show that CdSe-based semiconductor quantum dots with confined exciton and biexciton states are suitable candidates for Zeno-logic applications. The frequencies of the control and signal fields are chosen to guarantee very high transmission of the individual beams. If both fields are present simultaneously, they are strongly absorbed due to efficient ground-state-to-biexciton transitions. The optical Bloch equations for a three-level quantum-dot model with self-consistent light-matter coupling are solved numerically. The influence of dephasing and/or inhomogeneous dot distributions is analyzed and the conditions for satisfactory device operation are identified.

  8. Quantum Dot Tracers for Use in Engineered Geothermal | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Quantum Dot Tracers for Use in Engineered Geothermal Quantum Dot Tracers for Use in Engineered Geothermal Quantum Dot Tracers for Use in Engineered Geothermal presentation at the April 2013 peer review meeting held in Denver, Colorado. PDF icon quantum_dot_tracers_peer2013.pdf More Documents & Publications Tracer Methods for Characterizing Fracture Stimulation in Engineered Geothermal Systems (EGS) Quantum Dot Tracers for Use in Engineered Geothermal Systems Use of Tracers to Characterize

  9. Electron states in semiconductor quantum dots

    SciTech Connect (OSTI)

    Dhayal, Suman S.; Ramaniah, Lavanya M.; Ruda, Harry E.; Nair, Selvakumar V.

    2014-11-28

    In this work, the electronic structures of quantum dots (QDs) of nine direct band gap semiconductor materials belonging to the group II-VI and III-V families are investigated, within the empirical tight-binding framework, in the effective bond orbital model. This methodology is shown to accurately describe these systems, yielding, at the same time, qualitative insights into their electronic properties. Various features of the bulk band structure such as band-gaps, band curvature, and band widths around symmetry points affect the quantum confinement of electrons and holes. These effects are identified and quantified. A comparison with experimental data yields good agreement with the calculations. These theoretical results would help quantify the optical response of QDs of these materials and provide useful input for applications.

  10. Quantum Dot Tracers for Use in Engineered Geothermal Systems

    Broader source: Energy.gov [DOE]

    DOE Geothermal Peer Review 2010 - Presentation. Project objective: To develop and demonstrate a new class of tracers„semiconductor nanoparticles(quantum dots)„that offer great promise for use in characterizing fracture networks in EGS reservoirs.

  11. Quantum dot conjugates in a sub-micrometer fluidic channel

    DOE Patents [OSTI]

    Stavis, Samuel M. (Ithaca, NY); Edel, Joshua B. (Brookline, MA); Samiee, Kevan T. (Ithaca, NY); Craighead, Harold G. (Ithaca, NY)

    2008-07-29

    A nanofluidic channel fabricated in fused silica with an approximately 500 nm square cross section was used to isolate, detect and identify individual quantum dot conjugates. The channel enables the rapid detection of every fluorescent entity in solution. A laser of selected wavelength was used to excite multiple species of quantum dots and organic molecules, and the emission spectra were resolved without significant signal rejection. Quantum dots were then conjugated with organic molecules and detected to demonstrate efficient multicolor detection. PCH was used to analyze coincident detection and to characterize the degree of binding. The use of a small fluidic channel to detect quantum dots as fluorescent labels was shown to be an efficient technique for multiplexed single molecule studies. Detection of single molecule binding events has a variety of applications including high throughput immunoassays.

  12. Quantum dot conjugates in a sub-micrometer fluidic channel

    DOE Patents [OSTI]

    Stavis, Samuel M.; Edel, Joshua B.; Samiee, Kevan T.; Craighead, Harold G.

    2010-04-13

    A nanofluidic channel fabricated in fused silica with an approximately 500 nm square cross section was used to isolate, detect and identify individual quantum dot conjugates. The channel enables the rapid detection of every fluorescent entity in solution. A laser of selected wavelength was used to excite multiple species of quantum dots and organic molecules, and the emission spectra were resolved without significant signal rejection. Quantum dots were then conjugated with organic molecules and detected to demonstrate efficient multicolor detection. PCH was used to analyze coincident detection and to characterize the degree of binding. The use of a small fluidic channel to detect quantum dots as fluorescent labels was shown to be an efficient technique for multiplexed single molecule studies. Detection of single molecule binding events has a variety of applications including high throughput immunoassays.

  13. Synthesis of Non-blinking Semiconductor Quantum Dots Emitting...

    Office of Scientific and Technical Information (OSTI)

    Our previous work demonstrates that Quasi-Type II CdSeCdS core-shell quantum dots with ... synthesized to reduce cadmium exposure for applications in the biological environment. ...

  14. Comparison of quantum confinement effects between quantum wires and dots

    SciTech Connect (OSTI)

    Li, Jingbo; Wang, Lin-Wang

    2004-03-30

    Dimensionality is an important factor to govern the electronic structures of semiconductor nanocrystals. The quantum confinement energies in one-dimensional quantum wires and zero-dimensional quantum dots are quite different. Using large-scale first-principles calculations, we systematically study the electronic structures of semiconductor (including group IV, III-V, and II-VI) surface-passivated quantum wires and dots. The band-gap energies of quantum wires and dots have the same scaling with diameter for a given material. The ratio of band-gap-increases between quantum wires and dots is material-dependent, and slightly deviates from 0.586 predicted by effective-mass approximation. Highly linear polarization of photoluminescence in quantum wires is found. The degree of polarization decreases with the increasing temperature and size.

  15. Sandia Energy - Sandia Develops a Synthesis of Quantum Dots that...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Develops a Synthesis of Quantum Dots that Increases the Quantum Yield to 95.5% Home Energy Solid-State Lighting Office of Science News Energy Efficiency News & Events Research &...

  16. Plasmonic giant quantum dots: Hybrid nanostructures for truly...

    Office of Scientific and Technical Information (OSTI)

    We show here that photostable 'giant' quantum dots when placed at the center of an ultrathin gold shell retain their key optical property of bright and blinking-free ...

  17. TxDOT Access Management Manual | Open Energy Information

    Open Energy Info (EERE)

    Access Management Manual Jump to: navigation, search OpenEI Reference LibraryAdd to library Legal Document- OtherOther: TxDOT Access Management ManualLegal Abstract Manual prepared...

  18. Deformation potentials of CdSe quantum dots

    SciTech Connect (OSTI)

    Li, Jingbo; Wang, Lin-Wang

    2004-06-02

    The size dependent deformation potentials of CdSe quantum dots are studied by first principle and semi-empirical pseudopotentials calculations. They find that the amplitude of the quantum dot deformation potential is only slightly larger than the bulk value, and this increase is mostly caused by the off {Lambda} point deformation potentials in the bulk, which are larger in amplitude than the {Lambda} point deformation potential.

  19. Quantum Dot Materials Can Reduce Heat, Boost Electrical Output - News

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Releases | NREL Quantum Dot Materials Can Reduce Heat, Boost Electrical Output May 23, 2005 Golden, Colo. - Researchers at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) have shown that nanotechnology may greatly increase the amount of electricity produced by solar cells. In a paper published in a May issue of the American Chemical Society's Nano Letters journal, an NREL team found that tiny "nanocrystals," also known as "quantum dots,"

  20. Los Alamos Quantum Dots for Solar, Display Technology

    SciTech Connect (OSTI)

    Klimov, Victor

    2015-04-13

    Quantum dots are ultra-small bits of semiconductor matter that can be synthesized with nearly atomic precision via modern methods of colloidal chemistry. Their emission color can be tuned by simply varying their dimensions. Color tunability is combined with high emission efficiencies approaching 100 percent. These properties have recently become the basis of a new technology – quantum dot displays – employed, for example, in the newest generation of e-readers and video monitors.

  1. Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous

    Office of Scientific and Technical Information (OSTI)

    optical imaging, photothermal effect and thermometry (Journal Article) | SciTech Connect Journal Article: Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous optical imaging, photothermal effect and thermometry Citation Details In-Document Search Title: Plasmonic giant quantum dots: Hybrid nanostructures for truly simultaneous optical imaging, photothermal effect and thermometry × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This

  2. Controlling thermal conductance through quantum dot roughening at

    Office of Scientific and Technical Information (OSTI)

    interfaces. (Journal Article) | SciTech Connect Journal Article: Controlling thermal conductance through quantum dot roughening at interfaces. Citation Details In-Document Search Title: Controlling thermal conductance through quantum dot roughening at interfaces. Abstract not provided. Authors: Hopkins, Patrick Edward ; Duda, John C. ; Petz, Christopher W. ; Floro, Jerrold A. Publication Date: 2011-01-01 OSTI Identifier: 1110382 Report Number(s): SAND2011-0398J 473795 DOE Contract Number:

  3. NREL and Partners Demonstrate Quantum Dots that Assemble Themselves - News

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Releases | NREL and Partners Demonstrate Quantum Dots that Assemble Themselves Surprising breakthrough could bolster quantum photonics, solar cell efficiency February 8, 2013 Scientists from the U.S. Department of Energy's National Renewable Energy Laboratory and other labs have demonstrated a process whereby quantum dots can self-assemble at optimal locations in nanowires, a breakthrough that could improve solar cells, quantum computing, and lighting devices. A paper on the new technology,

  4. Los Alamos researchers unravel the mystery of quantum dot blinking

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Researchers unravel the mystery of quantum dot blinking Los Alamos researchers unravel the mystery of quantum dot blinking Most exciting is that the Los Alamos researchers have shown that blinking can be controlled and even completely suppressed electrochemically. November 9, 2011 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy

  5. Metal Halide Surface Treatment of Quantum Dots - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Advanced Materials Advanced Materials Find More Like This Return to Search Metal Halide Surface Treatment of Quantum Dots National Renewable Energy Laboratory Contact NREL About This Technology Technology Marketing Summary Quantum dot (QD) solids are a solution-processed, composite thin film semiconductor system that is being developed for optoelectronics (display technology, solid state lighting, next generation photovoltaics, photodetector application, etc.). For photovoltaics, in addition to

  6. Scalable quantum computer architecture with coupled donor-quantum dot qubits

    DOE Patents [OSTI]

    Schenkel, Thomas; Lo, Cheuk Chi; Weis, Christoph; Lyon, Stephen; Tyryshkin, Alexei; Bokor, Jeffrey

    2014-08-26

    A quantum bit computing architecture includes a plurality of single spin memory donor atoms embedded in a semiconductor layer, a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, wherein a first voltage applied across at least one pair of the aligned quantum dot and donor atom controls a donor-quantum dot coupling. A method of performing quantum computing in a scalable architecture quantum computing apparatus includes arranging a pattern of single spin memory donor atoms in a semiconductor layer, forming a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, applying a first voltage across at least one aligned pair of a quantum dot and donor atom to control a donor-quantum dot coupling, and applying a second voltage between one or more quantum dots to control a Heisenberg exchange J coupling between quantum dots and to cause transport of a single spin polarized electron between quantum dots.

  7. Effect of carrier dynamics and temperature on two-state lasing in semiconductor quantum dot lasers

    SciTech Connect (OSTI)

    Korenev, V. V. Savelyev, A. V.; Zhukov, A. E.; Omelchenko, A. V.; Maximov, M. V.

    2013-10-15

    It is analytically shown that the both the charge carrier dynamics in quantum dots and their capture into the quantum dots from the matrix material have a significant effect on two-state lasing phenomenon in quantum dot lasers. In particular, the consideration of desynchronization in electron and hole capture into quantum dots allows one to describe the quenching of ground-state lasing observed at high injection currents both qualitatevely and quantitatively. At the same time, an analysis of the charge carrier dynamics in a single quantum dot allowed us to describe the temperature dependences of the emission power via the ground- and excited-state optical transitions of quantum dots.

  8. Thick-shell nanocrystal quantum dots (Patent) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Patent: Thick-shell nanocrystal quantum dots Citation Details In-Document Search Title: Thick-shell nanocrystal quantum dots You are accessing a document from the Department of...

  9. R&D Magazine: Windows into Solar Power Sources with Quantum Dots

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    R&D Magazine: Windows into Solar Power Sources with Quantum Dots August 30, 2015 R&D Magazine: Windows into Solar Power Sources with Quantum Dots A luminescent solar concentrator...

  10. Density-Dependent Carrier Dynamics in a Quantum Dots-in-a-Well...

    Office of Scientific and Technical Information (OSTI)

    Dynamics in a Quantum Dots-in-a-Well Heterostructure. Citation Details In-Document Search Title: Density-Dependent Carrier Dynamics in a Quantum Dots-in-a-Well Heterostructure. ...

  11. Surface Induced Magnetism in Quantum Dots

    SciTech Connect (OSTI)

    Meulenberg, R W; Lee, J I

    2009-08-20

    The study of nanometer sized semiconductor crystallites, also known as quantum dots (QDs), has seen rapid advancements in recent years in scientific disciplines ranging from chemistry, physics, biology, materials science, and engineering. QD materials of CdSe, ZnSe, InP, as well as many others, can be prepared in the size range of 1-10 nm producing uniform, nearly monodisperse materials that are typically coated with organic molecules [1-3]. The strength of charge carrier confinement, which dictates the size-dependent properties, in these QDs depends on the nature of the material and can be correlated to the Bohr radius for the system of interest. For instance, the Bohr radius for CdSe is {approx} 5 nm, while in the more covalent structure of InP, the Bohr radius approaches {approx} 10 nm. The study of CdSe QDs has been particularly extensive during the last decade because they exhibit unique and tunable optical properties and are readily synthesized with high-crystallinity and narrow size dispersions. Although the core electronic properties of CdSe are explained in terms of the quantum confinement model, experimental efforts to elucidate the surface structure of these materials have been limited. Typically, colloidal CdSe QDs are coated with an organic surfactant, which typically consists of an organo-phosphine, -thiol, or -amine, that has the function of energetically relaxing defect states via coordination to partially coordinated surface atoms. The organic surfactant also acts to enhance carrier confinement and prevent agglomeration of the particles. Chemically, it has been shown that the bonding of the surfactant to the CdSe QD occurs through Cd atoms resulting cleavage of the Se atoms and formation of a Cd-rich (i.e. non-stoichiometric) particle [5].

  12. Out-of-Equilibrium Kondo Effect in Double Quantum Dots

    SciTech Connect (OSTI)

    Aguado, Ramon; Langreth, David C.

    2000-08-28

    The out-of-equilibrium transport properties of a double quantum dot system in the Kondo regime are studied theoretically by means of a two-impurity Anderson Hamiltonian with interimpurity hopping. The Hamiltonian is solved by means of a nonequilibrium generalization of the slave-boson mean-field theory. It is demonstrated that measurements of the differential conductance dI/dV , for appropriate values of voltages and tunneling couplings, can give a direct observation of the coherent superposition between the many-body Kondo states of each dot. For large voltages and arbitrarily large interdot tunneling, there is a critical voltage above which the physical behavior of the system again resembles that of two decoupled quantum dots. (c) 2000 The American Physical Society.

  13. Operational guidance for using DOT-6M/2R packaging

    SciTech Connect (OSTI)

    Kelly, D.L.; Hummer, J.H.

    1994-03-01

    The purpose of this paper is to describe a new US Department of Energy (DOE), Transportation Management Division task to create a US Department of Transportation (DOT) Specification 6M/2R packaging configuration user`s guide. The need for a user`s guide was identified because the DOT-6M/2R packaging configuration is widely used by DOE site contractors, and DOE receives many questions about the approved packaging configurations. Currently, two DOE organizations have the authority to approve new DOT-6M/2R configurations. For Defense Programs, the Transportation and Packaging Safety Division (EH-332) administers the program. For Environmental Restoration and Waste Management, the Transportation Management Division (EM-261) administers the program.

  14. Quasi-periodic quantum dot arrays produced by electrochemical synthesis

    SciTech Connect (OSTI)

    Bandyopadhyay, S.; Miller, A.E.; Yue, D.F.; Banerjee, G.; Ricker, R.E.; Jones, S.; Eastman, J.A.; Baugher, E.; Chandrasekhar, M.

    1994-06-01

    We discuss a ``gentle`` electrochemical technique for fabricating quasi-periodic quantum dot arrays. The technique exploits a self-organizing phenomenon to produce quasi-periodic arrangement of dots and provides excellent control over dot size and interdot spacing. Unlike conventional nanolithography, it does not cause radiation damage to the structures during exposure to pattern delineating beams (e-beam, ion-beam or x-ray). Moreover, it does not require harsh processing steps like reactive ion etching, offers a minimum feature size of {approximately}40 {angstrom}, allows the fabrication of structures on nonplanar surfaces (e.g. spherical or cylindrical substrates), is amenable to mass production (millions of wafers can be processed simultaneously) and is potentially orders of magnitude cheaper than conventional nanofabrication. In this paper, we describe our initial results and show the promise of this technique for low-cost and high-yield nanosynthesis.

  15. DOT-7A Type A packaging design guide

    SciTech Connect (OSTI)

    Kelly, D.L.

    1995-01-23

    The purpose of this Design Guide is to provide instruction for designing a U.S. Department of Transportation Specification 7A (DOT-7A) Type A packaging. Another purpose for this Design Guide is to support the evaluation and testing activities that are performed on new designs by a U.S. Department of Energy (DOE) test facility. This evaluation and testing program is called the DOT-7A Program. When an applicant has determined that a DOT-7A packaging is needed and not commercially available, a design may be created according to this document. The design should include a packaging drawing, specifications, analysis report, operating instructions, and a Packaging Qualification Checklist; all of which should be forwarded to a DOE/HQ approved test facility for evaluation and testing. This report is being submitted through the Engineering Documentation System so that it may be used for reference and information purposes.

  16. A prototype silicon double quantum dot with dispersive microwave readout

    SciTech Connect (OSTI)

    Schmidt, A. R. Henry, E.; Namaan, O.; Siddiqi, I.; Lo, C. C.; Wang, Y.-T.; Bokor, J.; Yablonovitch, E.; Li, H.; Greenman, L.; Whaley, K. B.; Schenkel, T.

    2014-07-28

    We present a unique design and fabrication process for a lateral, gate-confined double quantum dot in an accumulation mode metal-oxide-semiconductor (MOS) structure coupled to an integrated microwave resonator. All electrostatic gates for the double quantum dot are contained in a single metal layer, and use of the MOS structure allows for control of the location of the two-dimensional electron gas via the location of the accumulation gates. Numerical simulations of the electrostatic confinement potential are performed along with an estimate of the coupling of the double quantum dot to the microwave resonator. Prototype devices are fabricated and characterized by transport measurements of electron confinement and reflectometry measurements of the microwave resonator.

  17. Self-organized formation of quantum dots of a material on a substrate

    DOE Patents [OSTI]

    Zhang, Zhenyu (232 Long Bow Rd., Knoxville, TN 37922); Wendelken, John F. (925 Suwanee Rd., Knoxville, TN 37923); Chang, Ming-Che (F4-2, No. 178 Sec 5 Minsheng East Rd., Taipei, TW); Pai, Woei Wu (1F, No. 17, Alley 11, Lane 202, Ming Chyuan Rd., Pan Chou City, Taipei County, TW)

    2001-01-01

    Systems and methods are described for fabricating arrays of quantum dots. A method for making a quantum dot device, includes: forming clusters of atoms on a substrate; and charging the clusters of atoms such that the clusters of atoms repel one another. The systems and methods provide advantages because the quantum dots can be ordered with regard to spacing and/or size.

  18. Analysis of the efficiency of intermediate band solar cells based on quantum dot supercrystals

    SciTech Connect (OSTI)

    Heshmati, S; Golmohammadi, S; Abedi, K; Taleb, H

    2014-03-28

    We have studied the influence of the quantum-dot (QD) width and the quantum-dot conduction band (QD-CB) offset on the efficiency of quantum-dot intermediate band solar cells (QD-IBSCs). Simulation results demonstrate that with increasing QD-CB offset and decreasing QD width, the maximum efficiency is achieved. (laser applications and other topics in quantum electronics)

  19. Quantum-dot based nanothermometry in optical plasmonic recording media

    SciTech Connect (OSTI)

    Maestro, Laura Martinez; Zhang, Qiming; Li, Xiangping; Gu, Min; Jaque, Daniel

    2014-11-03

    We report on the direct experimental determination of the temperature increment caused by laser irradiation in a optical recording media constituted by a polymeric film in which gold nanorods have been incorporated. The incorporation of CdSe quantum dots in the recording media allowed for single beam thermal reading of the on-focus temperature from a simple analysis of the two-photon excited fluorescence of quantum dots. Experimental results have been compared with numerical simulations revealing an excellent agreement and opening a promising avenue for further understanding and optimization of optical writing processes and media.

  20. Optical control of the emission direction of a quantum dot

    SciTech Connect (OSTI)

    Luxmoore, I. J.; Wasley, N. A.; Fox, A. M.; Skolnick, M. S.; Ramsay, A. J.; Thijssen, A. C. T.; Oulton, R.; Hugues, M.; CNRS-CRHEA, rue Bernard Grgory, 06560 Valbonne

    2013-12-09

    Using the helicity of a non-resonant excitation laser, control over the emission direction of an InAs/GaAs quantum dot is demonstrated. The quantum dot is located off-center in a crossed-waveguide structure, such that photons of opposite circular polarization are emitted into opposite waveguide directions. By preferentially exciting spin-polarized excitons, the direction of emission can therefore be controlled. The directional control is quantified by using the ratio of the intensity of the light coupled into the two waveguides, which reaches a maximum of 35%.

  1. Jefferson Lab announces two Fall Science Series lectures; examine evidence

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of an ancient supernova, the magic of Harry Potter | Jefferson Lab lectures; examine evidence of an ancient supernova, the magic of Harry Potter September 26, 2006 Remains of a star going supernova and a physics discussion of the magic found in Harry Potter books are the topics of Jefferson Lab's Fall Science Series. The first presentation, "When Stars Attack!" is Oct. 17 and features Dr. Brian Fields from the University of Illinois. He will explain how he is using radioactive sea

  2. Increased InAs quantum dot size and density using bismuth as a surfactant

    SciTech Connect (OSTI)

    Dasika, Vaishno D.; Krivoy, E. M.; Nair, H. P.; Maddox, S. J.; Park, K. W.; Yu, E. T.; Bank, S. R.; Jung, D.; Lee, M. L.

    2014-12-22

    We have investigated the growth of self-assembled InAs quantum dots using bismuth as a surfactant to control the dot size and density. We find that the bismuth surfactant increases the quantum dot density, size, and uniformity, enabling the extension of the emission wavelength with increasing InAs deposition without a concomitant reduction in dot density. We show that these effects are due to bismuth acting as a reactive surfactant to kinetically suppress the surface adatom mobility. This mechanism for controlling quantum dot density and size has the potential to extend the operating wavelength and enhance the performance of various optoelectronic devices.

  3. New Los Alamos approach may be key to quantum dot solar cells with real

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    gains in efficiency Quantum dot solar cells with real gains in efficiency New Los Alamos approach may be key to quantum dot solar cells with real gains in efficiency Researchers have demonstrated an almost four-fold boost of the carrier multiplication yield with nanoengineered quantum dots. June 18, 2014 Core/shell PbSe/CdSe quantum dots (a) and a carrier multiplication (CM) pathway (b) in these nano structures. (a) Transmission electron microscopy image of thick-shell PbSe/CdSe quantum dots

  4. Structure of droplet-epitaxy-grown InAs/GaAs quantum dots

    SciTech Connect (OSTI)

    Cohen, Eyal; Yochelis, Shira; Westreich, Ohad; Shusterman, Sergey; Kumah, Divine P.; Clarke, Roy; Yacoby, Yizhak; Paltiel, Yossi

    2011-09-06

    We have used a direct x-ray phasing method, coherent Bragg rod analysis, to obtain sub-angstrom resolution electron density maps of the InAs/GaAs dot system. The dots were grown by the droplet heteroepitaxy (DHE) technique and their structural and compositional properties are compared with those of dots grown by the strain-driven Stranski-Krastanov method. Our results show that the Ga diffusion into the DHE-grown dots is somewhat larger; however, other characteristics such as the composition of the dots uppermost layers, the interlayer spacing, and the bowing of the atomic layers are similar.

  5. Intermediate-band photosensitive device with quantum dots having tunneling barrier embedded in organic matrix

    DOE Patents [OSTI]

    Forrest, Stephen R. (Ann Arbor, MI)

    2008-08-19

    A plurality of quantum dots each have a shell. The quantum dots are embedded in an organic matrix. At least the quantum dots and the organic matrix are photoconductive semiconductors. The shell of each quantum dot is arranged as a tunneling barrier to require a charge carrier (an electron or a hole) at a base of the tunneling barrier in the organic matrix to perform quantum mechanical tunneling to reach the respective quantum dot. A first quantum state in each quantum dot is between a lowest unoccupied molecular orbital (LUMO) and a highest occupied molecular orbital (HOMO) of the organic matrix. Wave functions of the first quantum state of the plurality of quantum dots may overlap to form an intermediate band.

  6. Approaches to Future Generation Photovoltaics and Solar Fuels: Quantum Dots, Arrays, and Quantum Dot Solar Cells

    SciTech Connect (OSTI)

    Semonin, O.; Luther, J.; Beard, M.; Johnson, J.; Gao, J.; Nozik, A.

    2012-01-01

    One potential, long-term approach to more efficient and lower cost future generation solar cells for solar electricity and solar fuels is to utilize the unique properties of quantum dots (QDs) to control the relaxation pathways of excited states to enhance multiple exciton generation (MEG). We have studied MEG in close-packed PbSe QD arrays where the QDs are electronically coupled in the films and thus exhibit good transport while still maintaining quantization and MEG. We have developed simple, all-inorganic solution-processable QD solar cells that produce large short-circuit photocurrents and power conversion efficiencies above 5% via nanocrystalline p-n junctions. These solar cells show QYs for photocurrent that exceed 100% in the photon energy regions where MEG is possible; the photocurrent MEG QYs as a function of photon energy match those determined via time-resolved spectroscopy Recent analyses of the major effect of MEG combined with solar concentration on the conversion efficiency of solar cells will also be discussed.

  7. Simulation of quantum dots size and spacing effect for intermediate band solar cell application based on InAs quantum dots arrangement in GaAs

    SciTech Connect (OSTI)

    Hendra, P. I. B. Rahayu, F. Darma, Y.

    2014-03-24

    Intermediate band solar cell (IBSC) has become a promising technology in increasing solar cell efficiency. In this work we compare absorption coefficient profile between InAs quantum dots with GaAs bulk. We calculate the efficiency of GaAs bulk and GaAs doped with 2, 5, and 10 nm InAs quantum dot. Effective distances in quantum dot arrangement based on electron tunneling consideration were also calculated. We presented a simple calculation method with low computing power demand. Results showed that arrangement of quantum dot InAs in GaAs can increase solar cell efficiency from 23.9 % initially up to 60.4%. The effective distance between two quantum dots was found 2 nm in order to give adequate distance to prevent electron tunneling and wave functions overlap.

  8. Facile synthesis and photoluminescence mechanism of graphene quantum dots

    SciTech Connect (OSTI)

    Yang, Ping; Zhou, Ligang; Zhang, Shenli; Pan, Wei Shen, Wenzhong; Wan, Neng

    2014-12-28

    We report a facile hydrothermal synthesis of intrinsic fluorescent graphene quantum dots (GQDs) with two-dimensional morphology. This synthesis uses glucose, concentrate sulfuric acid, and deionized water as reagents. Concentrated sulfuric acid is found to play a key role in controlling the transformation of as-prepared hydrothermal products from amorphous carbon nanodots to well-crystallized GQDs. These GQDs show typical absorption characteristic for graphene, and have nearly excitation-independent ultraviolet and blue intrinsic emissions. Temperature-dependent PL measurements have demonstrated strong electron-electron scattering and electron-phonon interactions, suggesting a similar temperature behavior of GQDs to inorganic semiconductor quantum dots. According to optical studies, the ultraviolet emission is found to originate from the recombination of electron-hole pairs localized in the C=C bonds, while the blue emission is from the electron transition of sp{sup 2} domains.

  9. Resonant scattering of surface plasmon polaritons by dressed quantum dots

    SciTech Connect (OSTI)

    Huang, Danhong; Cardimona, Dave; Easter, Michelle; Gumbs, Godfrey; Maradudin, A. A.; Lin, Shawn-Yu; Zhang, Xiang

    2014-06-23

    The resonant scattering of surface plasmon-polariton waves (SPP) by embedded semiconductor quantum dots above the dielectric/metal interface is explored in the strong-coupling regime. In contrast to non-resonant scattering by a localized dielectric surface defect, a strong resonant peak in the spectrum of the scattered field is predicted that is accompanied by two side valleys. The peak height depends nonlinearly on the amplitude of SPP waves, reflecting the feedback dynamics from a photon-dressed electron-hole plasma inside the quantum dots. This unique behavior in the scattered field peak strength is correlated with the occurrence of a resonant dip in the absorption spectrum of SPP waves due to the interband photon-dressing effect. Our result on the scattering of SPP waves may be experimentally observable and applied to spatially selective illumination and imaging of individual molecules.

  10. Optical, electronic, and structural properties of uncoupled and close-packed arrays of InP quantum dots

    SciTech Connect (OSTI)

    Micic, O.I.; Jones, K.M.; Cahill, A.; Nozik, A.J.

    1998-12-03

    Solid films consisting of close-packed arrays of InP quantum dots have been prepared by slowly evaporating colloidal solutions of InP quantum dots. The diameters of the quantum dots were controlled to be between about 30 to 60 {angstrom}; size-selective precipitation yielded a size distribution of about 10% about the mean diameter. The arrays show regions of hexagonal order, as well as disordered regions. Oxide layers can form irreversibly on the quantum dot surface and limit the effectiveness of the size-selective precipitation. Photoluminescence spectra obtained from close-packed films of InP quantum dots formed from quantum dots with a single mean diameter and from a mixture of two quantum dot sizes show that energy transfer occurs from the photoexcited smaller quantum dots to the larger quantum dots. The efficiency of this energy transfer process is high.

  11. Computational models for the berry phase in semiconductor quantum dots

    SciTech Connect (OSTI)

    Prabhakar, S. Melnik, R. V. N.; Sebetci, A.

    2014-10-06

    By developing a new model and its finite element implementation, we analyze the Berry phase low-dimensional semiconductor nanostructures, focusing on quantum dots (QDs). In particular, we solve the Schrdinger equation and investigate the evolution of the spin dynamics during the adiabatic transport of the QDs in the 2D plane along circular trajectory. Based on this study, we reveal that the Berry phase is highly sensitive to the Rashba and Dresselhaus spin-orbit lengths.

  12. QCAD simulation and optimization of semiconductor double quantum dots

    SciTech Connect (OSTI)

    Nielsen, Erik; Gao, Xujiao; Kalashnikova, Irina; Muller, Richard Partain; Salinger, Andrew Gerhard; Young, Ralph Watson

    2013-12-01

    We present the Quantum Computer Aided Design (QCAD) simulator that targets modeling quantum devices, particularly silicon double quantum dots (DQDs) developed for quantum qubits. The simulator has three di erentiating features: (i) its core contains nonlinear Poisson, e ective mass Schrodinger, and Con guration Interaction solvers that have massively parallel capability for high simulation throughput, and can be run individually or combined self-consistently for 1D/2D/3D quantum devices; (ii) the core solvers show superior convergence even at near-zero-Kelvin temperatures, which is critical for modeling quantum computing devices; (iii) it couples with an optimization engine Dakota that enables optimization of gate voltages in DQDs for multiple desired targets. The Poisson solver includes Maxwell- Boltzmann and Fermi-Dirac statistics, supports Dirichlet, Neumann, interface charge, and Robin boundary conditions, and includes the e ect of dopant incomplete ionization. The solver has shown robust nonlinear convergence even in the milli-Kelvin temperature range, and has been extensively used to quickly obtain the semiclassical electrostatic potential in DQD devices. The self-consistent Schrodinger-Poisson solver has achieved robust and monotonic convergence behavior for 1D/2D/3D quantum devices at very low temperatures by using a predictor-correct iteration scheme. The QCAD simulator enables the calculation of dot-to-gate capacitances, and comparison with experiment and between solvers. It is observed that computed capacitances are in the right ballpark when compared to experiment, and quantum con nement increases capacitance when the number of electrons is xed in a quantum dot. In addition, the coupling of QCAD with Dakota allows to rapidly identify which device layouts are more likely leading to few-electron quantum dots. Very efficient QCAD simulations on a large number of fabricated and proposed Si DQDs have made it possible to provide fast feedback for design comparison and optimization.

  13. Renewable Energy: Solar Fuels - Gordon Research Conference (Lucca...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sun, Feb 28, 2016 9:00am 09:00 Fri, Mar 4, 2016 5:00pm 17:00 Renaissance Tuscany Il Ciocco Lucca Italy Harry Atwater, "Artficial Photosynthesis Progress and Prospects" Giulia ...

  14. Spring Valley, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Hide Map This article is a stub. You can help OpenEI by expanding it. Spring Valley is a city in Harris County, Texas. It falls under Texas's 7th congressional...

  15. Technical Standards Managers

    Broader source: Energy.gov (indexed) [DOE]

    Phone: (202) 586-7963 Fax: (202) 586-3859 stephen.lucke @nnsa.doe.gov DOE-NFO Sheila M. Harris TSM U.S. Department of Energy Centerra Nevada DOENNSANevada Field O ce MS 576...

  16. The Y-12 Times, June 2009, Employee Newsletter

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Amy Alley: alleyab@y12.doe.gov Heidi Spurling: spurlinghw@y12.doe.gov LayoutDesign Lisa Harris Contributors Ellen Boatner Amanda Byrge Ken Davis Kathy Fahey Stuart Hames W H A T...

  17. Synthetic and Mechanistic Chemistry

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    22(3), 189-198 (2009). Ramesh R. Kale, Harshini Mukundan, Dominique N. Price, J. Foster Harris, Daniel M. Lewallen, Basil I. Swanson, Jurgen G. Schmidt, and Suri S. Iyer,...

  18. Organization Amount Volunteer

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    0 Nichols, B etsy --- 1 00 Hilltopper B asketball A cademy 1550 Carver, R endell --- 2 50 Harris, R obert --- 5 00 Logan, T arah --- 2 50 Peterson, D onald ( Pete) --- 5 00...

  19. Before the House Subcommittee on Energy and Power, Committee...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Diversity Before the House Subcommittee on Energy and Power, Committee on Energy and Commerce PDF icon 9-17-14LaDorisHarris FT HEC.pdf More Documents & Publications Minorities...

  20. Inspiring Girls to Explore STEM Careers in Charleston, SC | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    with her inspirational keynote speech. "You are amazing," Harris said to the girls. "It's important for you to know that as we take our journey - dreaming big makes it happen." ...

  1. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Filter by Author VESPER, DJ, Edenborn, Harry (1) Save Results Save this search to My Library Excel (limit 2000) CSV (limit 5000) XML (limit 5000) Have feedback or suggestions for a ...

  2. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Sullivan, John P (4) Tyliszczak, Tolek (4) Fenton, Kyle R. (3) Harris, Charles Thomas (3) Huang, Jian Yu (3) Kotula, Paul G. (3) Leung, Kevin (3) Liu, Xiao Hua (3) Liu, Yang (3) ...

  3. Friendswood, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    You can help OpenEI by expanding it. Friendswood is a city in Galveston County and Harris County, Texas. It falls under Texas's 14th congressional district and Texas's 22nd...

  4. Missouri City, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    You can help OpenEI by expanding it. Missouri City is a city in Fort Bend County and Harris County, Texas. It falls under Texas's 9th congressional district and Texas's 22nd...

  5. League City, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    You can help OpenEI by expanding it. League City is a city in Galveston County and Harris County, Texas. It falls under Texas's 14th congressional district and Texas's 22nd...

  6. Tomball, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Map This article is a stub. You can help OpenEI by expanding it. Tomball is a city in Harris County, Texas. It falls under Texas's 10th congressional district and Texas's 8th...

  7. Jacinto City, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    This article is a stub. You can help OpenEI by expanding it. Jacinto City is a city in Harris County, Texas. It falls under Texas's 29th congressional district.12 References...

  8. Jersey Village, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    article is a stub. You can help OpenEI by expanding it. Jersey Village is a city in Harris County, Texas. It falls under Texas's 7th congressional district.12 References ...

  9. Nassau Bay, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    This article is a stub. You can help OpenEI by expanding it. Nassau Bay is a city in Harris County, Texas. It falls under Texas's 22nd congressional district.12 References...

  10. Highlands, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    a stub. You can help OpenEI by expanding it. Highlands is a census-designated place in Harris County, Texas.1 References US Census Bureau 2005 Place to 2006 CBSA Retrieved...

  11. Hunters Creek Village, Texas: Energy Resources | Open Energy...

    Open Energy Info (EERE)

    is a stub. You can help OpenEI by expanding it. Hunters Creek Village is a city in Harris County, Texas. It falls under Texas's 7th congressional district.12 References ...

  12. Seabrook, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    OpenEI by expanding it. Seabrook is a city in Chambers County and Galveston County and Harris County, Texas. It falls under Texas's 14th congressional district and Texas's 22nd...

  13. Shoreacres, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    stub. You can help OpenEI by expanding it. Shoreacres is a city in Chambers County and Harris County, Texas. It falls under Texas's 14th congressional district and Texas's 22nd...

  14. Pearland, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    OpenEI by expanding it. Pearland is a city in Brazoria County and Fort Bend County and Harris County, Texas. It falls under Texas's 14th congressional district and Texas's 22nd...

  15. Cinco Ranch, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    by expanding it. Cinco Ranch is a census-designated place in Fort Bend County and Harris County, Texas.1 References US Census Bureau 2005 Place to 2006 CBSA Retrieved...

  16. Barrett, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    a stub. You can help OpenEI by expanding it. Barrett is a census-designated place in Harris County, Texas.1 References US Census Bureau 2005 Place to 2006 CBSA Retrieved...

  17. Katy, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    is a stub. You can help OpenEI by expanding it. Katy is a city in Fort Bend County and Harris County and Waller County, Texas. It falls under Texas's 14th congressional district...

  18. Atascocita, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    stub. You can help OpenEI by expanding it. Atascocita is a census-designated place in Harris County, Texas.1 References US Census Bureau 2005 Place to 2006 CBSA Retrieved...

  19. Morgan's Point, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    article is a stub. You can help OpenEI by expanding it. Morgan's Point is a city in Harris County, Texas. It falls under Texas's 2nd congressional district.12 References ...

  20. West University Place, Texas: Energy Resources | Open Energy...

    Open Energy Info (EERE)

    is a stub. You can help OpenEI by expanding it. West University Place is a city in Harris County, Texas. It falls under Texas's 7th congressional district.12 References ...

  1. Hilshire Village, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    article is a stub. You can help OpenEI by expanding it. Hilshire Village is a city in Harris County, Texas. It falls under Texas's 7th congressional district.12 References ...

  2. South Houston, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    article is a stub. You can help OpenEI by expanding it. South Houston is a city in Harris County, Texas. It falls under Texas's 29th congressional district.12 References...

  3. Aldine, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    is a stub. You can help OpenEI by expanding it. Aldine is a census-designated place in Harris County, Texas.1 References US Census Bureau 2005 Place to 2006 CBSA Retrieved...

  4. Osceola County, Iowa: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Zone Number 6 Climate Zone Subtype A. Places in Osceola County, Iowa Ashton, Iowa Harris, Iowa Melvin, Iowa Ocheyedan, Iowa Sibley, Iowa Retrieved from "http:en.openei.org...

  5. Southside Place, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    article is a stub. You can help OpenEI by expanding it. Southside Place is a city in Harris County, Texas. It falls under Texas's 7th congressional district.12 References ...

  6. Bunker Hill Village, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    is a stub. You can help OpenEI by expanding it. Bunker Hill Village is a city in Harris County, Texas. It falls under Texas's 7th congressional district.12 References ...

  7. Pine Mountain, Georgia: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    article is a stub. You can help OpenEI by expanding it. Pine Mountain is a town in Harris County and Meriwether County, Georgia. It falls under Georgia's 3rd congressional...

  8. Humble, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Map This article is a stub. You can help OpenEI by expanding it. Humble is a city in Harris County, Texas. It falls under Texas's 2nd congressional district and Texas's 18th...

  9. Piney Point Village, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    is a stub. You can help OpenEI by expanding it. Piney Point Village is a city in Harris County, Texas. It falls under Texas's 7th congressional district.12 References ...

  10. Hedwig Village, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    article is a stub. You can help OpenEI by expanding it. Hedwig Village is a city in Harris County, Texas. It falls under Texas's 7th congressional district.12 References ...

  11. Stafford, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    stub. You can help OpenEI by expanding it. Stafford is a city in Fort Bend County and Harris County, Texas. It falls under Texas's 9th congressional district and Texas's 22nd...

  12. Baytown, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    a stub. You can help OpenEI by expanding it. Baytown is a city in Chambers County and Harris County, Texas. It falls under Texas's 14th congressional district and Texas's 2nd...

  13. Waller, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Map This article is a stub. You can help OpenEI by expanding it. Waller is a city in Harris County and Waller County, Texas. It falls under Texas's 10th congressional...

  14. Channelview, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    stub. You can help OpenEI by expanding it. Channelview is a census-designated place in Harris County, Texas.1 References US Census Bureau 2005 Place to 2006 CBSA Retrieved...

  15. Cloverleaf, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    stub. You can help OpenEI by expanding it. Cloverleaf is a census-designated place in Harris County, Texas.1 References US Census Bureau 2005 Place to 2006 CBSA Retrieved...

  16. Mission Bend, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    by expanding it. Mission Bend is a census-designated place in Fort Bend County and Harris County, Texas.1 References US Census Bureau 2005 Place to 2006 CBSA Retrieved...

  17. Pasadena, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Map This article is a stub. You can help OpenEI by expanding it. Pasadena is a city in Harris County, Texas. It falls under Texas's 22nd congressional district and Texas's 29th...

  18. Crosby, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    is a stub. You can help OpenEI by expanding it. Crosby is a census-designated place in Harris County, Texas.1 References US Census Bureau 2005 Place to 2006 CBSA Retrieved...

  19. El Lago, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Map This article is a stub. You can help OpenEI by expanding it. El Lago is a city in Harris County, Texas. It falls under Texas's 22nd congressional district.12 References...

  20. Remembering Fukushima: PNNL Monitors Radiation from Nuclear Disaster

    SciTech Connect (OSTI)

    Miley, Harry

    2014-03-07

    Senior Scientist Harry Miley describes how his work in ultra-trace, nuclear detection technology picked up the first reading of radiological materials over the U.S. following the nuclear power plant explosion in Japan.

  1. SFA 2.0- Metabolic Potential

    SciTech Connect (OSTI)

    Banfield, Jill; Beller, Harry

    2015-02-17

    Berkeley Lab Earth Scientists Jill Banfield and Harry Beller explain the Sustainable Systems SFA 2.0 project's research on metabolic potentialor how metabolic lifestyles of microbial communities modulate in response to as well as influence environmental change.

  2. EIS-0443: Record of Decision | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    235 miles of 500- kilovolt (kV) transmission line. SWIP-South would extend from Harry Allen substation near Las Vegas, Nevada northward to the proposed Thirtymile Substation near...

  3. Steve Karsjen Public Affairs

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Imagine yourself watching different moving TV-like images on newspaper pages just like in Harry Potter films. And that's not all OLEDs might be used for. Someday they might make...

  4. Remembering Fukushima: PNNL Monitors Radiation from Nuclear Disaster

    ScienceCinema (OSTI)

    Miley, Harry

    2014-06-12

    Senior Scientist Harry Miley describes how his work in ultra-trace, nuclear detection technology picked up the first reading of radiological materials over the U.S. following the nuclear power plant explosion in Japan.

  5. Scalable superhydrophobic coatings based on fluorinated diatomaceous...

    Office of Scientific and Technical Information (OSTI)

    Authors: Polyzos, Georgios 1 ; Winter, Kyle O 1 ; Lance, Michael J 1 ; Meyer III, Harry M 1 ; Armstrong, Beth L 1 ; Schaeffer, Daniel A 1 ; Simpson, John T 1 ; ...

  6. Table 2. Ten Largest Plants by Generation Capacity, 2013

    U.S. Energy Information Administration (EIA) Indexed Site

    Inc",630 8,"John W Turk Jr Power Plant","Coal","Southwestern Electric Power Co",609 9,"Harry L. Oswald","Natural gas","Arkansas Electric Coop Corp",548 10,"Flint ...

  7. Energy Department Offers Conditional Commitment to Support Nevada...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    "I am glad to see economic recovery funding being used to put Nevadans to work on a project that will help us achieve energy independence," U.S. Senator Harry Reid said. "Northern ...

  8. Department of Energy Issues Loan Guarantee Supported by Recovery...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Nevada Senator Harry Reid. "Secretary Chu has been to Nevada many times and I thank him for recognizing the Silver State as a leader in developing these clean energy resources." ...

  9. Secretary Chu, Senator Reid Announce Department of Energy Conditional...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Project Expected to Create Over 300 Jobs and Produce Clean Geothermal Power Washington, D.C. - U.S. Energy Secretary Steven Chu and Senate Majority Leader Harry Reid today ...

  10. Secretary Chu, Senator Reid Announce Department of Energy Conditional...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Addthis Washington, D.C. - U.S. Energy Secretary Steven Chu and Senate Majority Leader Harry Reid today announced the offer of a conditional commitment to provide a partial ...

  11. GC Commits to Transparency on Nuclear Waste Fund Fee Adequacy Decisions

    Broader source: Energy.gov [DOE]

    Consistent with the Administration's commitment to transparency, DOE General Counsel Scott Blake Harris has decided that all future determinations as to the adequacy of the Nuclear Waste Fund fee...

  12. ALSNews Vol. 352

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    watch a video of a dendrite as it grows through a polymer membrane... Contact: Katherine Harry New See a list of all the summary slides for Industry @ ALS stories. The ALS...

  13. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Harris H" Name Name ORCID Search Authors Type: All BookMonograph ConferenceEvent Journal ... (DP) (United States) USDOE Office of ES&H, Office of Epidemiologic Studies (United ...

  14. Diverse Power- Energy Efficient New Construction Rebate Programs

    Broader source: Energy.gov [DOE]

    Diverse Power is a member-owned electric cooperative that provides electric service to customers in Troup, Harris, Heard, Meriwether, Muscogee and Coweta counties in Georgia. Diverse Power offers...

  15. EX PARTE COMMUNICATION MEETING WITH THE DEPARTMENT OF ENERGY

    Broader source: Energy.gov [DOE]

    Mr. Harris and Ms. Ginsberg discussed Part 810 of the Department’s rules, and the September 2011 Notice of Proposed Rulemaking (NOPR) and the July 2013 Supplemental Notice of Proposed Rulemaking ...

  16. Deer Park, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Hide Map This article is a stub. You can help OpenEI by expanding it. Deer Park is a city in Harris County, Texas. It falls under Texas's 22nd congressional district...

  17. Transport and Failure in Li-ion Batteries | Stanford Synchrotron...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in Li-ion Batteries Monday, February 13, 2012 - 1:30pm SSRL Conference Room 137-322 Stephen J. Harris, General Motors R&D While battery performance is well predicted by the...

  18. aec

    National Nuclear Security Administration (NNSA)

    blogkcp-operations-began-65-years-ago-today

    On Feb. 28, 1949,during Harry S. Truman's Presidency, the Bendix Corporation signed a prime contract to operate the...

  19. PNNL: About - Mission and Vision

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and courage, our staff deliver time and time again. Listen as featured Senior Scientist Harry Miley describes how his work in ultra-trace, nuclear detection technology picked up...

  20. TTW 09-2-10

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of the 2010. CBFO Manager Dave Moody briefed U.S. Senator Jeff Bingaman and Congressman Harry Teague on CBFO, contractor and American Recovery and Reinvestment Act activities at...

  1. aec | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    Blog Home aec aec KCP operations began 65 years ago today On Feb. 28, 1949, during Harry S. Truman's Presidency, the Bendix Corporation signed a prime contract to operate the...

  2. Secretary Chu and Senator Reid to Make Major Energy Announcement...

    Broader source: Energy.gov (indexed) [DOE]

    D.C. - U.S. Secretary Steven Chu and U.S. Senator Harry Reid will host a press conference call today, Tuesday, February 15 at 4:00 pm EST to make a major funding announcement...

  3. Microsoft PowerPoint - KCD Proj's Impact Fed Power_SWPA Conf...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    any operational changes to determine potential adverse impacts. BUILDING STRONG p Harry S. Truman Stilli B i R i Stilling Basin Repair S h d l Schedule 3 Jun -2 Jul: Contract...

  4. Scientists use plasma shaping to control turbulence in stellarators...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    regions of the highest strength shown in yellow. The MPX design is named for coauthors Harry Mynick and Neil Pomphrey of PPPL and Pavlos Xanthopoulos of the Max Planck Institute...

  5. Core Holes At Long Valley Caldera Geothermal Area (Chu, Et Al...

    Open Energy Info (EERE)

    H.R. Westrich (1990) The Magma Energy Program John B. Rundle, Charles R. Carrigan, Harry C. Hardee, William C. Luth (1986) Deep Drilling to the Magmatic Environment in Long...

  6. P

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    P hotonic d esign p rinciples f or ultrahigh---efficiency p hotovoltaics Harry A . A twater & A lbert P olman * For d ecades, s olar---cell efficiencies h ave remained b elow t he...

  7. Sandia PartnershipsOpps2.indd

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    1, 1949, when AT&T assumed management of the Laboratories at the request of President Harry Truman, who offered the company "an opportunity to render an exceptional service in...

  8. Truman's decision to drop the bomb to be discussed at 70th anniversary...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and why he made it Contact Nick Njegomir Communications Office (505) 667-5679 Email "Harry S. Truman considered the use of the atomic bomb on Japan among the most important and...

  9. DOE Extends Comment Period on Notice of Inquiry Under the Energy Independence and Security Act

    Broader source: Energy.gov [DOE]

    Today, in response to a formal request, General Counsel Scott Blake Harris approved a 30-day extension of the public comment period on DOE's Notice of Inquiry (75 FR 43945) soliciting comment on...

  10. DOE Extends Comment Period on Notice of Inquiry Under the Energy Independence and Security Act

    Broader source: Energy.gov [DOE]

    Today, in response to a formal request, General Counsel Scott Blake Harris approved a second and final extension of the public comment period to November 30, 2010 on DOEs Notice of Inquiry (75 FR...

  11. Stories of Discovery & Innovation: Beyond the Transistor | U...

    Office of Science (SC) Website

    in Energy Conversion (LMI), an EFRC led by Harry Atwater at Caltech and the Center for Energy Nanoscience (CEN), an EFRC led by Daniel Dapkus at the University of Southern ...

  12. When Green Turns to Gold | Photosynthetic Antenna Research Center

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    When Green Turns to Gold May 6, 2014 When Green Turns to Gold PARC Certificate Graduate Harry Bolson explains the importance of LEED Certification at WUSTL An error occurred. Try...

  13. PNNL: About PNNL - Research Fellows

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laskin L. Ruby Leung Yuehe Lin Jun Liu B. Peter McGrail Harry S. Miley William F. Morgan Karl T. Mueller ** Charles H. F. Peden Greg F. Piepel Philip Rasch Karin D. Rodland Kevin...

  14. PTL-5 From: Malin,Debra J - PTL-5

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    M - PFP-6; Clark,Harry W - PTL-5; Wilson,Scott K - PS-6; Olive,J Courtney - LP- 7; Larson,Cheryl A - PS-6 Subject: FW: PPC comments on EPP framework Attachments: PPC Comments -...

  15. The MAJORANA Project (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Leviner, L. 7 ; Luke, P. 4 ; MacMullin, S. 3 ; Marino, Michael G. 5 ; McDonald, Art B. 19 ; Mei, Dong-Ming 17 ; Miley, Harry S. 2 ; Myers, A. W. 5 ; Nomachi,...

  16. NETL F 451.1/1-1, Categorical Exclusion Designation Form

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    12121-6301-03 RPSEA Sugar Land, TX Clearview Subsea LLC, 16223 Park Row, Suite 175. Houston, Harris, Texas; Digitrol, Sao Paulo,Brazil; ProAnalysis, Bergen, Norway; JM Canty,...

  17. SREL Reprint #3038

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    the Savannah River Site J. C. Seaman1, B. B. Looney2, and M. K. Harris2 1Savannah River Ecology Laboratory, The University of Georgia, Aiken, SC 29802, USA 2Savannah River...

  18. 2014 Energy Campaign | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    HARRIS, 2014 VICE CHAIR This year marks the 53rd anniversary of the Combined Federal Campaign, the world's largest and most successful charity drive. And DOE employees have been a...

  19. Manhattan Project: Espionage and the Manhattan Project, 1940...

    Office of Scientific and Technical Information (OSTI)

    ... In 1950, the confession of Klaus Fuchs led the FBI to his handler, Harry Gold, who in turn led the FBI to David Greenglass. When confronted, Greenglass confessed, implicating his ...

  20. Non-Metals Workshop

    Broader source: Energy.gov [DOE]

    Presentation by Aaron Harris, Sandia National Laboratories, at the U.S. Department of Energy's Polymer and Composite Materials Meeting, held October 17-18, 2012, in Washington, D.C.

  1. SREL Reprint #3192

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in American Alligators (Alligator mississippiensis) at Savannah River, South Carolina, USA Andrew K. Davis1, Robert V. Horan, III2, Andrew M. Grosse2, Bess B. Harris2, Brian S....

  2. Electron Communities The Next Mars Rover What's Lacking with...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... fire or slam it into a brick wall, and it won't blow up," says R&D engineer Bert Harry, who has seen conven- tional explosives triggered by a mere waist- height drop to the floor. ...

  3. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Keith (1) Bryan Huff (1) Christina D,Moon (1) Christopher G,Knight (1) Christopher M,Thomas (1) David Williams (1) David,Harris (1) Douglas G. Patchen (1) Elizabeth,Saunders...

  4. 1

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ALAMOS, N.M., July 3, 2013-President Harry S. Truman's decision to use atomic bombs on Japan during World War II will be discussed in the next installment of Los Alamos National...

  5. Lead Slowing-Down Spectrometry for Spent Fuel Assay: FY12 Status...

    Office of Scientific and Technical Information (OSTI)

    ... R. C. ; Harris, Jason ; Imel, G. R. ; Kulisek, Jonathan A. ; O'Donnell, J. M. ; Stewart, T. ; Weltz, Adam Publication Date: 2012-10-01 OSTI Identifier: 1057843 Report ...

  6. USDA Feedstocks and Biofuels

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Chief Economist Office of Energy Policy and New Uses Harry S. Baumes, Ph. D. Director ... and Biofuels Office of the Chief Economist Office of Energy Policy and New Uses * ...

  7. USDA Feedstocks and Biofuels

    Broader source: Energy.gov [DOE]

    This is a presentation from the November 27, 2012, Sustainable Alternative Fuels Cost Workshop given by Harry S. Baumes, Director of the Office of Energy Policy and New Uses

  8. Density functional calculation of the structural and electronic properties of germanium quantum dots

    SciTech Connect (OSTI)

    Anas, M. M.; Gopir, G.

    2015-04-24

    We apply first principles density functional computational methods to study the structures, densities of states (DOS), and higher occupied molecular orbital (HOMO) lowest unoccupied molecular orbital (LUMO) gaps of selected free-standing Ge semiconductor quantum dots up to 1.8nm. Our calculations are performed using numerical atomic orbital approach where linear combination of atomic orbital was applied. The surfaces of the quantum dots was passivized by hydrogen atoms. We find that surface passivation does affect the electronic properties associated with the changes of surface state, electron localization, and the energy gaps of germanium nanocrystals as well as the confinement of electrons inside the quantum dots (QDs). Our study shows that the energy gaps of germanium quantum dots decreases with the increasing dot diameter. The size-dependent variations of the computed HOMO-LUMO gaps in our quantum dots model were found to be consistent with the effects of quantum confinement reported in others theoretical and experimental calculation.

  9. Excited-state spectroscopy of InP quantum dots

    SciTech Connect (OSTI)

    Bertram, D.; Micic, O.I.; Nozik, A.J.

    1998-02-01

    We have measured low-temperature size-selective photoluminescence excitation spectra of high-quality InP quantum dots prepared by collodial chemistry. A set of samples with mean emission energies in the range from 1.9 to 2.2 eV was investigated. All samples have a size distribution of about 10{percent}, resulting in an inhomogeneously broadened photoluminescence lineshape. Due to the finite size distribution, spectra were collected at different detection wavelengths to reveal the energies of the excited excitonic states. The size dependence of the quantization energies of InP nanoparticles was determined by measuring photoluminescence excitation at different detection energies within one sample. Up to eight excited-state transitions in a set of seven samples were observed, as the estimated quantum dot size was scanned from 1.8 to 4.0 nm. A comparison of the observed peaks with a six-band {bold k}{center_dot}{bold p} calculation is given. In contrast to the successful interpretation in the case of CdSe, no agreement between the calculated and the observed excited-state energies is achieved. {copyright} {ital 1998} {ital The American Physical Society}

  10. NREL Certifies First All-Quantum-Dot Photovoltaic Cell; Demonstrates Stability, Performance (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2011-02-01

    Researchers at the National Renewable Energy Laboratory (NREL) have certified the first all-quantum-dot photovoltaic cell, which was based on lead sulfide and demonstrated reasonable quantum dot solar cell performance for an initial efficiency measurement along with good stability. The certified open-circuit voltage of the quantum dot cell is greater than that possible from bulk lead sulfide because of quantum confinement.

  11. Size Dependence of Two-Photon Absorption in Semiconductor Quantum Dots

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Size Dependence of Two-Photon Absorption in Semiconductor Quantum Dots Citation Details In-Document Search Title: Size Dependence of Two-Photon Absorption in Semiconductor Quantum Dots Quantum confinement plays an important role in the optical properties of semiconductor quantum dots (QDs). In this work, we combine experiment and modeling to systematically investigate the size dependence of the degenerate two-photon absorption (TPA) of below-band-gap

  12. The impact of disorder on charge transport in three dimensional quantum dot

    Office of Scientific and Technical Information (OSTI)

    resonant tunneling structures (Journal Article) | SciTech Connect The impact of disorder on charge transport in three dimensional quantum dot resonant tunneling structures Citation Details In-Document Search Title: The impact of disorder on charge transport in three dimensional quantum dot resonant tunneling structures Efficient iso-entropic energy filtering of electronic waves can be realized through nanostructures with three dimensional confinement, such as quantum dot resonant tunneling

  13. Formation of long-range ordered quantum dots arrays in amorphous matrix by ion beam irradiation

    SciTech Connect (OSTI)

    Buljan, M.; Bogdanovic-Radovic, I.; Karlusic, M.; Desnica, U. V.; Radic, N.; Dubcek, P.; Drazic, G.; Salamon, K.; Bernstorff, S.; Holy, V.

    2009-08-10

    We demonstrate the production of a well ordered three-dimensional array of Ge quantum dots in amorphous silica matrix. The ordering is achieved by ion beam irradiation and annealing of a multilayer film. Structural analysis shows that quantum dots nucleate along the direction of the ion beam used for irradiation, while the mutual distance of the quantum dots is determined by the diffusion properties of the multilayer material rather than the distances between traces of ions that are used for irradiation.

  14. Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion

    Office of Scientific and Technical Information (OSTI)

    Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting Kundu, Janardan Los Alamos National Laboratory; Ghosh, Yagnaseni Los Alamos...

  15. Quantum-dot cluster-state computing with encoded qubits (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Quantum-dot cluster-state computing with encoded qubits Citation Details In-Document Search Title: Quantum-dot cluster-state computing with encoded qubits A class of architectures is advanced for cluster-state quantum computation using quantum dots. These architectures include using single and multiple dots as logical qubits. Special attention is given to supercoherent qubits introduced by Bacon et al. [Phys. Rev. Lett. 87, 247902 (2001)] for which we discuss the effects of

  16. Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion...

    Office of Scientific and Technical Information (OSTI)

    State Lighting Citation Details In-Document Search Title: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting You ...

  17. UltraDots Inc formely UltraPhotonics | Open Energy Information

    Open Energy Info (EERE)

    ) Place: Fremont, California Zip: CA 94539 Product: Nanotechnology company developing "quantum dot" technology for a range of energy, communications and medical applications....

  18. Charging dynamics of a floating gate transistor with site-controlled quantum dots

    SciTech Connect (OSTI)

    Maier, P. Hartmann, F.; Emmerling, M.; Schneider, C.; Hfling, S.; Kamp, M.; Worschech, L.

    2014-08-04

    A quantum dot memory based on a GaAs/AlGaAs quantum wire with site-controlled InAs quantum dots was realized by means of molecular beam epitaxy and etching techniques. By sampling of different gate voltage sweeps for the determination of charging and discharging thresholds, it was found that discharging takes place at short time scales of ?s, whereas several seconds of waiting times within a distinct negative gate voltage range were needed to charge the quantum dots. Such quantum dot structures have thus the potential to implement logic functions comprising charge and time dependent ingredients such as counting of signals or learning rules.

  19. Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion...

    Office of Scientific and Technical Information (OSTI)

    for LED based Solid State Lighting Citation Details In-Document Search Title: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based ...

  20. Cornell dots research collaboration leads to $10M cancer center > EMC2 News

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    > The Energy Materials Center at Cornell dots research collaboration leads to $10M cancer center September 24th, 2015 › Provided/Wiesner Lab A rendering of the molecular structure of a Cornell dot, which is smaller than 10 nanometers. Provided/Wiesner Lab A transmission electron microscope image of Cornell dots. C dots, which are injected into patients, are designed to either adhere to and light up cancer cells or quickly leave the body. Cornell University, in partnership with Memorial

  1. Thick-shell nanocrystal quantum dots (Patent) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Patent: Thick-shell nanocrystal quantum dots Citation Details In-Document Search Title: Thick-shell nanocrystal quantum dots Colloidal nanocrystal quantum dots comprising an inner core having an average diameter of at least 1.5 nm and an outer shell, where said outer shell comprises multiple monolayers, wherein at least 30% of the quantum dots have an on-time fraction of 0.80 or greater under continuous excitation conditions for a period of time of at least 10 minutes. Authors: Hollingsworth,

  2. Excited-State Relaxation in PbSe Quantum Dots

    SciTech Connect (OSTI)

    An, J. M.; Califano, M.; Franceschetti, A.; Zunger, A.

    2008-01-01

    In solids the phonon-assisted, nonradiative decay from high-energy electronic excited states to low-energy electronic excited states is picosecond fast. It was hoped that electron and hole relaxation could be slowed down in quantum dots, due to the unavailability of phonons energy matched to the large energy-level spacings ('phonon-bottleneck'). However, excited-state relaxation was observed to be rather fast ({le}1 ps) in InP, CdSe, and ZnO dots, and explained by an efficient Auger mechanism, whereby the excess energy of electrons is nonradiatively transferred to holes, which can then rapidly decay by phonon emission, by virtue of the densely spaced valence-band levels. The recent emergence of PbSe as a novel quantum-dot material has rekindled the hope for a slow down of excited-state relaxation because hole relaxation was deemed to be ineffective on account of the widely spaced hole levels. The assumption of sparse hole energy levels in PbSe was based on an effective-mass argument based on the light effective mass of the hole. Surprisingly, fast intraband relaxation times of 1-7 ps were observed in PbSe quantum dots and have been considered contradictory with the Auger cooling mechanism because of the assumed sparsity of the hole energy levels. Our pseudopotential calculations, however, do not support the scenario of sparse hole levels in PbSe: Because of the existence of three valence-band maxima in the bulk PbSe band structure, hole energy levels are densely spaced, in contradiction with simple effective-mass models. The remaining question is whether the Auger decay channel is sufficiently fast to account for the fast intraband relaxation. Using the atomistic pseudopotential wave functions of Pb{sub 2046}Se{sub 2117} and Pb{sub 260}Se{sub 249} quantum dots, we explicitly calculated the electron-hole Coulomb integrals and the P {yields} S electron Auger relaxation rate. We find that the Auger mechanism can explain the experimentally observed P {yields} S intraband decay time scale without the need to invoke any exotic relaxation mechanisms.

  3. IDC System Specification Document Version 1.1.

    SciTech Connect (OSTI)

    Harris, James M.; Lober, Randall R.

    2015-02-01

    This document contains the system specifications derived to satisfy the system requirements found in the IDC System Requirements Document for the IDC Reengineering Phase 2 project. Revisions Version Date Author/Team Revision Description Authorized by V1.0 12/2014 IDC Reengineering Project Team Initial delivery M. Harris V1.1 2/2015 IDC Reengineering Project Team Iteration I2 Review Comments M. Harris

  4. LSU EFRC - Center for Atomic Level Catalyst Design - Project

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nano-structured Catalysts for CO Activation space control Petra de Jongh Challa Kumar Ulrike Diebold Harry Bitter Krijn de Jong James J Spivey space control PI names & Affiliations: Petra E. de Jongh - Coordinator (U. Utrecht), Challa Kumar (LSU), Ulrike Diebold (TU-Vienna), Harry Bitter (U. Utrecht), Krijn de Jong (U. Utrecht), James J. Spivey (LSU), Gonzalo Prieto (U. Utrecht). space control Objective: To develop tools for the precise synthesis and characterization of 3D supported

  5. Light-Material Interactions in Energy Conversion - Energy Frontier Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Center (LMI-EFRC) Recordings of the presentations and panel discussions are available here for online viewing. Detailed abstracts of the presentations and bios for the speakers can be found here. Harry Atwater Photonic Design Principles for Ultrahigh-Efficiency Photovoltaics Harry Atwater, California Institute of Technology John Rogers Microscale Solar Cells for Macroscale Power Generation John Rogers, University of Illinois at Urbana-Champaign Eli Yablonovitch The Multi-Spectral

  6. Light-Material Interactions in Energy Conversion - Energy Frontier Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Center (LMI-EFRC) Lectures from the LMI-EFRC "Fundamental Challenges in Solar Energy Conversion" Workshop, July 7, 2010, Caltech Harry Atwater Introduction to the Workshop on Fundamental Challenges in Solar Energy Conversion Harry A. Atwater, Caltech Eli Yablonovitch Fundamental Limits to Light Absorption and Efficiency in Photovoltaics Eli Yablonovitch, University of California, Berkeley Richard Swanson Efficiency Limits and Cost Challenges in Photovoltaics Richard Swanson,

  7. JCAP News - JCAP

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    PAZ0080_v2.jpg JCAP News News & Events JCAP News JCAP Events Media Coverage News & Events JCAP News JCAP Events Talks Meetings & Workshops Media Coverage JCAP News + 2016 JANUARY 14, 2016 Caltech Interview with Prof. Marco Bernardi: Microscopic Materials. MORE + 2015 DECEMBER 16, 2015 JCAP Director Harry Atwater is named a fellow of the National Academy of Inventors for demonstrating "a prolific spirit of innovation...." More NOVEMBER 18, 2015 JCAP Director Harry Atwater

  8. Light-Material Interactions in Energy Conversion - Energy Frontier Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Center (LMI-EFRC) Harry Atwater welcome presentation Professor Harry Atwater gives the introductory presentation workshop audience Workshop participants in the Hameetman Auditorium Geoffrey Kinsey presentation Dr. Geoffrey Kinsey explores concentrator photovoltaics for high-efficiency photovoltaics. workshop Dr. Wladek Walukiewicz speaks with workshop participants. best poster award Lanfang Li, a Ph.D. Candidate in Prof. Ralph Nuzzo's group at UIUC and a member of the LMI-EFRC, won the Best

  9. Light-Material Interactions in Energy Conversion - Energy Frontier Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Center (LMI-EFRC) nuzzo LMI Deputy Director and UIUC Professor Ralph Nuzzo welcomes the audience. hofmann LMI Assistant Director Dr. Carrie Hofmann introduces the first speaker, LMI Director Prof. Harry Atwater. atwater Harry Atwater's presentation "Photonic Design Principles for Ultrahigh Efficiency Photovoltaics" John Rogers' presentation "Microscale Solar Cells for Macroscale Power Generation" eli Eli Yablonovitch's presentation "The Multi-Spectral Opto-Electronic

  10. Microsoft Word - Final EA for HARC Battleground.doc

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    9 FINAL ENVIRONMENTAL ASSESSMENT BATTLEGROUND ENERGY RECOVERY PROJECT HARRIS COUNTY, TEXAS U.S. DEPARTMENT OF ENERGY National Energy Technology Laboratory OCTOBER 2011 THIS PAGE INTENTIONALLY LEFT BLANK COVER SHEET Responsible Agency: U.S. Department of Energy Title: Final Environmental Assessment for the Battleground Energy Recovery Project (DOE/EA-1769) Location: Deer Park, Harris County, Texas Contact: William J. Gwilliam, Document Manager National Energy Technology Laboratory U.S. Department

  11. Before the House Subcommittee on Energy and Power, Committee on Energy and

    Energy Savers [EERE]

    Commerce | Department of Energy LaDoris Harris, Director of the Office of Economic Impact and Diversity Before the House Subcommittee on Energy and Power, Committee on Energy and Commerce PDF icon 9-17-14_LaDoris__Harris FT HEC.pdf More Documents & Publications Minorities in Energy Strategic Plan Executive Summary: September 24, 2013 Kick Off of the Minorities in Energy Initiative Program Booklet - November 13 2013

  12. Station Footprint: Separation Distances, Storage Options, and Pre-Cooling |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy Station Footprint: Separation Distances, Storage Options, and Pre-Cooling Station Footprint: Separation Distances, Storage Options, and Pre-Cooling This presentation by Aaron Harris of Sandia National Laboratories was given at the DOE Hydrogen Compression, Storage, and Dispensing Workshop in March 2013. PDF icon csd_workshop_12_harris.pdf More Documents & Publications Light Duty Fuel Cell Electric Vehicle Hydrogen Fueling Protocol H2FIRST Reference Station Design

  13. Federal Agencies Outline Bioeconomy Vision and Current Activities |

    Office of Environmental Management (EM)

    Department of Energy Agencies Outline Bioeconomy Vision and Current Activities Federal Agencies Outline Bioeconomy Vision and Current Activities February 22, 2016 - 12:30pm Addthis Federal Agencies Outline Bioeconomy Vision and Current Activities Harry Baumes Harry Baumes Senior Executive Advisor to the Bioenergy Technologies Office and Director, Office of Energy Policy and New Uses, U.S. Department of Agriculture This week at the Advanced Bioeconomy Leadership Conference, the U.S.

  14. MIE Webinar | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    MIE Webinar MIE Webinar Minorities in Energy Minorities in Energy Read more Secretary Moniz and Director Harris of Economic Impact and Diversity Secretary Moniz and Director Harris of Economic Impact and Diversity Read more Quadrennial Energy Review Quadrennial Energy Review Read more National Climate Assesment National Climate Assesment Read more Regional Climate Change Webinar Presentation Regional Climate Change Webinar Presentation Read more Background In September 2013, the Department of

  15. ~tx22C0.ptx

    Broader source: Energy.gov (indexed) [DOE]

    + + + + + STUDYING THE COMMUNICATIONS REQUIREMENTS OF ELECTRIC UTILITIES TO INFORM FEDERAL SMART GRID POLICIES + + + + + PUBLIC MEETING + + + + + THURSDAY, JUNE 17, 2010 + + + + + The Public Meeting was held in Room 8E069 at the Department of Energy, Forrestal Building, 1000 Independence Avenue, S.W., Washington, D.C., at 10:00 a.m., Scott Blake Harris, Chair, presiding. PRESENT: BECKY BLALOCK SHERMAN J. ELLIOTT LYNNE ELLYN SCOTT BLAKE HARRIS JIM INGRAHAM JIM L. JONES MICHAEL LANMAN KYLE

  16. Title Preliminary Assessment of Geothermal Potential Author

    National Nuclear Security Administration (NNSA)

    Preliminary Assessment of Geothermal Potential Author Harry Reid Center / PAI 101443 Document Date ERC Index number 12/30/94 05.09.487 Document Type Box Number Report 1667-1 Recipients DOE DE-FC08-93NV11399 NTSEIS ADMINISTRATIVE RECORD PRELIMINARY ASSESSMENT OF GEOTHERMAL POTENTIAL NEVADA TEST SITE j NYE COUNTY, NEVADA Prepared for: UNITED STATES DEPARTMENT OF ENERGY Prepared by: DIVISION OF EARTH SCIENCES HARRY REID CENTER FOR ENVIRONMENTAL STUDIES UNIVERSITY OF NEVADA, LAS VEGAS LAS VEGAS,

  17. Grazing-incidence small-angle X-ray scattering: application to the study of quantum dot lattices

    SciTech Connect (OSTI)

    Buljan, Maja Radi?, Nikola; Bernstorff, Sigrid; Drai?, Goran; Bogdanovi?-Radovi?, Iva; Hol, Vclav

    2012-01-01

    The modelling of grazing-incidence small-angle X-ray scattering (GISAXS) from three-dimensional quantum dot lattices is described. The ordering of quantum dots in three-dimensional quantum dot lattices is investigated by grazing-incidence small-angle X-ray scattering (GISAXS). Theoretical models describing GISAXS intensity distributions for three general classes of lattices of quantum dots are proposed. The classes differ in the type of disorder of the positions of the quantum dots. The models enable full structure determination, including lattice type, lattice parameters, the type and degree of disorder in the quantum dot positions and the distributions of the quantum dot sizes. Applications of the developed models are demonstrated using experimentally measured data from several types of quantum dot lattices formed by a self-assembly process.

  18. Statistical theory of Coulomb blockade oscillations: Quantum chaos in quantum dots

    SciTech Connect (OSTI)

    Jalabert, R.A.; Stone, A.D.; Alhassid, Y. (Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, Connecticut 06511 (United States))

    1992-06-08

    We develop a statistical theory of the amplitude of Coulomb blockade oscillations in semiconductor quantum dots based on the hypothesis that chaotic dynamics in the dot potential leads to behavior described by random-matrix theory. Breaking time-reversal symmetry is predicted to cause an experimentally observable change in the distribution of amplitudes. The theory is tested numerically and good agreement is found.

  19. Prediction of a strain-induced conduction-band minimum in embedded quantum dots

    SciTech Connect (OSTI)

    Williamson, A.J.; Zunger, A.; Canning, A.

    1998-02-01

    Free-standing InP quantum dots have previously been theoretically and experimentally shown to have a direct band gap across a large range of experimentally accessible sizes. We demonstrated that when these dots are embedded coherently within a GaP barrier material, the effects of quantum confinement in conjunction with coherent strain suggest there will be a critical diameter of dot ({approx}60 {Angstrom}), above which the dot is direct, type I, and below which it is indirect, type II. However, the strain in the system acts to produce another conduction state with an even lower energy, in which electrons are localized in small pockets at the interface between the InP dot and the GaP barrier. Since this conduction state is GaP X{sub 1c} derived and the highest occupied valence state is InP, {Gamma} derived, the fundamental transition is predicted to be indirect in both real and reciprocal space ({open_quotes}type II{close_quotes}) for all dot sizes. This effect is peculiar to the strained dot, and is absent in the freestanding dot. {copyright} {ital 1998} {ital The American Physical Society}

  20. Probing the size and environment induced phase transformation in CdSe quantum dots

    SciTech Connect (OSTI)

    Karakoti, Ajay S.; Sanghavi, Shail P.; Nachimuthu, Ponnusamy; Yang, Ping; Thevuthasan, Suntharampillai

    2011-11-17

    The structural and electronic properties of CdSe quantum dots in toluene and drop-casted on Si wafer were investigated by in-situ micro X-ray diffraction, X-ray photoelectron spectroscopy and UV-Vis absorption and emission spectroscopy. The in-situ micro diffraction data show that the CdSe quantum dots capped with TOPO or hexadecylamine (HDA) in toluene exhibit predominantly wurtzite crystal structure, which undergoes a phase transformation to zinc blende crystal structure following drop casting on Si and this phase transition increases with decreasing the size of the CdSe quantum dots. Decreasing the size of quantum dots also increases the Se vacancies that facilitate the phase transformation. The X-ray photoelectron spectra show a systematic increase in the core level binding energies of Cd 3d and Se 3d, the band gap and the Cd/Se ratio as the size of the quantum dots decreases from 6.6nm to 2.1nm. This is attributed to the quantum confinement of CdSe crystallites by the capping ligands in toluene which increases with decreasing the size of the quantum dots. However, drop-casting quantum dots on Si alter the density and arrangement of capping ligands and solvent molecules on the quantum dots which causes significant phase transformation.

  1. Photocurrent extraction efficiency in colloidal quantum dot photovoltaics

    SciTech Connect (OSTI)

    Kemp, K. W.; Wong, C. T. O.; Hoogland, S. H.; Sargent, E. H.

    2013-11-18

    The efficiency of photocurrent extraction was studied directly inside operating Colloidal Quantum Dot (CQD) photovoltaic devices. A model was derived from first principles for a thin film p-n junction with a linearly spatially dependent electric field. Using this model, we were able to clarify the origins of recent improvement in CQD solar cell performance. From current-voltage diode characteristics under 1 sun conditions, we extracted transport lengths ranging from 39 nm to 86 nm for these materials. Characterization of the intensity dependence of photocurrent extraction revealed that the dominant loss mechanism limiting the transport length is trap-mediated recombination.

  2. Activation of molecular catalysts using semiconductor quantum dots

    DOE Patents [OSTI]

    Meyer, Thomas J. (Chapel Hill, NC); Sykora, Milan (Los Alamos, NM); Klimov, Victor I. (Los Alamos, NM)

    2011-10-04

    Photocatalytic materials based on coupling of semiconductor nanocrystalline quantum dots (NQD) and molecular catalysts. These materials have capability to drive or catalyze non-spontaneous chemical reactions in the presence of visible radiation, ultraviolet radiation, or both. The NQD functions in these materials as a light absorber and charge generator. Following light absorption, the NQD activates a molecular catalyst adsorbed on the surface of the NQD via transfer of one or more charges (either electrons or electron-holes) from the NQD to the molecular catalyst. The activated molecular catalyst can then drive a chemical reaction. A photoelectrolytic device that includes such photocatalytic materials is also described.

  3. Electronic structure of nanocrystal quantum-dot quantumwells

    SciTech Connect (OSTI)

    Schrier, Joshua; Wang, Lin-Wang

    2006-06-26

    The electronic states of CdS/CdSe/CdS colloidal nanocrystalquantum-dot quantum wells are studied by large-scale pseudopotentiallocal density approximation (LDA) calculations. Using this approach, wedetermine the effects of CdS core size, CdSe well thickness, and CdSshell thickness on the band-edge wave functions, band-gap, andelectron-hole Coulomb interactions. We find the conduction-band wavefunction to be less confined to the CdSe well layer than predicted by kcdot p effective-mass theory, which accounts for the previous underestimation of the electron g factor.

  4. Photoluminescence-enhanced biocompatible quantum dots by phospholipid functionalization

    SciTech Connect (OSTI)

    Shi Yunfeng; He Peng Zhu Xinyuan

    2008-10-02

    A simple two-step strategy using phospholipid (PPL) to functionalize core/shell CdSe/ZnS quantum dots (QDs) has been described. The experimental data show that the use of S-H terminated PPL results not only in the high colloidal stability of core/shell CdSe/ZnS QDs in the aqueous phase, but also in the significant enhancement of photoluminescence. The degree of the enhancement is a function of the PPL-CdSe/ZnS QDs sample concentration. These results might be promising for future biological platform in new devices ranging from photovoltaic cells to biosensors and other devices.

  5. Ratiometric Sensing of Toxins using Quantum Dots | Argonne National

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laboratory Ratiometric Sensing of Toxins using Quantum Dots December 4, 2015 Tweet EmailPrint Botulinum neurotoxin (BoNT) presents a significant hazard under numerous realistic scenarios. BoNT is the most toxic substance known. Current tests for BoNT are slow (2 days), lab-based, and complex. A new scheme offers quick, specific quantification by non-specialized personnel such as first responders in the field. The standard detection scheme for this fast-acting toxin is a lab-based mouse

  6. The dosimetric consequences of the new DOT LSA definition

    SciTech Connect (OSTI)

    Mis, F.J.

    1996-10-01

    As a result of the new regulations for the transportation of radioactive materials, the DOT and the NRC have implemented a rule designed to limit the activity in an LSA container. This is a new regulation designed to insure that the spirit of the law as well as the letter of the law are followed for LSA shipments. Specifically, it limits the dose rate at any location on an unshielded LSA container to less than 1 rem/hr at 3 meters. Other possible alternatives had been discussed prior to the implementation of this regulation including multiples of A{sub 2} values, as implemented by the French.

  7. Computational modeling of electrophotonics nanomaterials: Tunneling in double quantum dots

    SciTech Connect (OSTI)

    Vlahovic, Branislav Filikhin, Igor

    2014-10-06

    Single electron localization and tunneling in double quantum dots (DQD) and rings (DQR) and in particular the localized-delocalized states and their spectral distributions are considered in dependence on the geometry of the DQDs (DQRs). The effect of violation of symmetry of DQDs geometry on the tunneling is studied in details. The cases of regular and chaotic geometries are considered. It will be shown that a small violation of symmetry drastically affects localization of electron and that anti-crossing of the levels is the mechanism of tunneling between the localized and delocalized states in DQRs.

  8. Water-soluble luminescent quantum dots and biomolecular conjugates thereof and related compositions and method of use

    DOE Patents [OSTI]

    Nie, Shuming (Bloomington, IN); Chan, Warren C. W. (Bloomington, IN); Emory, Steven R. (Los Alamos, NM)

    2002-01-01

    The present invention provides a water-soluble luminescent quantum dot, a biomolecular conjugate thereof and a composition comprising such a quantum dot or conjugate. Additionally, the present invention provides a method of obtaining a luminescent quantum dot, a method of making a biomolecular conjugate thereof, and methods of using a biomolecular conjugate for ultrasensitive nonisotopic detection in vitro and in vivo.

  9. Water-soluble luminescent quantum dots and biomolecular conjugates thereof and related compositions and methods of use

    DOE Patents [OSTI]

    Nie, Shuming; Chan, Warren C. W.; Emory, Stephen

    2007-03-20

    The present invention provides a water-soluble luminescent quantum dot, a biomolecular conjugate thereof and a composition comprising such a quantum dot or conjugate. Additionally, the present invention provides a method of obtaining a luminescent quantum dot, a method of making a biomolecular conjugate thereof, and methods of using a biomolecular conjugate for ultrasensitive nonisotopic detection in vitro and in vivo.

  10. Intermediate-band photosensitive device with quantum dots embedded in energy fence barrier

    DOE Patents [OSTI]

    Forrest, Stephen R. (Ann Arbor, MI); Wei, Guodan (Ann Arbor, MI)

    2010-07-06

    A plurality of layers of a first semiconductor material and a plurality of dots-in-a-fence barriers disposed in a stack between a first electrode and a second electrode. Each dots-in-a-fence barrier consists essentially of a plurality of quantum dots of a second semiconductor material embedded between and in direct contact with two layers of a third semiconductor material. Wave functions of the quantum dots overlap as at least one intermediate band. The layers of the third semiconductor material are arranged as tunneling barriers to require a first electron and/or a first hole in a layer of the first material to perform quantum mechanical tunneling to reach the second material within a respective quantum dot, and to require a second electron and/or a second hole in a layer of the first semiconductor material to perform quantum mechanical tunneling to reach another layer of the first semiconductor material.

  11. Charge-transfer dynamics in multilayered PbS and PbSe quantum dot architectures

    SciTech Connect (OSTI)

    Xu, F.; Ma, X.; Haughn, C. R.; Doty, M. F.; Cloutier, S. G.

    2014-02-03

    We demonstrate control of the charge transfer process in PbS and PbSe quantum dot assemblies. We first demonstrate efficient charge transfer from donor quantum dots to acceptor quantum dots in a multi-layer PbSe cascade structure. Then, we assemble type-I and type-II heterostructures using both PbS and PbSe quantum dots via careful control of the band alignment. In type-I structures, photo-generated carriers are transferred and localized in the smaller bandgap (acceptor) quantum dots, resulting in a significant luminescence enhancement. In contrast, a significant luminescence quenching and shorter emission lifetime confirms an efficient separation of photo-generated carriers in the type-II architecture.

  12. Induced spin-accumulation and spin-polarization in a quantum-dot ring by using magnetic quantum dots and Rashba spin-orbit effect

    SciTech Connect (OSTI)

    Eslami, L., E-mail: Leslami@iust.ac.ir; Faizabadi, E. [School of Physics, Iran University of Science and Technology, Tehran 16846 (Iran, Islamic Republic of)

    2014-05-28

    The effect of magnetic contacts on spin-dependent electron transport and spin-accumulation in a quantum ring, which is threaded by a magnetic flux, is studied. The quantum ring is made up of four quantum dots, where two of them possess magnetic structure and other ones are subjected to the Rashba spin-orbit coupling. The magnetic quantum dots, referred to as magnetic quantum contacts, are connected to two external leads. Two different configurations of magnetic moments of the quantum contacts are considered; the parallel and the anti-parallel ones. When the magnetic moments are parallel, the degeneracy between the transmission coefficients of spin-up and spin-down electrons is lifted and the system can be adjusted to operate as a spin-filter. In addition, the accumulation of spin-up and spin-down electrons in non-magnetic quantum dots are different in the case of parallel magnetic moments. When the intra-dot Coulomb interaction is taken into account, we find that the electron interactions participate in separation between the accumulations of electrons with different spin directions in non-magnetic quantum dots. Furthermore, the spin-accumulation in non-magnetic quantum dots can be tuned in the both parallel and anti-parallel magnetic moments by adjusting the Rashba spin-orbit strength and the magnetic flux. Thus, the quantum ring with magnetic quantum contacts could be utilized to create tunable local magnetic moments which can be used in designing optimized nanodevices.

  13. Colloidal quantum dot solar cells on curved and flexible substrates

    SciTech Connect (OSTI)

    Kramer, Illan J.; Moreno-Bautista, Gabriel; Minor, James C.; Kopilovic, Damir; Sargent, Edward H.

    2014-10-20

    Colloidal quantum dots (CQDs) are semiconductor nanocrystals synthesized with, processed in, and deposited from the solution phase, potentially enabling low-cost, facile manufacture of solar cells. Unfortunately, CQD solar cell reports, until now, have only explored batch-processing methodssuch as spin-coatingthat offer limited capacity for scaling. Spray-coating could offer a means of producing uniform colloidal quantum dot films that yield high-quality devices. Here, we explore the versatility of the spray-coating method by producing CQD solar cells in a variety of previously unexplored substrate arrangements. The potential transferability of the spray-coating method to a roll-to-roll manufacturing process was tested by spray-coating the CQD active layer onto six substrates mounted on a rapidly rotating drum, yielding devices with an average power conversion efficiency of 6.7%. We further tested the manufacturability of the process by endeavoring to spray onto flexible substrates, only to find that spraying while the substrate was flexed was crucial to achieving champion performance of 7.2% without compromise to open-circuit voltage. Having deposited onto a substrate with one axis of curvature, we then built our CQD solar cells onto a spherical lens substrate having two axes of curvature resulting in a 5% efficient device. These results show that CQDs deposited using our spraying method can be integrated to large-area manufacturing processes and can be used to make solar cells on unconventional shapes.

  14. Effect of swift heavy ion irradiation on bare and coated ZnS quantum dots

    SciTech Connect (OSTI)

    Chowdhury, S. Hussain, A.M.P.; Ahmed, G.A.; Singh, F.; Avasthi, D.K.; Choudhury, A.

    2008-12-01

    The present study compares structural and optical modifications of bare and silica (SiO{sub 2}) coated ZnS quantum dots under swift heavy ion (SHI) irradiation. Bare and silica coated ZnS quantum dots were prepared following an inexpensive chemical route using polyvinyl alcohol (PVA) as the dielectric host matrix. X-ray diffraction (XRD) and transmission electron microscopy (TEM) study of the samples show the formation of almost spherical ZnS quantum dots. The UV-Vis absorption spectra reveal blue shift relative to bulk material in absorption energy while photoluminescence (PL) spectra suggests that surface state and near band edge emissions are dominating in case of bare and coated samples, respectively. Swift heavy ion irradiation of the samples was carried out with 160 MeV Ni{sup 12+} ion beam with fluences 10{sup 12} to 10{sup 13} ions/cm{sup 2}. Size enhancement of bare quantum dots after irradiation has been indicated in XRD and TEM analysis of the samples which has also been supported by optical absorption spectra. However similar investigations on irradiated coated quantum dots revealed little change in quantum dot size and emission. The present study thus shows that the coated ZnS quantum dots are stable upon SHI irradiation compared to the bare one.

  15. Tuning the properties of Ge-quantum dots superlattices in amorphous silica matrix through deposition conditions

    SciTech Connect (OSTI)

    Pinto, S. R. C.; Ramos, M. M. D.; Gomes, M. J. M.; Buljan, M.; Chahboun, A.; Roldan, M. A.; Molina, S. I.; Bernstorff, S.; Varela, M.; Pennycook, S. J.; Barradas, N. P.; Alves, E.

    2012-04-01

    In this work, we investigate the structural properties of Ge quantum dot lattices in amorphous silica matrix, prepared by low-temperature magnetron sputtering deposition of (Ge+SiO{sub 2})/SiO{sub 2} multilayers. The dependence of quantum dot shape, size, separation, and arrangement type on the Ge-rich (Ge + SiO{sub 2}) layer thickness is studied. We show that the quantum dots are elongated along the growth direction, perpendicular to the multilayer surface. The size of the quantum dots and their separation along the growth direction can be tuned by changing the Ge-rich layer thickness. The average value of the quantum dots size along the lateral (in-plane) direction along with their lateral separation is not affected by the thickness of the Ge-rich layer. However, the thickness of the Ge-rich layer significantly affects the quantum dot ordering. In addition, we investigate the dependence of the multilayer average atomic composition and also the quantum dot crystalline quality on the deposition parameters.

  16. Far off-resonant coupling between photonic crystal microcavity and single quantum dot with resonant excitation

    SciTech Connect (OSTI)

    Banihashemi, Mehdi; Ahmadi, Vahid, E-mail: v-ahmadi@modares.ac.ir [Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, P.O. Box 14115-194 (Iran, Islamic Republic of)] [Department of Electrical and Computer Engineering, Tarbiat Modares University, Tehran, P.O. Box 14115-194 (Iran, Islamic Republic of); Nakamura, Tatsuya; Kojima, Takanori; Kojima, Kazunobu; Noda, Susumu [Department of Electronic Science and Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)] [Department of Electronic Science and Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2013-12-16

    In this paper, we experimentally demonstrate that with sub-nanowatt coherent s-shell excitation of a single InAs quantum dot, off-resonant coupling of 4.1?nm is possible between L3 photonic crystal microcavity and the quantum dot at 50?K. This resonant excitation reduces strongly the effect of surrounding charges to quantum dot, multiexciton complexes and pure dephasing. It seems that this far off-resonant coupling is the result of increased number of acoustical phonons due to high operating temperature of 50?K. The 4.1?nm detuning is the largest amount for this kind of coupling.

  17. Direct Observation of Energy-Gap Scaling Law in CdSe Quantum Dots with Positrons

    SciTech Connect (OSTI)

    Denison, Arthur Blanchard; Weber, M. H.; Lynn, K. G.; Barbiellini, B.; Sterne, P. A.

    2002-07-01

    CdSe quantum dot samples with sizes in the range of 1.8~6 nm in diameter were examined by positron annihilation spectroscopy. The results were compared to data obtained for single-crystal bulk CdSe. Evidence is provided that the positrons annihilate within the nanospheres. The annihilation line shape shows a smearing at the boundary of the Jones zone proportional to the widening of the band gap due to a reduction in the size of the quantum dots. The data confirm that the change in the band gap is inversely proportional to the square of the quantum dot diameter.

  18. The use of bulk states to accelerate the band edge statecalculation of a semiconductor quantum dot

    SciTech Connect (OSTI)

    Vomel, Christof; Tomov, Stanimire Z.; Wang, Lin-Wang; Marques,Osni A.; Dongarra, Jack J.

    2006-05-10

    We present a new technique to accelerate the convergence of the folded spectrum method in empirical pseudopotential band edge state calculations for colloidal quantum dots. We use bulk band states of the materials constituent of the quantum dot to construct initial vectors and a preconditioner. We apply these to accelerate the convergence of the folded spectrum method for the interior states at the top of the valence and the bottom of the conduction band. For large CdSe quantum dots, the number of iteration steps until convergence decreases by about a factor of 4 compared to previous calculations.

  19. R&D Magazine: Windows into Solar Power Sources with Quantum Dots

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    R&D Magazine: Windows into Solar Power Sources with Quantum Dots August 30, 2015 R&D Magazine: Windows into Solar Power Sources with Quantum Dots A luminescent solar concentrator is an emerging sunlight harvesting technology that has the potential to disrupt the way we think about energy: It could turn any window into a daytime power source. "In these devices, a fraction of light transmitted through the window is absorbed by nano-sized particles (semiconductor quantum dots)

  20. Enhanced single photon emission from positioned InP/GaInP quantum dots

    Office of Scientific and Technical Information (OSTI)

    coupled to a confined Tamm-plasmon mode (Journal Article) | SciTech Connect Enhanced single photon emission from positioned InP/GaInP quantum dots coupled to a confined Tamm-plasmon mode Citation Details In-Document Search Title: Enhanced single photon emission from positioned InP/GaInP quantum dots coupled to a confined Tamm-plasmon mode We report on the enhancement of the spontaneous emission in the visible red spectral range from site-controlled InP/GaInP quantum dots by resonant coupling

  1. Red light-emitting diodes based on InP/GaP quantum dots

    SciTech Connect (OSTI)

    Hatami, F.; Lordi, V.; Harris, J.S.; Kostial, H.; Masselink, W.T.

    2005-05-01

    The growth, fabrication, and device characterization of InP quantum-dot light-emitting diodes based on GaP are described and discussed. The diode structures are grown on gallium phosphide substrates using gas-source molecular-beam epitaxy and the active region of the diode consists of self-assembled InP quantum dots embedded in a GaP matrix. Red electroluminescence originating from direct band-gap emission from the InP quantum dots is observed at low temperatures.With increasing temperature, however, the emission line shifts to the longer wavelength. The emission light is measured to above room temperature.

  2. R&D Magazine: Windows into Solar Power Sources with Quantum Dots

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    R&D Magazine: Windows into Solar Power Sources with Quantum Dots R&D Magazine: Windows into Solar Power Sources with Quantum Dots A luminescent solar concentrator is an emerging sunlight harvesting technology that has the potential to disrupt the way we think about energy: It could turn any window into a daytime power source. August 30, 2015 R&D Magazine: Windows into Solar Power Sources with Quantum Dots A luminescent solar concentrator is an emerging sunlight harvesting technology

  3. Synthesis of Non-blinking Semiconductor Quantum Dots Emitting in the

    Office of Scientific and Technical Information (OSTI)

    Near-Infrared (Conference) | SciTech Connect Synthesis of Non-blinking Semiconductor Quantum Dots Emitting in the Near-Infrared Citation Details In-Document Search Title: Synthesis of Non-blinking Semiconductor Quantum Dots Emitting in the Near-Infrared Our previous work demonstrates that Quasi-Type II CdSe/CdS core-shell quantum dots with thick shells (3-5 nm) exhibit unique photophysical characteristics, including improved chemical robustness over typical thin-shelled core/shell systems

  4. On-chip generation and guiding of quantum light from a site-controlled quantum dot

    SciTech Connect (OSTI)

    Jamil, Ayesha; Farrer, Ian; Griffiths, Jonathan P.; Jones, Geb A. C.; Ritchie, David A.; Skiba-Szymanska, Joanna; Kalliakos, Sokratis; Ward, Martin B.; Ellis, David J. P.; Shields, Andrew J.; Schwagmann, Andre; Brody, Yarden; Cambridge Research Laboratory, Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ

    2014-03-10

    We demonstrate the emission and routing of single photons along a semiconductor chip originating from carrier recombination in an actively positioned InAs quantum dot. Devicescale arrays of quantum dots are formed by a twostep regrowth process. We precisely locate the propagating region of a unidirectional photonic crystal waveguide with respect to the quantum dot nucleation site. Under pulsed optical excitation, the multiphoton emission probability from the waveguide's exit is 12%??5% before any background correction. Our results are a major step towards the deterministic integration of a quantum emitter with the waveguiding components of photonic quantum circuits.

  5. Interaction of graphene quantum dots with bulk semiconductor surfaces

    SciTech Connect (OSTI)

    Mohapatra, P. K.; Singh, B. P.; Kushavah, Dushyant; Mohapatra, J.

    2015-05-15

    Highly luminescent graphene quantum dots (GQDs) are synthesized through thermolysis of glucose. The average lateral size of the synthesized GQDs is found to be ?5 nm. The occurrence of D and G band at 1345 and 1580 cm{sup ?1} in Raman spectrum confirms the presence of graphene layers. GQDs are mostly consisting of 3 to 4 graphene layers as confirmed from the AFM measurements. Photoluminescence (PL) measurement shows a distinct broadening of the spectrum when GQDs are on the semiconducting bulk surface compared to GQDs in water. The time resolved PL measurement shows a significant shortening in PL lifetime due to the substrate interaction on GQDs compared to the GQDs in solution phase.

  6. Location deterministic biosensing from quantum-dot-nanowire assemblies

    SciTech Connect (OSTI)

    Liu, Chao [Materials Science and Engineering Program, Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712 (United States); Kim, Kwanoh [Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Fan, D. L., E-mail: dfan@austin.utexas.edu [Materials Science and Engineering Program, Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712 (United States); Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States)

    2014-08-25

    Semiconductor quantum dots (QDs) with high fluorescent brightness, stability, and tunable sizes, have received considerable interest for imaging, sensing, and delivery of biomolecules. In this research, we demonstrate location deterministic biochemical detection from arrays of QD-nanowire hybrid assemblies. QDs with diameters less than 10?nm are manipulated and precisely positioned on the tips of the assembled Gold (Au) nanowires. The manipulation mechanisms are quantitatively understood as the synergetic effects of dielectrophoretic (DEP) and alternating current electroosmosis (ACEO) due to AC electric fields. The QD-nanowire hybrid sensors operate uniquely by concentrating bioanalytes to QDs on the tips of nanowires before detection, offering much enhanced efficiency and sensitivity, in addition to the position-predictable rationality. This research could result in advances in QD-based biomedical detection and inspires an innovative approach for fabricating various QD-based nanodevices.

  7. Quantum Dot Solar Cells with Multiple Exciton Generation

    SciTech Connect (OSTI)

    Hanna, M. C.; Beard, M. C.; Johnson, J. C.; Murphy, J.; Ellingson, R. J.; Nozik, A. J.

    2005-11-01

    We have measured the quantum yield of the multiple exciton generation (MEG) process in quantum dots (QDs) of the lead-salt semiconductor family (PbSe, PbTe, and PbS) using fs pump-probe transient absorption measurements. Very high quantum yields (up to 300%) for charge carrier generation from MEG have been measured in all of the Pb-VI QDs. We have calculated the potential maximum performance of various MEG QD solar cells in the detailed balance limit. We examined a two-cell tandem PV device with singlet fission (SF), QD, and normal dye (N) absorbers in the nine possible series-connected combinations to compare the tandem combinations and identify the combinations with the highest theoretical efficiency. We also calculated the maximum efficiency of an idealized single-gap MEG QD solar cell with M multiplications and its performance under solar concentration.

  8. TxDOT - Right of Way Forms webpage | Open Energy Information

    Open Energy Info (EERE)

    Right of Way Forms webpage Jump to: navigation, search OpenEI Reference LibraryAdd to library Web Site: TxDOT - Right of Way Forms webpage Abstract This webpage provides the...

  9. Exciton dissociation and interdot transport in CdSe quantum-dot molecules

    SciTech Connect (OSTI)

    Franceschetti, Alberto; Zunger, Alex

    2001-04-15

    One of the most important parameters that determine the transport properties of a quantum dot array is the exciton dissociation energy, i.e., the energy {Delta}E required to dissociate an exciton into an electron and a hole localized in different dots. We show that a pseudopotential calculation for a dot molecule, coupled with a basic configuration interaction calculation of the exciton energy levels, provides directly the exciton dissociation energy, including the effects of wave function overlap, screened Coulomb attraction between the electron and the hole in different dots, and polarization effects. We find that {Delta}E decreases as the interdot distance decreases and as the dielectric constant of the medium increases.

  10. Mechanism of lateral ordering of InP dots grown on InGaP layers

    SciTech Connect (OSTI)

    Bortoleto, J.R.R.; Gutierrez, H.R.; Cotta, M.A.; Bettini, J.

    2005-07-04

    The mechanisms leading to the spontaneous formation of a two-dimensional array of InP/InGaP dots grown by chemical-beam epitaxy are discussed. Samples where the InGaP buffer layer was grown at different conditions were characterized by transmission electron microscopy. Our results indicate that a periodic strain field related to lateral two-dimensional compositional modulation in the InGaP buffer layer determines the dot nucleation positions during InP growth. Although the periodic strain field in the InGaP is large enough to align the InP dots, both their shape and optical properties are effectively unaltered. This result shows that compositional modulation can be used as a tool for in situ dot positioning.

  11. Quantum Dots Promise to Significantly Boost Solar Cell Efficiencies (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2013-08-01

    In the search for a third generation of solar-cell technologies, a leading candidate is the use of 'quantum dots' -- tiny spheres of semiconductor material measuring only about 2-10 billionths of a meter in diameter. Quantum dots have the potential to dramatically increase the efficiency of converting sunlight into energy -- perhaps even doubling it in some devices -- because of their ability to generate more than one bound electron-hole pair, or exciton, per incoming photon. NREL has produced quantum dots using colloidal suspensions; then, using molecular self-assembly, they have been fabricated into the first-ever quantum-dot solar cells. While these devices operate with only 4.4% efficiency, they demonstrate the capability for low-cost manufacturing.

  12. Theoretical study of intraband optical transitions in conduction band of dot-in-a-well system

    SciTech Connect (OSTI)

    Chaganti, Venkata R.; Apalkov, Vadym

    2014-02-15

    We study numerically absorption optical spectra of n-doped InAs/In{sub 015}Ga{sub 085}As/GaAs quantum dot-in-a-well systems. The absorption spectra are mainly determined by the size of a quantum dot and have weak dependence on the thickness of quantum well and position of the dot in a well. The dot-in-a-well system is sensitive to both in-plane and out-of-plane polarizations of the incident light with much stronger absorption intensities for the in-plane-polarized light. The absorption spectrum of in-plane-polarized light has also a multi-peak structure with two or three peaks of comparable intensities, while the absorption spectrum of out-of-plane polarized light has a single well-pronounced peak.

  13. Mastermind Session: Connecting the Dots Between the Real Estate Market and Residential Energy Efficiency

    Broader source: Energy.gov [DOE]

    Better Buildings Residential Network Program Sustainability Series Mastermind Call: Connecting the Dots Between the Real Estate Market and Residential Energy Efficiency Featuring Host Rich Dooley, Arlington County, VA, Call Slides and Discussion Summary, August 14, 2014.

  14. InP quantum dots: Electronic structure, surface effects, and the redshifted emission

    SciTech Connect (OSTI)

    Fu, H.; Zunger, A.

    1997-07-01

    We present pseudopotential plane-wave electronic-structure calculations on InP quantum dots in an effort to understand quantum confinement and surface effects and to identify the origin of the long-lived and redshifted luminescence. We find that (i) unlike the case in small GaAs dots, the lowest unoccupied state of InP dots is the {Gamma}{sub 1c}-derived direct state rather than the X{sub 1c}-derived indirect state and (ii) unlike the prediction of {bold k}{center_dot}{bold p} models, the highest occupied state in InP dots has a 1sd-type envelope function rather than a (dipole-forbidden) 1pf envelope function. Thus explanations (i) and (ii) to the long-lived redshifted emission in terms of an orbitally forbidden character can be excluded. Furthermore, (iii) fully passivated InP dots have no surface states in the gap. However, (iv) removal of the anion-site passivation leads to a P dangling bond (DB) state just above the valence band, which will act as a trap for photogenerated holes. Similarly, (v) removal of the cation-site passivation leads to an In dangling-bond state below the conduction band. While the energy of the In DB state depends only weakly on quantum size, its radiative lifetime increases with quantum size. The calculated {approximately}300-meV redshift and the {approximately}18 times longer radiative lifetime relative to the dot-interior transition for the 26-{Angstrom} dot with an In DB are in good agreement with the observations of full-luminescence experiments for unetched InP dots. Yet, (vi) this type of redshift due to surface defect is inconsistent with that measured in {ital selective} excitation for HF-etched InP dots. (vii) The latter type of ({open_quotes}resonant{close_quotes}) redshift is compatible with the calculated {ital screened} singlet-triplet splitting in InP dots, suggesting that the slow emitting state seen in selective excitation could be a triplet state. {copyright} {ital 1997} {ital The American Physical Society}

  15. The effect of Coulomb interactions on thermoelectric properties of quantum dots

    SciTech Connect (OSTI)

    Zimbovskaya, Natalya A.

    2014-03-14

    Thermoelectric effects in a quantum dot coupled to the source and drain charge reservoirs are explored using a nonequilibrium Green's functions formalism beyond the Hartree-Fock approximation. Thermal transport is analyzed within a linear response regime. A transition from Coulomb blockade regime to Kondo regime in thermoelectric transport through a single-level quantum dot is traced using unified approximations for the relevant Green's functions.

  16. Final Progress Report for Project Entitled: Quantum Dot Tracers for Use in Engineered Geothermal Systems

    SciTech Connect (OSTI)

    Rose, Peter; Bartl, Michael; Reimus, Paul; Williams, Mark; Mella, Mike

    2015-09-12

    The objective of this project was to develop and demonstrate a new class of tracers that offer great promise for use in characterizing fracture networks in EGS reservoirs. From laboratory synthesis and testing through numerical modeling and field demonstrations, we have demonstrated the amazing versatility and applicability of quantum dot tracers. This report summarizes the results of four years of research into the design, synthesis, and characterization of semiconductor nanocrystals (quantum dots) for use as geothermal tracers.

  17. Quantum DotBridgeFullerene Heterodimers with Controlled Photoinduced Electron Transfer

    SciTech Connect (OSTI)

    Cotlet, M.; Xu, Z.

    2011-06-27

    A series of donor-bridge-acceptor systems in the form of core/shell CdSe/ZnS quantum dot-bridge-fullerene heterodimers (see picture) with varying bridge length and varying quantum dot size were self-assembled by a surface-based stepwise method to demonstrate control of the rate and of the magnitude of fluctuations of photoinduced electron transfer at the single-molecule level.

  18. Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Phosphor for LED based Solid State Lighting (Technical Report) | SciTech Connect Technical Report: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting Citation Details In-Document Search Title: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting Authors: Kundu, Janardan [1] ; Ghosh, Yagnaseni [1] ; Dennis, Allison M. [1] ; Htoon, Han [1] ; Hollingsworth, Jennifer A

  19. Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion

    Office of Scientific and Technical Information (OSTI)

    Phosphor for LED based Solid State Lighting (Technical Report) | SciTech Connect Technical Report: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting Citation Details In-Document Search Title: Giant Nanocrystal Quantum Dots as Stable and Efficient Down-Conversion Phosphor for LED based Solid State Lighting Authors: Kundu, Janardan [1] ; Ghosh, Yagnaseni [1] ; Dennis, Allison M. [1] ; Htoon, Han [1] ; Hollingsworth, Jennifer A

  20. Overview of DOE - DOT December 2009 CNG and Hydrogen Fuels Workshop |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy - DOT December 2009 CNG and Hydrogen Fuels Workshop Overview of DOE - DOT December 2009 CNG and Hydrogen Fuels Workshop These slides were presented at the Onboard Storage Tank Workshop on April 29, 2010. PDF icon overview_doedot_ostw.pdf More Documents & Publications Workshop Notes from ""Compressed Natural Gas and Hydrogen Fuels: Lessons Learned for the Safe Deployment of Vehicles"" Workshop, December 10-11, 2009 Safety and Regulatory Structure

  1. "Giant" nanocrystal quantum dots for light-emission applications

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect "Giant" nanocrystal quantum dots for light-emission applications Citation Details In-Document Search Title: "Giant" nanocrystal quantum dots for light-emission applications Authors: Hollingsworth, Jennifer A. [1] + Show Author Affiliations Los Alamos National Laboratory Publication Date: 2013-02-15 OSTI Identifier: 1063241 Report Number(s): LA-UR-13-21028 DOE Contract Number: AC52-06NA25396 Resource Type: Conference Resource Relation:

  2. Regulatory compliance guide for DOT-7A type A packaging design

    SciTech Connect (OSTI)

    Kelly, D.L.

    1996-06-04

    The purpose of this guide is to provide instruction for assuring that the regulatory design requirements for a DOT-7A Type A packaging are met. This guide also supports the testing and evaluation activities that are performed on new packaging designs by a DOE-approved test facility through the DOE`s DOT-7A Test Program. This Guide was updated to incorporate regulatory changes implemented by HM-169A (49 CFR, `Transportation`).

  3. SUNY/Buffalo Developing High-Efficiency Colloidal Quantum Dot Phosphors |

    Energy Savers [EERE]

    Department of Energy Research & Development » R&D Highlights » SUNY/Buffalo Developing High-Efficiency Colloidal Quantum Dot Phosphors SUNY/Buffalo Developing High-Efficiency Colloidal Quantum Dot Phosphors Photo of a synthesis flask containing newly formed nanocrystal emitters. The emitters show bright yellow luminescence. The State University of New York at Buffalo is working to reduce the cost and increase the performance of LEDs for general illumination by developing

  4. Approaches to Future Generation Photovoltaics and Solar Fuels: Multiple Exciton Generation in Quantum Dots, Quantum Dot Arrays, Molecular Singlet Fission, and Quantum Dot Solar Cells

    SciTech Connect (OSTI)

    Nozik, A. J.; Beard, M. C.; Johnson, J. C.; Hanna, M. C.; Luther, J. M.; Midgett, A.; Semonin, O.; Michel, J.

    2012-01-01

    One potential, long-term approach to more efficient future generation solar cells is to utilize the unique properties of quantum dots (QDs) and unique molecular chromophores to control the relaxation pathways of excited states to produce enhanced conversion efficiency through efficient multiple electron-hole pair generation from single photons . We have observed efficient multiple exciton generation (MEG) in PbSe, PbS, PbTe, and Si QDs and efficient singlet fission (SF) in molecules that satisfy specific requirements for their excited state energy level structure to achieve carrier multiplication. We have studied MEG in close-packed QD arrays where the QDs are electronically coupled in the films and thus exhibit good transport while still maintaining quantization and MEG. We have developed simple, all-inorganic QD solar cells that produce large short-circuit photocurrents and power conversion efficiencies in the 3-5% range via both nanocrystalline Schottky junctions and nanocrystalline p-n junctions. These solar cells also show QYs for photocurrent that exceed 100% in the photon energy regions where MEG is possible; the photocurrent MEG QYs as a function of photon energy match those determined via time-resolved spectroscopy. We have also observed very efficient SF in thin films of molecular crystals of 1,3 diphenylisobenzofuran with quantum yields of 200% at the optimum SF threshold of 2Eg (HOMO-LUMO for S{sub 0}-S{sub 1}), reflecting the creation of two excited triplet states from the first excited singlet state. Various possible configurations for novel solar cells based on MEG in QDs and SF in molecules that could produce high conversion efficiencies will be presented, along with progress in developing such new types of solar cells. Recent analyses of the effect of MEG or SF combined with solar concentration on the conversion efficiency of solar cells will be discussed.

  5. Characterization of the nanoDot OSLD dosimeter in CT

    SciTech Connect (OSTI)

    Scarboro, Sarah B.; Cody, Dianna; Followill, David; Court, Laurence; Stingo, Francesco C.; Kry, Stephen F.; Alvarez, Paola; Zhang, Di; McNitt-Gray, Michael

    2015-04-15

    Purpose: The extensive use of computed tomography (CT) in diagnostic procedures is accompanied by a growing need for more accurate and patient-specific dosimetry techniques. Optically stimulated luminescent dosimeters (OSLDs) offer a potential solution for patient-specific CT point-based surface dosimetry by measuring air kerma. The purpose of this work was to characterize the OSLD nanoDot for CT dosimetry, quantifying necessary correction factors, and evaluating the uncertainty of these factors. Methods: A characterization of the Landauer OSL nanoDot (Landauer, Inc., Greenwood, IL) was conducted using both measurements and theoretical approaches in a CT environment. The effects of signal depletion, signal fading, dose linearity, and angular dependence were characterized through direct measurement for CT energies (80140 kV) and delivered doses ranging from ?5 to >1000 mGy. Energy dependence as a function of scan parameters was evaluated using two independent approaches: direct measurement and a theoretical approach based on Burlin cavity theory and Monte Carlo simulated spectra. This beam-quality dependence was evaluated for a range of CT scanning parameters. Results: Correction factors for the dosimeter response in terms of signal fading, dose linearity, and angular dependence were found to be small for most measurement conditions (<3%). The relative uncertainty was determined for each factor and reported at the two-sigma level. Differences in irradiation geometry (rotational versus static) resulted in a difference in dosimeter signal of 3% on average. Beam quality varied with scan parameters and necessitated the largest correction factor, ranging from 0.80 to 1.15 relative to a calibration performed in air using a 120 kV beam. Good agreement was found between the theoretical and measurement approaches. Conclusions: Correction factors for the measurement of air kerma were generally small for CT dosimetry, although angular effects, and particularly effects due to changes in beam quality, could be more substantial. In particular, it would likely be necessary to account for variations in CT scan parameters and measurement location when performing CT dosimetry using OSLD.

  6. Cavity-enhanced single photon emission from site-controlled In(Ga)As quantum dots fabricated using nanoimprint lithography

    SciTech Connect (OSTI)

    Tommila, J.; Hakkarainen, T. V.; Schramm, A. Guina, M.; Belykh, V. V.; Sibeldin, N. N.; Heinonen, E.

    2014-05-26

    We report on the emission dynamics of single In(Ga)As quantum dots formed in etched GaAs pits and integrated into micropillar cavities. The site-controlled quantum dots were fabricated by molecular beam epitaxy on nanoimprint lithography patterned GaAs(001) surfaces. Triggered single photon emission confirmed by photon autocorrelation measurements is demonstrated. Time-resolved photoluminescence experiments clearly show an effect of the cavity on the spontaneous emission rate of the quantum dot.

  7. Ground state energy of an exciton in a spherical quantum dot in the presence of an external magnetic field

    SciTech Connect (OSTI)

    Jahan K, Luhluh Boda, Aalu; Chatterjee, Ashok

    2015-05-15

    The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the presence of an external magnetic field. A variational method is employed to obtain the ground state energy of the exciton as a function of the quantum dot size, the confinement strength and the magnetic field. It is also shown that the variation of the size of the exciton with the radius of the quantum dot.

  8. Electrically driven single photon emission from a CdSe/ZnSSe single quantum dot at 200?K

    SciTech Connect (OSTI)

    Quitsch, Wolf; Kmmell, Tilmar; Bacher, Gerd; Gust, Arne; Kruse, Carsten; Hommel, Detlef

    2014-09-01

    High temperature operation of an electrically driven single photon emitter based on a single epitaxial quantum dot is reported. CdSe/ZnSSe/MgS quantum dots are embedded into a p-i-n diode architecture providing almost background free excitonic and biexcitonic electroluminescence from individual quantum dots through apertures in the top contacts. Clear antibunching with g{sup 2}(??=?0)?=?0.28??0.20 can be tracked up to T?=?200?K, representing the highest temperature for electrically triggered single photon emission from a single quantum dot device.

  9. Quantum-Dots Based Electrochemical Immunoassay of Interleukin-1?

    SciTech Connect (OSTI)

    Wu, Hong; Liu, Guodong; Wang, Jun; Lin, Yuehe

    2007-07-01

    We describe a quantum-dot (QD, CdSe@ZnS)-based electrochemical immunoassay to detect a protein biomarker, interleukin-1? (IL-1?). QD conjugated with anti-IL-1? antibody was used as a label in an immunorecognition event. After a complete sandwich immunoreaction among the primary IL-1? antibody (immobilized on the avidin-modified magnetic beads), IL-1?, and the QD-labeled secondary antibody, QD labels were attached to the magnetic-bead surface through the antibody-antigen immunocomplex. Electrochemical stripping analysis of the captured QDs was used to quantify the concentration of IL-1? after an acid-dissolution step. The streptavidin-modified magnetic beads and the magnetic separation platform were used to integrate a facile antibody immobilization (through a biotin/streptavidin interaction) with immunoreactions and the isolation of immunocomplexes from reaction solutions in the assay. The voltammetric response is highly linear over the range of 0.5 to 50 ng mL-1 IL 1?, and the limit of detection is estimated to be 0.3 ng mL-1 (18 pM). This QD-based electrochemical immunoassay shows great promise for rapid, simple, and cost-effective analysis of protein biomarkers.

  10. Quantum Dot Solar Cells: High Efficiency through Multiple Exciton Generation

    SciTech Connect (OSTI)

    Hanna, M. C.; Ellingson, R. J.; Beard, M.; Yu, P.; Micic, O. I.; Nozik, A. J.; c.

    2005-01-01

    Impact ionization is a process in which absorbed photons in semiconductors that are at least twice the bandgap can produce multiple electron-hole pairs. For single-bandgap photovoltaic devices, this effect produces greatly enhanced theoretical thermodynamic conversion efficiencies that range from 45-85%, depending upon solar concentration, the cell temperature, and the number of electron-hole pairs produced per photon. For quantum dots (QDs), electron-hole pairs exist as excitons. We have observed astoundingly efficient multiple exciton generation (MEG) in QDs of PbSe (bulk Eg = 0.28 eV), ranging in diameter from 3.9 to 5.7nm (Eg = 0.73, 0.82, and 0.91 eV, respectively). The effective masses of electron and holes are about equal in PbSe, and the onset for efficient MEG occurs at about three times the QD HOMO-LUMO transition (its ''bandgap''). The quantum yield rises quickly after the onset and reaches 300% at 4 x Eg (3.64 eV) for the smallest QD; this means that every QD in the sample produces three electron-hole pairs/photon.

  11. PROPERTIES OF UMBRAL DOTS FROM STRAY LIGHT CORRECTED HINODE FILTERGRAMS

    SciTech Connect (OSTI)

    Louis, Rohan E.; Mathew, Shibu K.; Bayanna, A. Raja; Rubio, Luis R. Bellot; Ichimoto, Kiyoshi; Ravindra, B.

    2012-06-20

    High-resolution blue continuum filtergrams from Hinode are employed to study the umbral fine structure of a regular unipolar sunspot. The removal of scattered light from the images increases the rms contrast by a factor of 1.45 on average. Improvement in image contrast renders identification of short filamentary structures resembling penumbrae that are well separated from the umbra-penumbra boundary and comprise bright filaments/grains flanking dark filaments. Such fine structures were recently detected from ground-based telescopes and have now been observed with Hinode. A multi-level tracking algorithm was used to identify umbral dots (UDs) in both the uncorrected and corrected images and to track them in time. The distribution of the values describing the photometric and geometric properties of UDs is more easily affected by the presence of stray light while it is less severe in the case of kinematic properties. Statistically, UDs exhibit a peak intensity, effective diameter, lifetime, horizontal speed, and a trajectory length of 0.29I{sub QS}, 272 km, 8.4 minutes, 0.45 km s{sup -1}, and 221 km, respectively. The 2 hr 20 minute time sequence depicts several locations where UDs tend to appear and disappear repeatedly with various time intervals. The correction for scattered light in the Hinode filtergrams facilitates photometry of umbral fine structure, which can be related to results obtained from larger telescopes and numerical simulations.

  12. High color rendering index white light emitting diodes fabricated from a combination of carbon dots and zinc copper indium sulfide quantum dots

    SciTech Connect (OSTI)

    Sun, Chun; Liu, Wenyan; Zhang, Xiaoyu; Zhang, Yu E-mail: wyu6000@gmail.com; Wang, Yu; Kalytchuk, Sergii; Kershaw, Stephen V.; Rogach, Andrey L.; Zhang, Tieqiang; Zhao, Jun; Yu, William W. E-mail: wyu6000@gmail.com

    2014-06-30

    In a line with most recent trends in developing non-toxic fluorescent nanomaterials, we combined blue emissive carbon dots with green and red emissive zinc copper indium sulfide (ZCIS) core/shell quantum dots (QDs) to achieve white light-emitting diodes (WLEDs) with a high color rendering index of 93. This indicates that ZCIS QDs, with their broad emission bands, can be employed to effectively make up the emission of carbon dots in the yellow and red regions to produce WLEDs in the wide region of color temperature by tuning the volume ratio of these constituting luminophores. Their electroluminescence characteristics including color rendering index, Commission Internationale de l'Eclairage (CIE) color coordinates, and color temperatures were evaluated as a function of forward current. The CIE-1931 chromaticity coordinates of the as-prepared WLEDs, exhibiting good stability, were slightly shifted from (0.321, 0.312) at 10?mA to (0.351, 0.322) at 30?mA, which was mainly caused by the different thermal quenching coefficients of carbon dots and ZCIS QDs.

  13. Semiconductor Quantum Dots and Quantum Dot Arrays and Applications of Multiple Exciton Generation to Third-Generation Photovoltaic Solar Cells

    SciTech Connect (OSTI)

    Nozik, Arthur J.; Beard, Matthew C.; Luther, Joseph M.; Law, Matt; Ellingson, Randy J.; Johnson, Justin C.

    2010-10-14

    Here, we will first briefly summarize the general principles of QD synthesis using our previous work on InP as an example. Then we will focus on QDs of the IV-VI Pb chalcogenides (PbSe, PbS, and PbTe) and Si QDs because these were among the first QDs that were reported to produce multiple excitons upon absorbing single photons of appropriate energy (a process we call multiple exciton generation (MEG)). We note that in addition to Si and the Pb-VI QDs, two other semiconductor systems (III-V InP QDs(56) and II-VI core-shell CdTe/CdSe QDs(57)) were very recently reported to also produce MEG. Then we will discuss photogenerated carrier dynamics in QDs, including the issues and controversies related to the cooling of hot carriers and the magnitude and significance of MEG in QDs. Finally, we will discuss applications of QDs and QD arrays in novel quantum dot PV cells, where multiple exciton generation from single photons could yield significantly higher PV conversion efficiencies.

  14. Multi-stacked InAs/GaAs quantum dots grown with different growth modes for quantum dot solar cells

    SciTech Connect (OSTI)

    Kim, Yeongho; Ban, Keun-Yong Honsberg, Christiana B.

    2015-06-01

    We have studied the material properties and device performance of InAs/GaAs quantum dot solar cells (QDSCs) made using three different QD growth modes: Stranski-Krastanov (S-K), quasi-monolayer (QML), and sub-monolayer (SML) growth modes. All QDSCs show an extended external quantum efficiency (EQE) at near infrared wavelengths of 9501070?nm from the QD absorption. Compared to the S-K and SML QDSCs, the QML QDSC with a higher strain exhibits a poor EQE response in the wavelength region of 300880?nm due to increased non-radiative recombination. The conversion efficiency of the S-K and SML QDSCs exceeds that of the reference cell (13.4%) without QDs due to an enhanced photocurrent (>16% increase) produced by the silicon doped QD stacks. However, as expected from the EQE of the QML QDSC, the increase of strain-induced crystalline defects greatly degrades the photocurrent and open-circuit voltage, leading to the lowest conversion efficiency (8.9%)

  15. The impact of disorder on charge transport in three dimensional quantum dot resonant tunneling structures

    SciTech Connect (OSTI)

    Puthen-Veettil, B. Patterson, R.; Knig, D.; Conibeer, G.; Green, M. A.

    2014-10-28

    Efficient iso-entropic energy filtering of electronic waves can be realized through nanostructures with three dimensional confinement, such as quantum dot resonant tunneling structures. Large-area deployment of such structures is useful for energy selective contacts but such configuration is susceptible to structural disorders. In this work, the transport properties of quantum-dot-based wide-area resonant tunneling structures, subject to realistic disorder mechanisms, are studied. Positional variations of the quantum dots are shown to reduce the resonant transmission peaks while size variations in the device are shown to reduce as well as broaden the peaks. Increased quantum dot size distribution also results in a peak shift to lower energy which is attributed to large dots dominating transmission. A decrease in barrier thickness reduces the relative peak height while the overall transmission increases dramatically due to lower series resistance. While any shift away from ideality can be intuitively expected to reduce the resonance peak, quantification allows better understanding of the tolerances required for fabricating structures based on resonant tunneling phenomena/.

  16. Photoluminescence properties of cadmium-selenide quantum dots embedded in a liquid-crystal polymer matrix

    SciTech Connect (OSTI)

    Tselikov, G. I. Timoshenko, V. Yu.; Plenge, J.; Ruehl, E.; Shatalova, A. M.; Shandryuk, G. A.; Merekalov, A. S.; Tal'roze, R. V.

    2013-05-15

    The photoluminescence properties of cadmium-selenide (CdSe) quantum dots with an average size of {approx}3 nm, embedded in a liquid-crystal polymer matrix are studied. It was found that an increase in the quantum-dot concentration results in modification of the intrinsic (exciton) photoluminescence spectrum in the range 500-600 nm and a nonmonotonic change in its intensity. Time-resolved measurements show the biexponential decay of the photoluminescence intensity with various ratios of fast and slow components depending on the quantum-dot concentration. In this case, the characteristic lifetimes of exciton photoluminescence are 5-10 and 35-50 ns for the fast and slow components, respectively, which is much shorter than the times for colloidal CdSe quantum dots of the same size. The observed features of the photoluminescence spectra and kinetics are explained by the effects of light reabsorption, energy transfer from quantum dots to the liquid-crystal polymer matrix, and the effect of the electronic states at the CdSe/(liquid crystal) interface.

  17. Inhibition of plasmonically enhanced interdot energy transfer in quantum dot solids via photo-oxidation

    SciTech Connect (OSTI)

    Sadeghi, S. M.; Nejat, A.; West, R. G.

    2012-11-15

    We studied the impact of photophysical and photochemical processes on the interdot Forster energy transfer in monodisperse CdSe/ZnS quantum dot solids. For this, we investigated emission spectra of CdSe/ZnS quantum dot solids in the vicinity of gold metallic nanoparticles coated with chromium oxide. The metallic nanoparticles were used to enhance the rate of the energy transfer between the quantum dots, while the chromium oxide coating led to significant increase of their photo-oxidation rates. Our results showed that irradiation of such solids with a laser beam can lead to unique spectral changes, including narrowing and blue shift. We investigate these effects in terms of inhibition of the plasmonically enhanced interdot energy transfer between quantum dots via the chromium-oxide accelerated photo-oxidation process. We demonstrate this considering energy-dependent rate of the interdot energy transfer process, plasmonic effects, and the way photo-oxidation enhances non-radiative decay rates of quantum dots with different sizes.

  18. Test and evaluation document for DOT Specification 7A type A packaging. Volume 1

    SciTech Connect (OSTI)

    Kelly, D L

    1997-08-04

    The US Department of Energy (DOE) has been conducting, through several of its operating contractors, an evaluation and testing program to qualify Type A radioactive material packagings per US Department of Transportation (DOT) Specification 7A (DOT-7A) of the Code of Federal Regulations (CFR), Title 49, Part 178 (49 CFR 178). This document summarizes the evaluation and testing performed for all of the packagings successfully qualified in this program. This document supersedes DOE Evaluation Document for DOT-7A Type A Packaging (Edling 1987), originally issued in 1987 by Monsanto Research Corporation Mound Laboratory (MLM), Miamisburg, Ohio, for the Department of Energy, Security Evaluation Program (I)P-4. Mound Laboratory issued four revisions to the document between November 1988 and December 1989. In September 1989, the program was transferred to Westinghouse Hanford Company (Westinghouse Hanford) in Richland, Washington. One additional revision was issued in March 1990 by Westinghouse Hanford. This revision reflects the earlier material and incorporates a number of changes. Evaluation and testing activities on 1208 three DOT-7A Program Dockets resulted in the qualification of three new packaging configurations, which are incorporated herein and summarized. This document presents approximately 300 different packagings that have been determined to meet the requirements for a DOT-7A, type A packaging per 49 CFR 178.350.

  19. Tunnel-injection GaN quantum dot ultraviolet light-emitting diodes

    SciTech Connect (OSTI)

    Verma, Jai; Kandaswamy, Prem Kumar; Protasenko, Vladimir; Verma, Amit; Grace Xing, Huili; Jena, Debdeep

    2013-01-28

    We demonstrate a GaN quantum dot ultraviolet light-emitting diode that uses tunnel injection of carriers through AlN barriers into the active region. The quantum dot heterostructure is grown by molecular beam epitaxy on AlN templates. The large lattice mismatch between GaN and AlN favors the formation of GaN quantum dots in the Stranski-Krastanov growth mode. Carrier injection by tunneling can mitigate losses incurred in hot-carrier injection in light emitting heterostructures. To achieve tunnel injection, relatively low composition AlGaN is used for n- and p-type layers to simultaneously take advantage of effective band alignment and efficient doping. The small height of the quantum dots results in short-wavelength emission and are simultaneously an effective tool to fight the reduction of oscillator strength from quantum-confined Stark effect due to polarization fields. The strong quantum confinement results in room-temperature electroluminescence peaks at 261 and 340 nm, well above the 365 nm bandgap of bulk GaN. The demonstration opens the doorway to exploit many varied features of quantum dot physics to realize high-efficiency short-wavelength light sources.

  20. Energy levels of double triangular graphene quantum dots

    SciTech Connect (OSTI)

    Liang, F. X.; Jiang, Z. T. Zhang, H. Y.; Li, S.; Lv, Z. T.

    2014-09-28

    We investigate theoretically the energy levels of the coupled double triangular graphene quantum dots (GQDs) based on the tight-binding Hamiltonian model. The double GQDs including the ZZ-type, ZA-type, and AA-type GQDs with the two GQDs having the zigzag or armchair boundaries can be coupled together via different interdot connections, such as the direct coupling, the chains of benzene rings, and those of carbon atoms. It is shown that the energy spectrum of the coupled double GQDs is the amalgamation of those spectra of the corresponding two isolated GQDs with the modification triggered by the interdot connections. The interdot connection is inclined to lift up the degeneracies of the energy levels in different degree, and as the connection changes from the direct coupling to the long chains, the removal of energy degeneracies is suppressed in ZZ-type and AA-type double GQDs, which indicates that the two coupled GQDs are inclined to become decoupled. Then we consider the influences on the spectra of the coupled double GQDs induced by the electric fields applied on the GQDs or the connection, which manifests as the global spectrum redistribution or the local energy level shift. Finally, we study the symmetrical and asymmetrical energy spectra of the double GQDs caused by the substrates supporting the two GQDs, clearly demonstrating how the substrates affect the double GQDs' spectrum. This research elucidates the energy spectra of the coupled double GQDs, as well as the mechanics of manipulating them by the electric field and the substrates, which would be a significant reference for designing GQD-based devices.

  1. Microscopic model for intersubband gain from electrically pumped quantum-dot structures

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Michael, Stephan; Chow, Weng Wah; Schneider, Han Christian

    2014-10-03

    We study theoretically the performance of electrically pumped self-organized quantum dots as a gain material in the mid-infrared range at room temperature. We analyze an AlGaAs/InGaAs based structure composed of dots-in-a-well sandwiched between two quantum wells. We numerically analyze a comprehensive model by combining a many-particle approach for electronic dynamics with a realistic modeling of the electronic states in the whole structure. We investigate the gain both for quasi-equilibrium conditions and current injection. We find, comparing different structures, that steady-state gain can only be realized by an efficient extraction process, which prevents an accumulation of electrons in continuum states, thatmore » make the available scattering pathways through the quantum-dot active region too fast to sustain inversion.« less

  2. Tunnel magnetoresistance and linear conductance of double quantum dots strongly coupled to ferromagnetic leads

    SciTech Connect (OSTI)

    Weymann, Ireneusz

    2015-05-07

    We analyze the spin-dependent linear-response transport properties of double quantum dots strongly coupled to external ferromagnetic leads. By using the numerical renormalization group method, we determine the dependence of the linear conductance and tunnel magnetoresistance on the degree of spin polarization of the leads and the position of the double dot levels. We focus on the transport regime where the system exhibits the SU(4) Kondo effect. It is shown that the presence of ferromagnets generally leads the suppression of the linear conductance due to the presence of an exchange field. Moreover, the exchange field gives rise to a transition from the SU(4) to the orbital SU(2) Kondo effect. We also analyze the dependence of the tunnel magnetoresistance on the double dot levels' positions and show that it exhibits a very nontrivial behavior.

  3. Extraction of inhomogeneous broadening and nonradiative losses in InAs quantum-dot lasers

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chow, Weng W.; Liu, Alan Y.; Gossard, Arthur C.; Bowers, John E.

    2015-10-28

    We present a method to quantify inhomogeneous broadening and nonradiative losses in quantum dot lasers by comparing the gain and spontaneous emission results of a microscopic laser theory with measurements made on 1.3 μm InAs quantum-dot lasers. Calculated spontaneous-emission spectra are first matched to those measured experimentally to determine the inhomogeneous broadening in the experimental samples. This is possible because treatment of carrier scattering at the level of quantum kinetic equations provides the homogeneously broadened spectra without use of free parameters, such as the dephasing rate. Thus we then extract the nonradiative recombination current associated with the quantum-dot active regionmore » from a comparison of measured and calculated gain versus current relations.« less

  4. Enhanced spontaneous emission of CdSe quantum dots in monolithic II-VI pillar microcavities

    SciTech Connect (OSTI)

    Lohmeyer, H.; Kruse, C.; Sebald, K.; Gutowski, J.; Hommel, D.

    2006-08-28

    The emission properties of CdSe/ZnSe quantum dots in ZnSe-based pillar microcavities are studied. All-epitaxial cavities made of ZnSSe and MgS/ZnCdSe superlattices with a single quantum-dot sheet embedded have been grown by molecular beam epitaxy. Pillar structures with diameters down to 500 nm have been realized by focused-ion-beam etching. A pronounced enhancement of the spontaneous emission rate of quantum dots coupling to the fundamental mode of the cavities is found as evidence for the Purcell effect. The enhancement by a factor of up to 3.8 depends systematically on the pillar diameter and thus on the Purcell factor of the individual pillars.

  5. Carrier multiplication detected through transient photocurrent in device-grade films of lead selenide quantum dots

    SciTech Connect (OSTI)

    Gao, Jianbo; Fidler, Andrew F.; Klimov, Victor I.

    2015-09-08

    In carrier multiplication, the absorption of a single photon results in two or more electronhole pairs. Quantum dots are promising materials for implementing carrier multiplication principles in real-life technologies. So far, however, most of research in this area has focused on optical studies of solution samples with yet to be proven relevance to practical devices. We report ultra-fast electro-optical studies of device-grade films of electronically coupled quantum dots that allow us to observe multiplication directly in the photocurrent. Our studies help rationalize previous results from both optical spectroscopy and steady-state photocurrent measurements and also provide new insights into effects of electric field and ligand treatments on multiexciton yields. Importantly, we demonstrate that using appropriate chemical treatments of the films, extra charges produced by carrier multiplication can be extracted from the quantum dots before they are lost to Auger recombination and hence can contribute to photocurrent of practical devices.

  6. Luminescence of CdSe/ZnS quantum dots infiltrated into an opal matrix

    SciTech Connect (OSTI)

    Gruzintsev, A. N. Emelchenko, G. A.; Masalov, V. M.; Yakimov, E. E.; Barthou, C.; Maitre, A.

    2009-02-15

    The effect of the photonic band gap in the photonic crystal, the synthesized SiO{sub 2} opal with embedded CdSe/ZnS quantum dots, on its luminescence in the visible spectral region is studied. It is shown that the position of the photonic band gap in the luminescence and reflectance spectra for the infiltrated opal depends on the diameter of the constituent nanospheres and on the angle of recording the signal. The optimal conditions for embedding the CdSe/ZnS quantum dots from the solution into the opal matrix are determined. It is found that, for the opal-CdSe/ZnS nanocomposites, the emission intensity decreases and the luminescence decay time increases in the spatial directions, in which the spectral positions of the photonic band gap and the luminescence peak of the quantum dots coincide.

  7. Design of quantum dot lattices in amorphous matrices by ion beam irradiation

    SciTech Connect (OSTI)

    Buljan, M.; Bogdanovic-Radovic, I.; Karlusic, M.; Desnica, U. V.; Radic, N.; Jaksic, M.; Salamon, K.; Drazic, G.; Bernstorff, S.; Holy, V.

    2011-10-15

    We report on the highly controllable self-assembly of semiconductor quantum dots and metallic nanoparticles in a solid amorphous matrix, induced by ion beam irradiation of an amorphous multilayer. We demonstrate experimentally and theoretically a possibility to tune the basic structural properties of the quantum dots in a wide range. Furthermore, the sizes, distances, and arrangement type of the quantum dots follow simple equations dependent on the irradiation and the multilayer properties. We present a Monte Carlo model for the simulation and prediction of the structural properties of the materials formed by this method. The presented results enable engineering and simple production of functional materials or simple devices interesting for applications in nanotechnology.

  8. AUTHORIZING THE DOT SPECIFICATION 6M PACKAGING FOR CONTINUED USE AT THE SAVANNAH RIVER SITE

    SciTech Connect (OSTI)

    Watkins, R.; Loftin, B.; Hoang, D.

    2010-03-04

    The U.S. Department of Transportation (DOT) Specification 6M packaging was in extensive use for more than 40 years for in-commerce shipments of Type B quantities of fissile and radioactive material (RAM) across the USA, among the Department of Energy (DOE) laboratories, and between facilities in the DOE production complex. In January 2004, the DOT Research and Special Programs Administration (RSPA) Agency issued a final rule in the Federal Register to ammend requirements in the Hazardous Materials Regulations (HMR) pertaining to the transportation of radioactive materials. The final rule became effective on October 1, 2004. One of those changes discontinued the use of the DOT specification 6M, along with other DOT specification packagings, on October 1, 2008. A main driver for the change was due to the fact that 6M specification packagings were not supported by a Safety Analysis Report for Packagings (SARP) that was compliant with Title 10 of the Code of Federal Regulations (CFR) Part 71 (10 CFR 71). The regulatory rules for the discontinued use have been edited in Title 49 of the CFR Parts 100-185, 2004 edition and thereafter. Prior to October 1, 2008, the use of the 6M within the boundaries of the Savannah River Site (SRS), called an onsite transfer, was governed by an onsite transportation document that referenced 49 CFR Parts 100-185. SRS had to develop an Onsite Safety Assessment (OSA) which was independent of 49 CFR in order to justify the continued use of the DOT Specification 6M for the transfer of radioactive material (RAM) at the SRS after October 1, 2008. This paper will discuss the methodology for and difficulties associated with authorizing the DOT Specification 6M Packaging for continued use at the Savannah River Site.

  9. Observation of the Kondo effect in a spin-3/2 hole quantum dot

    SciTech Connect (OSTI)

    Klochan, O.; Micolich, A. P.; Hamilton, A. R.; Trunov, K.; Reuter, D.; Wieck, A. D.

    2013-12-04

    We report the observation of the Kondo effect in a spin-3/2 hole quantum dot formed near pinch-off in a GaAs quantum wire. We clearly observe two distinctive hallmarks of quantum dot Kondo physics. First, the zero-bias peak in the differential conductance splits an in-plane magnetic field and the splitting is independent of gate voltage. Second, the splitting rate is twice as large as that for the lowest one-dimensional subband. We show that the Zeeman splitting of the zero-bias peak is highly anisotropic and attribute this to the strong spin-orbit interaction for holes in GaAs.

  10. Photo-induced conductance fluctuations in mesoscopic Ge/Si systems with quantum dots

    SciTech Connect (OSTI)

    Stepina, N. P.; Dvurechenskii, A. V.; Nikiforov, A. I.; Moers, J.; Gruetzmacher, D.

    2014-08-20

    We study the evolution of electron transport in strongly localized mesoscopic system with quantum dots under small photon flux. Exploring devices with narrow transport channels lead to the observation of giant fluctuations of the photoconductance, which is attributed to the strong dependence of hopping current on the filling of dots by holes. In our experiments, single-photon mode operation is indicated by the linear dependence of the frequency of photo-induced fluctuations on the light intensity and the step-like response of conductance on the pulse excitation. The effect of the light wavelength, measurement temperature, size of the conductive channel on the device efficiency are considered.

  11. Density-Dependent Carrier Dynamics in a Quantum Dots-in-a-Well

    Office of Scientific and Technical Information (OSTI)

    Heterostructure. (Journal Article) | SciTech Connect Density-Dependent Carrier Dynamics in a Quantum Dots-in-a-Well Heterostructure. Citation Details In-Document Search Title: Density-Dependent Carrier Dynamics in a Quantum Dots-in-a-Well Heterostructure. Abstract not provided. Authors: Chow, Weng W. ; Prasankumar, Rohit P. ; Urayama, Junji ; Attaluri, R. S. ; Shenoi, R. V. ; Krishna, S. ; Taylor, A. J. Publication Date: 2010-11-01 OSTI Identifier: 1121942 Report Number(s): SAND2010-7836J

  12. Temperature dependent photoluminescence and micromapping of multiple stacks InAs quantum dots

    SciTech Connect (OSTI)

    Xu, Ming Jaffr, Alexandre Alvarez, Jos Kleider, Jean-Paul Boutchich, Mohamed; Jittrong, Apichat; Chokamnuai, Thitipong; Panyakeow, Somsak; Kanjanachuchai, Songphol

    2015-02-27

    We utilized temperature dependent photoluminescence (PL) techniques to investigate 1, 3 and 5 stack InGaAs quantum dots (QDs) grown on cross-hatch patterns. PL mapping can well reproduce the QDs distribution as AFM and position dependency of QD growth. It is possible to observe crystallographic dependent PL. The temperature dependent spectra exhibit the QDs energy distribution which reflects the size and shape. The inter-dot carrier coupling effect is observed and translated as a red shift of 120mV on the [110] direction peak is observed at 30K on 1 stack with regards to 3 stacks samples, which is assigned to lateral coupling.

  13. Temperature dependency of the emission properties from positioned In(Ga)As/GaAs quantum dots

    SciTech Connect (OSTI)

    Braun, T.; Schneider, C.; Maier, S.; Forchel, A.; Hfling, S.; Kamp, M.; Igusa, R.; Iwamoto, S.; Arakawa, Y.

    2014-09-15

    In this letter we study the influence of temperature and excitation power on the emission linewidth from site-controlled InGaAs/GaAs quantum dots grown on nanoholes defined by electron beam lithography and wet chemical etching. We identify thermal electron activation as well as direct exciton loss as the dominant intensity quenching channels. Additionally, we carefully analyze the effects of optical and acoustic phonons as well as close-by defects on the emission linewidth by means of temperature and power dependent micro-photoluminescence on single quantum dots with large pitches.

  14. Safety analysis report for packaging: the ORNL DOT specification 6M - special form package

    SciTech Connect (OSTI)

    Schaich, R.W.

    1982-07-01

    The ORNL DOT Specification 6M - Special Form Package was fabricated at the Oak Ridge Nation al Laboratory (ORNL) for the transport of Type B solid non-fissile radioactive materials in special form. The package was evaluated on the basis of tests performed by the Dow Chemical Company, Rocky Flats Division, on the DOT-6M container and special form tests performed on a variety of stainless steel capsules at ORNL by Operations Division personnel. The results of these evaluations demonstrate that the package is in compliance with the applicable regulations for the transport of Type B quantities in special form of non-fissile radioactive materials.

  15. g-factor anisotropy in nanowire-based InAs quantum dots

    SciTech Connect (OSTI)

    D'Hollosy, Samuel; Fábián, Gábor; Baumgartner, Andreas; Schönenberger, Christian; Nygård, Jesper

    2013-12-04

    The determination and control of the electron g-factor in semiconductor quantum dots (QDs) are fundamental prerequisites in modern concepts of spintronics and spin-based quantum computation. We study the dependence of the g-factor on the orientation of an external magnetic field in quantum dots (QDs) formed between two metallic contacts on stacking fault free InAs nanowires. We extract the g-factor from the splitting of Kondo resonances and find that it varies continuously in the range between |g*| = 5 and 15.

  16. Test and evaluation document for DOT Specification 7A Type A Packaging. Revision 3

    SciTech Connect (OSTI)

    1996-01-30

    The US Department of Energy (DOE) has been conducting, through several of its operating contractors, an evaluation and testing program to qualify Type A radioactive material packagings per US Department of Transportation (DOT) Specification 7A (DOT-7A) of the Code of Federal Regulations (CFR), Title 49, Part 178 (49 CFR 178). The program is currently administered by the DOE, Office of Facility Safety Analysis, DOE/EH-32, at DOE-Headquarters (DOE-HQ) in Germantown, Maryland. This document summarizes the evaluation and testing performed for all of the packagings successfully qualified in this program.

  17. Next-Generation "Giant" Quantum Dots: Performance-Engineered for

    Energy Savers [EERE]

    Lighting | Department of Energy "Giant" Quantum Dots: Performance-Engineered for Lighting Next-Generation "Giant" Quantum Dots: Performance-Engineered for Lighting Lead Performer: Los Alamos National Laboratory - Los Alamos, NM Partners: Cree, Inc. - Durham, NC DOE Total Funding: $1,000,366 Cost Share: $250,006 Project Term: 7/1/15 - 6/30/17 Funding Opportunity: SSL R&D Funding Opportunity Announcement (FOA) (DE-FOA-0001171) Project Objective This project seeks to

  18. TiO2 Nanotubes with a ZnO Thin Energy Barrier for Improved Current Efficiency of CdSe Quantum-Dot-Sensitized Solar Cells

    SciTech Connect (OSTI)

    Lee, W.; Kang, S. H.; Kim, J. Y.; Kolekar, G. B.; Sung, Y. E.; Han, S. H.

    2009-01-01

    This paper reports the formation of a thin ZnO energy barrier between a CdSe quantum dot (Q dots) sensitizer and TiO{sub 2} nanotubes (TONTs) for improved current efficiency of Q dot-sensitized solar cells. The formation of a ZnO barrier between TONTs and the Q dot sensitizer increased the short-circuit current under illumination and also reduced the dark current in a dark environment. The power conversion efficiency of Q dot-sensitized TONT solar cells increased by 25.9% in the presence of the ZnO thin layer due to improved charge-collecting efficiency and reduced recombination.

  19. Deep-level transient spectroscopy of InAs/GaAs quantum dot superlattices

    SciTech Connect (OSTI)

    Sobolev, M. M.; Nevedomskii, V. N.; Zolotareva, R. V.; Vasil'ev, A. P.; Ustinov, V. M.

    2014-02-21

    Deep level transient spectroscopy (DLTS) has been applied to study the carrier emission from states of a 10-layer system of tunnel-coupled vertically correlated quantum dots (VCQDs) in p-n InAs/GaAs heterostructures with different widths of GaAs spacers under varied reverse bias (U{sub r}) and filling voltage pulse U{sub f}.

  20. Ligand-Mediated Modification of the Electronic Structure of CdSe Quantum Dots

    SciTech Connect (OSTI)

    Lee, Jonathan R.; Whitley, Heather D.; Meulenberg, Robert W.; Wolcott, Abraham; Zhang, Jin Z.; Prendergast, Peter; Lovingood, Derek D.; Strouse, Geoffrey F.; Ogitsu, Tadashi; Schwegler, Eric; Terminello, Louis J.; Van Buuren, Tony W.

    2012-05-18

    X-ray absorption spectroscopy and ab initio modeling of the experimental spectra have been used to investigate the effects of surface passivation on the unoccupied electronic states of CdSe quantum dots (QDs). Significant differences are observed in the unoccupied electronic structure of the CdSe QDs, which are shown to arise from variations in specific ligand-surface bonding interactions.

  1. Synthesis and optical properties of cadmium selenide quantum dots for white light-emitting diode application

    SciTech Connect (OSTI)

    Xu, Xianmei; Wang, Yilin; Gule, Teri; Luo, Qiang [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China); Zhou, Liya, E-mail: zhouliyatf@163.com [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China); Gong, Fuzhong [School of Chemistry and Chemical Engineering, Guangxi University, Nanning 53000 (China)

    2013-03-15

    Highlights: ? Stable CdSe QDs were synthesized by the one-step and two-level process respectively. ? The fabricated white LEDs show good white balance. ? CdSe QDs present well green to yellow band luminescence. ? CdSe QDs displayed a broad excitation band. - Abstract: Yellow light-emitting cadmium selenide quantum dots were synthesized using one-step and two-step methods in an aqueous medium. The structural luminescent properties of these quantum dots were investigated. The obtained cadmium selenide quantum dots displayed a broad excitation band suitable for blue or near-ultraviolet light-emitting diode applications. White light-emitting diodes were fabricated by coating the cadmium selenide samples onto a 460 nm-emitting indium gallium nitrite chip. Both samples exhibited good white balance. Under a 20 mA working current, the white light-emitting diode fabricated via the one-step and two-step methods showed Commission Internationale de lclairage coordinates at (0.27, 0.23) and (0.27, 0.33), respectively, and a color rendering index equal to 41 and 37, respectively. The one-step approach was simpler, greener, and more effective than the two-step approach. The one-step approach can be enhanced by combining cadmium selenide quantum dots with proper phosphors.

  2. Theoretical performance of solar cell based on mini-bands quantum dots

    SciTech Connect (OSTI)

    Aly, Abou El-Maaty M. E-mail: ashraf.nasr@gmail.com; Nasr, A. E-mail: ashraf.nasr@gmail.com

    2014-03-21

    The tremendous amount of research in solar energy is directed toward intermediate band solar cell for its advantages compared with the conventional solar cell. The latter has lower efficiency because the photons have lower energy than the bandgap energy and cannot excite mobile carriers from the valence band to the conduction band. On the other hand, if mini intermediate band is introduced between the valence and conduction bands, then the smaller energy photons can be used to promote charge carriers transfer to the conduction band and thereby the total current increases while maintaining a large open circuit voltage. In this article, the influence of the new band on the power conversion efficiency for structure of quantum dots intermediate band solar cell is theoretically investigated and studied. The time-independent Schrdinger equation is used to determine the optimum width and location of the intermediate band. Accordingly, achievement of a maximum efficiency by changing the width of quantum dots and barrier distances is studied. Theoretical determination of the power conversion efficiency under the two different ranges of QD width is presented. From the obtained results, the maximum power conversion efficiency is about 70.42%. It is carried out for simple cubic quantum dot crystal under fully concentrated light. It is strongly dependent on the width of quantum dots and barrier distances.

  3. Determining the exact number of dye molecules attached to colloidal CdSe/ZnS quantum dots in Frster resonant energy transfer assemblies

    SciTech Connect (OSTI)

    Kaiser, Uwe; Jimenez de Aberasturi, Dorleta; Vzquez-Gonzlez, Margarita; Carrillo-Carrion, Carolina; Niebling, Tobias; Parak, Wofgang J.; Heimbrodt, Wolfram

    2015-01-14

    Semiconductor quantum dots functionalized with organic dye molecules are important tools for biological sensor applications. Energy transfer between the quantum dot and the attached dyes can be utilized for sensing. Though important, the determination of the real number of dye molecules attached per quantum dot is rather difficult. In this work, a method will be presented to determine the number of ATTO-590 dye molecules attached to CdSe/ZnS quantum dots based on time resolved spectral analysis. The energy transfer from the excited quantum dot to the attached ATTO-590 dye leads to a reduced lifetime of the quantum dot's excitons. The higher the concentration of dye molecules, the shorter the excitonic lifetime becomes. However, the number of dye molecules attached per quantum dot will vary. Therefore, for correctly explaining the decay of the luminescence upon photoexcitation of the quantum dot, it is necessary to take into account the distribution of the number of dyes attached per quantum dot. A Poisson distribution of the ATTO-590 dye molecules not only leads to excellent agreement between experimental and theoretical decay curves but also additionally yields the average number of dye molecules attached per quantum dot. In this way, the number of dyes per quantum dot can be conveniently determined.

  4. Investigation of size dependent structural and optical properties of thin films of CdSe quantum dots

    SciTech Connect (OSTI)

    Sharma, Madhulika; Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay, Powai, Mumbai 400076 ; Sharma, A.B.; Mishra, N.; Pandey, R.K.

    2011-03-15

    Research highlights: {yields} CdSe q-dots have been synthesized using simple chemical synthesis route. {yields} Thin film of CdSe quantum dots exhibited self-organized growth. {yields} Size dependent blue shift observed in the absorption edge of CdSe nanocrystallites. {yields} PL emission band corresponds to band edge luminescence and defect luminescence. {yields} Organized growth led to enhancement in luminescence yield of smaller size Q-dots. -- Abstract: Cadmium selenide (CdSe) quantum dots were grown on indium tin oxide substrate using wet chemical technique for possible application as light emitting devices. The structural, morphological and luminescence properties of the as deposited thin films of CdSe Q-dot have been investigated, using X-ray diffraction, transmission electron microscopy, atomic force microscopy and optical and luminescence spectroscopy. The quantum dots have been shown to deposit in an organized array on ITO/glass substrate. The as grown Q-dots exhibited size dependent blue shift in the absorption edge. The effect of quantum confinement also manifested as a blue shift of photoluminescence emission. It is shown that the nanocrystalline CdSe exhibits intense photoluminescence as compared to the large grained polycrystalline CdSe films.

  5. Effect of matrix on InAs self-organized quantum dots on InP substrate

    SciTech Connect (OSTI)

    Ustinov, V.M.; Weber, E.R.; Ruvimov, S.; Liliental-Weber, Z.; Zhukov, A.E.; Egorov, A.Y.; Kovsh, A.R.; Tsatsulnikov, A.F.; Kopev, P.S.

    1998-01-01

    InAs self-organized quantum dots in In{sub 0.53}Ga{sub 0.47}As and In{sub 0.52}Al{sub 0.48}As matrices have been grown on InP substrates by molecular beam epitaxy. The dot size in InGaAs has been found to be 3{endash}4 times larger, but the areal density about an order of magnitude smaller than that in InAlAs. Low-temperature photoluminescence (PL) of the InAs/InGaAs quantum dots is characterized by a narrow (35 meV) PL line as compared to that of InAs/InAlAs quantum dots (170 meV). Quantum dot formation increases the carrier localization energy as compared to quantum well structures with the same InAs thickness in a similar manner for both InAs/InGaAs and InAs/InAlAs structures. The effect of the barrier band gap on the optical transition energy is qualitatively the same for quantum well and quantum dot structures. The results demonstrate a possibility of controlling the quantum dot emission wavelength by varying the matrix composition. {copyright} {ital 1998 American Institute of Physics.}

  6. A theoretical analysis of the optical absorption properties in one-dimensional InAs/GaAs quantum dot superlattices

    SciTech Connect (OSTI)

    Kotani, Teruhisa; Birner, Stefan; Lugli, Paolo; Hamaguchi, Chihiro

    2014-04-14

    We present theoretical investigations of miniband structures and optical properties of InAs/GaAs one-dimensional quantum dot superlattices (1D-QDSLs). The calculation is based on the multi-band kp theory, including the conduction and valence band mixing effects, the strain effect, and the piezoelectric effect; all three effects have periodic boundary conditions. We find that both the electronic and optical properties of the 1D-QDSLs show unique states which are different from those of well known single quantum dots (QDs) or quantum wires. We predict that the optical absorption spectra of the 1D-QDSLs strongly depend on the inter-dot spacing because of the inter-dot carrier coupling and changing strain states, which strongly influence the conduction and valence band potentials. The inter-miniband transitions form the absorption bands. Those absorption bands can be tuned from almost continuous (closely stacked QD case) to spike-like shape (almost isolated QD case) by changing the inter-dot spacing. The polarization of the lowest absorption peak for the 1D-QDSLs changes from being parallel to the stacking direction to being perpendicular to the stacking direction as the inter-dot spacing increases. In the case of closely stacked QDs, in-plane anisotropy, especially [110] and [11{sup }0] directions also depend on the inter-dot spacing. Our findings and predictions will provide an additional degree of freedom for the design of QD-based optoelectronic devices.

  7. The use of bulk states to accelerate the band edge state calculation of a semiconductor quantum dot

    SciTech Connect (OSTI)

    Voemel, Christof . E-mail: voemel@eecs.berkeley.edu; Tomov, Stanimire Z. . E-mail: tomov@cs.utk.edu; Wang, Lin-Wang . E-mail: LWWang@lbl.gov; Marques, Osni A. . E-mail: OAMarques@lbl.gov; Dongarra, Jack J. . E-mail: dongarra@cs.utk.edu

    2007-05-01

    We present a new technique to accelerate the convergence of the folded spectrum method in empirical pseudopotential band edge state calculations for colloidal quantum dots. We use bulk band states of the materials constituent of the quantum dot to construct initial vectors and a preconditioner. We apply these to accelerate the convergence of the folded spectrum method for the interior states at the top of the valence and the bottom of the conduction band. For large CdSe quantum dots, the number of iteration steps until convergence decreases by about a factor of 4 compared to previous calculations.

  8. Enhanced photorefractive performance in CdSe quantum-dot-dispersed poly(styrene-co-acrylonitrile) polymers

    SciTech Connect (OSTI)

    Li Xiangping; Embden, Joel van; Chon, James W. M.; Gu Min; Evans, Richard A.

    2010-06-21

    This paper reports on the enhanced photorefractive behavior of a CdSe quantum-dot-dispersed less expensive polymer of poly(styrene-co-acrylonitrile). The capability of CdSe quantum dots used as photosensitizers and the associated photorefractive performance are characterized through a photocurrent experiment and a two-beam coupling experiment, respectively. An enhanced two-beam coupling gain coefficient of 12.2 cm{sup -1} at 46 V/mum was observed owning to the reduced potential barrier. The photorefractive performance per CdSe quantum dot is three orders of magnitude higher than that in the sample sensitized by trinitrofluorenone in poly(styrene-co-acrylonitrile), and almost ten times higher than that in the CdSe quantum-dot-sensitized poly(N-vinylcarbazole) polymers.

  9. Local student receives Y-12-sponsored scholarship | Y-12 National

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Security Complex Local student receives ... Local student receives Y-12-sponsored scholarship Posted: August 22, 2011 - 1:56pm For a second consecutive year, B&W Y-12 sponsored a $2,500 Tennessee Valley Technology Council (TVTC) Scholarship to support a local student "passionate about technology." This year's winner is Elijah Harris. Harris will be entering the University of Tennessee’s College of Agriculture this fall with plans to major in biosystems engineering. Concerns

  10. Engineering Division Safety Officer Named: Message From Will Oren |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Jefferson Lab Engineering Division Safety Officer Named: Message From Will Oren All, Since Henry Robertson took on leadership of the Safety Systems Group we have had Harry Fanning, Accelerator Division Safety Officer, filling in as the Engineering DSO. Harry has done an outstanding job in this role and I would like to thank him for his services over the past year. I have recently reached an agreement with Paul Collins and his supervisor, for Paul to become the Engineering DSO starting Jan 4,

  11. Microsoft PowerPoint - Pete H's 2007 SWPA Conf Pres(NWK Proj's Impact Fed Power).ppt

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AmerenUE, Bagnell Dam FERC Re-licensing Impacts at Harry S. Truman AmerenUE, Bagnell Dam FERC Re-licensing Impacts at Harry S. Truman * FERC recommended AmerenUE initiate discussions with Kansas City District on revising the existing MOA for releases from Truman. * The new FERC license recommended ramp down rates for flood control releases to help prevent bank erosion. * Kansas City District staff met with AmerenUE in late Feb. 2007. * It was explained to AmerenUE that any significant changes to

  12. Probing the structural dependency of photoinduced properties of colloidal quantum dots using metal-oxide photo-active substrates

    SciTech Connect (OSTI)

    Patty, Kira; Campbell, Quinn; Hamilton, Nathan; West, Robert G.; Sadeghi, Seyed M.; Mao, Chuanbin

    2014-09-21

    We used photoactive substrates consisting of about 1 nm coating of a metal oxide on glass substrates to investigate the impact of the structures of colloidal quantum dots on their photophysical and photochemical properties. We showed during irradiation these substrates can interact uniquely with such quantum dots, inducing distinct forms of photo-induced processes when they have different cores, shells, or ligands. In particular, our results showed that for certain types of core-shell quantum dot structures an ultrathin layer of a metal oxide can reduce suppression of quantum efficiency of the quantum dots happening when they undergo extensive photo-oxidation. This suggests the possibility of shrinking the sizes of quantum dots without significant enhancement of their non-radiative decay rates. We show that such quantum dots are not influenced significantly by Coulomb blockade or photoionization, while those without a shell can undergo a large amount of photo-induced fluorescence enhancement via such blockade when they are in touch with the metal oxide.

  13. Low-temperature transport in ac-driven quantum dots in the Kondo regime

    SciTech Connect (OSTI)

    Lopez, Rosa; Aguado, Ramon; Platero, Gloria; Tejedor, Carlos

    2001-08-15

    We present a fully nonequilibrium calculation of the low-temperature transport properties of a quantum dot in the Kondo regime when an ac potential is applied to the gate. We solve a time-dependent Anderson model with finite on-site Coulomb interaction. The interaction self-energy is calculated up to second order in perturbation theory in the on-site interaction, in the context of the Keldysh nonequilibrium technique, and the effect of the ac voltage is taken into account exactly for all ranges of ac frequencies and ac intensities. The obtained linear conductance and time-averaged density of states of the quantum dot evolve in a nontrivial way as a function of the ac frequency and ac intensity of the harmonic modulation.

  14. Carbon quantum dots coated BiVO{sub 4} inverse opals for enhanced photoelectrochemical hydrogen generation

    SciTech Connect (OSTI)

    Nan, Feng; Shen, Mingrong; Fang, Liang E-mail: lfang@suda.edu.cn; Kang, Zhenhui E-mail: lfang@suda.edu.cn; Wang, Junling

    2015-04-13

    Carbon quantum dots (CQDs) coated BiVO{sub 4} inverse opal (io-BiVO{sub 4}) structure that shows dramatic improvement of photoelectrochemical hydrogen generation has been fabricated using electrodeposition with a template. The io-BiVO{sub 4} maximizes photon trapping through slow light effect, while maintaining adequate surface area for effective redox reactions. CQDs are then incorporated to the io-BiVO{sub 4} to further improve the photoconversion efficiency. Due to the strong visible light absorption property of CQDs and enhanced separation of the photoexcited electrons, the CQDs coated io-BiVO{sub 4} exhibit a maximum photo-to-hydrogen conversion efficiency of 0.35%, which is 6 times higher than that of the pure BiVO{sub 4} thin films. This work is a good example of designing composite photoelectrode by combining quantum dots and photonic crystal.

  15. Tunable Quantum Dot Solids: Impact of Interparticle Interactions on Bulk Properties

    SciTech Connect (OSTI)

    Sinclair, Michael B.; Fan, Hongyou; Brener, Igal; Liu, Sheng; Luk, Ting S.; Li, Binsong

    2015-09-01

    QD-solids comprising self-assembled semiconductor nanocrystals such as CdSe are currently under investigation for use in a wide array of applications including light emitting diodes, solar cells, field effect transistors, photodetectors, and biosensors. The goal of this LDRD project was develop a fundamental understanding of the relationship between nanoparticle interactions and the different regimes of charge and energy transport in semiconductor quantum dot (QD) solids. Interparticle spacing was tuned through the application of hydrostatic pressure in a diamond anvil cell, and the impact on interparticle interactions was probed using x-ray scattering and a variety of static and transient optical spectroscopies. During the course of this LDRD, we discovered a new, previously unknown, route to synthesize semiconductor quantum wires using high pressure sintering of self-assembled quantum dot crystals. We believe that this new, pressure driven synthesis approach holds great potential as a new tool for nanomaterials synthesis and engineering.

  16. Pulsed laser deposition of Mn doped CdSe quantum dots for improved solar cell performance

    SciTech Connect (OSTI)

    Dai, Qilin; Wang, Wenyong E-mail: jtang2@uwyo.edu; Tang, Jinke E-mail: jtang2@uwyo.edu; Sabio, Erwin M.

    2014-05-05

    In this work, we demonstrate (1) a facile method to prepare Mn doped CdSe quantum dots (QDs) on Zn{sub 2}SnO{sub 4} photoanodes by pulsed laser deposition and (2) improved device performance of quantum dot sensitized solar cells of the Mn doped QDs (CdSe:Mn) compared to the undoped QDs (CdSe). The band diagram of photoanode Zn{sub 2}SnO{sub 4} and sensitizer CdSe:Mn QD is proposed based on the incident-photon-to-electron conversion efficiency (IPCE) data. Mn-modified band structure leads to absorption at longer wavelengths than the undoped CdSe QDs, which is due to the exchange splitting of the CdSe:Mn conduction band by the Mn dopant. Three-fold increase in the IPCE efficiency has also been observed for the Mn doped samples.

  17. Final LDRD report : infrared detection and power generation using self-assembled quantum dots.

    SciTech Connect (OSTI)

    Cederberg, Jeffrey George; Ellis, Robert; Shaner, Eric Arthur

    2008-02-01

    Alternative solutions are desired for mid-wavelength and long-wavelength infrared radiation detection and imaging arrays. We have investigated quantum dot infrared photodetectors (QDIPs) as a possible solution for long-wavelength infrared (8 to 12 {mu}m) radiation sensing. This document provides a summary for work done under the LDRD 'Infrared Detection and Power Generation Using Self-Assembled Quantum Dots'. Under this LDRD, we have developed QDIP sensors and made efforts to improve these devices. While the sensors fabricated show good responsivity at 80 K, their detectivity is limited by high noise current. Following efforts concentrated on how to reduce or eliminate this problem, but with no clear path was identified to the desired performance improvements.

  18. Sandia Develops a Synthesis of Quantum Dots that Increases the Quantum

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Yield to 95.5% a Synthesis of Quantum Dots that Increases the Quantum Yield to 95.5% - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery

  19. Radiative Lifetimes of Zincblende CdSe/CdS Quantum Dots

    SciTech Connect (OSTI)

    Gong, Ke; Martin, James E.; Shea-Rohwer, Lauren E.; Lu, Ping; Kelley, David F.

    2015-01-02

    Recent synthetic advances have made available very monodisperse zincblende CdSe/CdS quantum dots having near-unity photoluminescence quantum yields. Because of the absence of nonradiative decay pathways, accurate values of the radiative lifetimes can be obtained from time-resolved PL measurements. Radiative lifetimes can also be obtained from the Einstein relations, using the static absorption spectra and the relative thermal populations in the angular momentum sublevels. We found that one of the inputs into these calculations is the shell thickness, and it is useful to be able to determine shell thickness from spectroscopic measurements. We use an empirically corrected effective mass model to produce a map of exciton wavelength as a function of core size and shell thickness. These calculations use an elastic continuum model and the known lattice and elastic constants to include the effect of lattice strain on the band gap energy. The map is in agreement with the known CdSe sizing curve and with the shell thicknesses of zincblende core/shell particles obtained from TEM images. Furthermore, if seleniumsulfur diffusion is included and lattice strain is omitted from the calculation then the resulting map is appropriate for wurtzite CdSe/CdS quantum dots synthesized at high temperatures, and this map is very similar to one previously reported ( J. Am. Chem. Soc. 2009,, 131, 14299). Radiative lifetimes determined from time-resolved measurements are compared to values obtained from the Einstein relations, and found to be in excellent agreement. For a specific core size (2.64 nm diameter, in the present case), radiative lifetimes are found to decrease with increasing shell thickness. This is similar to the size dependence of one-component CdSe quantum dots and in contrast to the size dependence in type-II quantum dots.

  20. Radiative lifetimes of zincblende CdSe/CdS quantum dots

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gong, Ke; Martin, James E.; Shea-Rohwer, Lauren E.; Lu, Ping; Kelley, David F.

    2015-01-02

    Recent synthetic advances have made available very monodisperse zincblende CdSe/CdS quantum dots having near-unity photoluminescence quantum yields. Because of the absence of nonradiative decay pathways, accurate values of the radiative lifetimes can be obtained from time-resolved PL measurements. Radiative lifetimes can also be obtained from the Einstein relations, using the static absorption spectra and the relative thermal populations in the angular momentum sublevels. We found that one of the inputs into these calculations is the shell thickness, and it is useful to be able to determine shell thickness from spectroscopic measurements. We use an empirically corrected effective mass model tomore » produce a “map” of exciton wavelength as a function of core size and shell thickness. These calculations use an elastic continuum model and the known lattice and elastic constants to include the effect of lattice strain on the band gap energy. The map is in agreement with the known CdSe sizing curve and with the shell thicknesses of zincblende core/shell particles obtained from TEM images. Furthermore, if selenium–sulfur diffusion is included and lattice strain is omitted from the calculation then the resulting map is appropriate for wurtzite CdSe/CdS quantum dots synthesized at high temperatures, and this map is very similar to one previously reported (J. Am. Chem. Soc. 2009, 131, 14299). Radiative lifetimes determined from time-resolved measurements are compared to values obtained from the Einstein relations, and found to be in excellent agreement. For a specific core size (2.64 nm diameter, in the present case), radiative lifetimes are found to decrease with increasing shell thickness. Thus, this is similar to the size dependence of one-component CdSe quantum dots and in contrast to the size dependence in type-II quantum dots.« less

  1. Tuning photoluminescence of reduced graphene oxide quantum dots from blue to purple

    SciTech Connect (OSTI)

    Liu, Fuchi; Tang, Tao; Feng, Qian; Li, Ming; Liu, Yuan; Tang, Nujiang Zhong, Wei; Du, Youwei

    2014-04-28

    Reduced graphene oxide quantum dots (rGOQDs) were synthesized by annealing GOQDs in H{sub 2} atmosphere. The photoluminescence (PL) properties of GOQDs and the rGOQDs samples were investigated. The results showed that compared to GOQDs, a blue to purple tunable PL of rGOQDs can be obtained by regulating the annealing temperature. The increase fraction of the newly formed isolated sp{sup 2} clusters may be responsible for the observed tunable PL.

  2. Ab Initio Simulation of Charge Transfer at the Semiconductor Quantum Dot/TiO 2 Interface in Quantum Dot-Sensitized Solar Cells

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xin, Xukai; Li, Bo; Jung, Jaehan; Yoon, Young Jun; Biswas, Rana; Lin, Zhiqun

    2014-07-24

    Quantum dot-sensitized solar cells (QDSSCs) have emerged as a promising solar architecture for next-generation solar cells. The QDSSCs exhibit a remarkably fast electron transfer from the quantum dot (QD) donor to the TiO2 acceptor with size quantization properties of QDs that allows for the modulation of band energies to control photoresponse and photoconversion efficiency of solar cells. In order to understand the mechanisms that underpin this rapid charge transfer, the electronic properties of CdSe and PbSe QDs with different sizes on the TiO2 substrate are simulated using a rigorous ab initio density functional method. Our method capitalizes on localized orbitalmore » basis set, which is computationally less intensive. Quite intriguingly, a remarkable set of electron bridging states between QDs and TiO2 occurring via the strong bonding between the conduction bands of QDs and TiO2 is revealed. Such bridging states account for the fast adiabatic charge transfer from the QD donor to the TiO2 acceptor, and may be a general feature for strongly coupled donor/acceptor systems. All the QDs/TiO2 systems exhibit type II band alignments, with conduction band offsets that increase with the decrease in QD size. This facilitates the charge transfer from QDs donors to TiO2 acceptors and explains the dependence of the increased charge transfer rate with the decreased QD size.« less

  3. Interdot Coulomb correlation effects and spin-orbit coupling in two carbon nanotube quantum dots

    SciTech Connect (OSTI)

    Wang, Zhen-Hua; Kuang, Xiao-Yu Zhong, Ming-Min; Shao, Peng; Li, Hui

    2014-01-28

    Transport properties of the two-level Kondo effect involving spin, orbital, and pseudospin degrees of freedom are examined in a parallel carbon nanotube double quantum dot with a sufficient interdot Coulomb interaction and small interdot tunneling. The interdot Coulomb correlation effects are taken into account, and it plays an important role in forming bonding and antibonding states. Attached to ferromagnetic leads, the Kondo effect is observed at the interdot Coulomb blockade region with degeneracy of spin, orbital, and pseudospin degrees of freedom. A crossover from a two-level Kondo state involving the fivefold degeneracy of the double quantum dots to an SU(4) spin-orbit Kondo state and to an SU(2) spin-Kondo effect is demonstrated. At finite magnetic field, the splitting of the spin, orbital, and pseudospin Kondo resonance can be restored. For finite intradot Coulomb interaction U, there is a competition between the single-dot Kondo effect and the antiferromagnetic exchange coupling J{sub AFM}, resulting in the suppression of the Kondo resonance. Moreover, both the J{sub AFM} and the Zeeman interactions compete, leading to need a much higher value of the magnetic field to compensate for the Kondo splitting.

  4. Evaluating charge noise acting on semiconductor quantum dots in the circuit quantum electrodynamics architecture

    SciTech Connect (OSTI)

    Basset, J.; Stockklauser, A.; Jarausch, D.-D.; Frey, T.; Reichl, C.; Wegscheider, W.; Wallraff, A.; Ensslin, K.; Ihn, T.

    2014-08-11

    We evaluate the charge noise acting on a GaAs/GaAlAs based semiconductor double quantum dot dipole-coupled to the voltage oscillations of a superconducting transmission line resonator. The in-phase (I) and the quadrature (Q) components of the microwave tone transmitted through the resonator are sensitive to charging events in the surrounding environment of the double dot with an optimum sensitivity of 8.510{sup ?5}?e/?(Hz). A low frequency 1/f type noise spectrum combined with a white noise level of 6.610{sup ?6} e{sup 2}/Hz above 1?Hz is extracted, consistent with previous results obtained with quantum point contact charge detectors on similar heterostructures. The slope of the 1/f noise allows to extract a lower bound for the double-dot charge qubit dephasing rate which we compare to the one extracted from a Jaynes-Cummings Hamiltonian approach. The two rates are found to be similar emphasizing that charge noise is the main source of dephasing in our system.

  5. Carrier multiplication detected through transient photocurrent in device-grade films of lead selenide quantum dots

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gao, Jianbo; Fidler, Andrew F.; Klimov, Victor I.

    2015-09-08

    In carrier multiplication, the absorption of a single photon results in two or more electron–hole pairs. Quantum dots are promising materials for implementing carrier multiplication principles in real-life technologies. So far, however, most of research in this area has focused on optical studies of solution samples with yet to be proven relevance to practical devices. We report ultra-fast electro-optical studies of device-grade films of electronically coupled quantum dots that allow us to observe multiplication directly in the photocurrent. Our studies help rationalize previous results from both optical spectroscopy and steady-state photocurrent measurements and also provide new insights into effects ofmore » electric field and ligand treatments on multiexciton yields. Importantly, we demonstrate that using appropriate chemical treatments of the films, extra charges produced by carrier multiplication can be extracted from the quantum dots before they are lost to Auger recombination and hence can contribute to photocurrent of practical devices.« less

  6. Enhancement of photoluminescence in ZnS/ZnO quantum dots interfacial heterostructures

    SciTech Connect (OSTI)

    Rajalakshmi, M.; Sohila, S.; Ramesh, R.; Bhalerao, G.M.

    2012-09-15

    Highlights: ? ZnS/ZnO quantum dots (QDs) were synthesized by controlled oxidation of ZnS nanoparticles. ? Interfacial heterostructure formation of ZnS/ZnO QDs is seen in HRTEM. ? Enormous enhancement of UV emission (?10 times) in ZnS/ZnO QDs heterostructure is observed. ? Phonon confinement effect is seen in the Raman spectrum. -- Abstract: ZnS/ZnO quantum dots (QDs) were synthesized by controlled oxidation of ZnS nanoparticles. HRTEM image showed small nanocrystals of size 4 nm and the magnified image of single quantum dot shows interfacial heterostructure formation. The optical absorption spectrum shows a blue shift of 0.19 and 0.23 eV for ZnO and ZnS QDs, respectively. This is due to the confinement of charge carries within the nanostructures. Enormous enhancement in UV emission (10 times) is reported which is attributed to interfacial heterostructure formation. Raman spectrum shows phonons of wurtzite ZnS and ZnO. Phonon confinement effect is seen in the Raman spectrum wherein LO phonon peaks of ZnS and ZnO are shifted towards lower wavenumber side and are broadened.

  7. Effect of Bi isovalent dopants on the formation of homogeneous coherently strained InAs quantum dots in GaAs matrices

    SciTech Connect (OSTI)

    Peleshchak, R. M.; Guba, S. K.; Kuzyk, O. V.; Kurilo, I. V.; Dankiv, O. O.

    2013-03-15

    The distribution of hydrostatic strains in Bi{sup 3+}-doped InAs quantum dots embedded in a GaAs matrix are calculated in the context of the deformation-potential model. The dependences of strains in the material of spherical InAs quantum dots with substitutional (Bi {yields} As) and interstitial (Bi) impurities on the quantum-dot size are derived. The qualitative correlation of the model with the experiment is discussed. The data on the effect of doping on the morphology of self-assembled InAs:Bi quantum dots in a GaAs matrix are obtained.

  8. Pseudopotential study of electron-hole excitations in colloidal free-standing InAs quantum dots

    SciTech Connect (OSTI)

    Williamson, A. J.; Zunger, Alex

    2000-01-15

    Excitonic spectra are calculated for free-standing, surface passivated, InAs quantum dots using atomic pseudopotentials for the single-particle states and screened Coulomb interactions for the two-body terms. We present an analysis of the single particle states involved in each excitation in terms of their angular momenta and Bloch-wave parentage. We find that (i) in agreement with other pseudopotential studies of CdSe and InP quantum dots, but in contrast to k{center_dot}p calculations, the dot wave functions exhibit strong odd-even angular momentum envelope function mixing (e.g., s with p) and large valence-conduction coupling. (ii) While the pseudopotential approach produced very good agreement with experiment for free-standing, colloidal CdSe and InP dots, and for self-assembled (GaAs-embedded) InAs dots, here the predicted spectrum does not agree well with the measured (ensemble average over dot sizes) spectra. (1) Our calculated excitonic gap is larger than the photoluminescence measured one, and (2) while the spacing between the lowest excitons is reproduced, the spacings between higher excitons is not fit well. Discrepancy (1) could result from surface state emission. As for (2), agreement is improved when account is taken of the finite-size distribution in the experimental data. (iii) We find that the single-particle gap scales as R{sup -1.01} (not R{sup -2}), that the screened (unscreened) electron-hole Coulomb interaction scales as R{sup -1.79} (R{sup -0.7}), and that the excitonic gap scales as R{sup -0.9}. These scaling laws are different from those expected from simple models. (c) 2000 The American Physical Society.

  9. Lifetime and Polarization of the Radiative Decay of Excitons, Biexcitons, and Trions in CdSe Nanocrystal Quantum Dots

    SciTech Connect (OSTI)

    Califano, M.; Franceschetti, A.; Zunger, A.

    2007-01-01

    Using the pseudopotential configuration-interaction method, we calculate the intrinsic lifetime and polarization of the radiative decay of single excitons (X), positive and negative trions (X{sup +} and X{sup -}), and biexcitons (XX) in CdSe nanocrystal quantum dots. We investigate the effects of the inclusion of increasingly more complex many-body treatments, starting from the single-particle approach and culminating with the configuration-interaction scheme. Our configuration-interaction results for the size dependence of the single-exciton radiative lifetime at room temperature are in excellent agreement with recent experimental data. We also find the following. (i) Whereas the polarization of the bright exciton emission is always perpendicular to the hexagonal c axis, the polarization of the dark exciton switches from perpendicular to parallel to the hexagonal c axis in large dots, in agreement with experiment. (ii) The ratio of the radiative lifetimes of mono- and biexcitons (X):(XX) is {approx}1:1 in large dots (R=19.2 {angstrom}). This ratio increases with decreasing nanocrystal size, approaching 2 in small dots (R=10.3 {angstrom}). (iii) The calculated ratio (X{sup +}):(X{sup -}) between positive and negative trion lifetimes is close to 2 for all dot sizes considered.

  10. Ab Initio Simulation of Charge Transfer at the Semiconductor Quantum Dot/TiO 2 Interface in Quantum Dot-Sensitized Solar Cells

    SciTech Connect (OSTI)

    Xin, Xukai; Li, Bo; Jung, Jaehan; Yoon, Young Jun; Biswas, Rana; Lin, Zhiqun

    2014-07-24

    Quantum dot-sensitized solar cells (QDSSCs) have emerged as a promising solar architecture for next-generation solar cells. The QDSSCs exhibit a remarkably fast electron transfer from the quantum dot (QD) donor to the TiO2 acceptor with size quantization properties of QDs that allows for the modulation of band energies to control photoresponse and photoconversion efficiency of solar cells. In order to understand the mechanisms that underpin this rapid charge transfer, the electronic properties of CdSe and PbSe QDs with different sizes on the TiO2 substrate are simulated using a rigorous ab initio density functional method. Our method capitalizes on localized orbital basis set, which is computationally less intensive. Quite intriguingly, a remarkable set of electron bridging states between QDs and TiO2 occurring via the strong bonding between the conduction bands of QDs and TiO2 is revealed. Such bridging states account for the fast adiabatic charge transfer from the QD donor to the TiO2 acceptor, and may be a general feature for strongly coupled donor/acceptor systems. All the QDs/TiO2 systems exhibit type II band alignments, with conduction band offsets that increase with the decrease in QD size. This facilitates the charge transfer from QDs donors to TiO2 acceptors and explains the dependence of the increased charge transfer rate with the decreased QD size.

  11. Carrier dynamics in inhomogeneously broadened InAs/AlGaInAs/InP quantum-dot semiconductor optical amplifiers

    SciTech Connect (OSTI)

    Karni, O. Mikhelashvili, V.; Eisenstein, G.; Kuchar, K. J.; Capua, A.; S?k, G.; Misiewicz, J.; Ivanov, V.; Reithmaier, J. P.

    2014-03-24

    We report on a characterization of fundamental gain dynamics in recently developed InAs/InP quantum-dot semiconductor optical amplifiers. Multi-wavelength pump-probe measurements were used to determine gain recovery rates, following a powerful optical pump pulse, at various wavelengths for different bias levels and pump excitation powers. The recovery was dominated by coupling between the electronic states in the quantum-dots and the high energy carrier reservoir via capture and escape mechanisms. These processes determine also the wavelength dependencies of gain saturation depth and the asymptotic gain recovery level. Unlike quantum-dash amplifiers, these quantum-dots exhibit no instantaneous gain response, confirming their quasi zero-dimensional nature.

  12. Low-density InP-based quantum dots emitting around the 1.5??m telecom wavelength range

    SciTech Connect (OSTI)

    Yacob, M.; Reithmaier, J. P.; Benyoucef, M.

    2014-01-13

    The authors report on low-density InAs quantum dots (QDs) grown on AlGaInAs surfaces lattice matched to InP using post-growth annealing by solid-source molecular beam epitaxy. Clearly spatially separated QDs with a dot density of about 5??10{sup 8} cm{sup ?2} are obtained by using a special capping technique after the dot formation process. High-resolution micro-photoluminescence performed on optimized QD structures grown on distributed Bragg reflector exhibits single QD emissions around 1.5??m with narrow excitonic linewidth below 50??eV, which can be used as single photon source in the telecom wavelength range.

  13. Highly uniform, multi-stacked InGaAs/GaAs quantum dots embedded in a GaAs nanowire

    SciTech Connect (OSTI)

    Tatebayashi, J. Ota, Y.; Ishida, S.; Nishioka, M.; Iwamoto, S.; Arakawa, Y.

    2014-09-08

    We demonstrate a highly uniform, dense stack of In{sub 0.22}Ga{sub 0.78}As/GaAs quantum dot (QD) structures in a single GaAs nanowire (NW). The size (and hence emission energy) of individual QD is tuned by careful control of the growth conditions based on a diffusion model of morphological evolution of NWs and optical characterization. By carefully tailoring the emission energies of individual QD, dot-to-dot inhomogeneous broadening of QD stacks in a single NW can be as narrow as 9.3?meV. This method provides huge advantages over traditional QD stack using a strain-induced Stranski-Krastanow growth scheme. We show that it is possible to fabricate up to 200 uniform QDs in single GaAs NWs using this growth technique without degradation of the photoluminescence intensity.

  14. Highly polarized light emission by isotropic quantum dots integrated with magnetically aligned segmented nanowires

    SciTech Connect (OSTI)

    Uran, Can; Erdem, Talha; Guzelturk, Burak; Perkgz, Nihan Kosku; Jun, Shinae; Jang, Eunjoo; Demir, Hilmi Volkan

    2014-10-06

    In this work, we demonstrate a proof-of-concept system for generating highly polarized light from colloidal quantum dots (QDs) coupled with magnetically aligned segmented Au/Ni/Au nanowires (NWs). Optical characterizations reveal that the optimized QD-NW coupled structures emit highly polarized light with an s-to p-polarization (s/p) contrast as high as 15:1 corresponding to a degree of polarization of 0.88. These experimental results are supported by the finite-difference time-domain simulations, which demonstrate the interplay between the inter-NW distance and the degree of polarization.

  15. Understanding polarization properties of InAs quantum dots by atomistic modeling of growth dynamics

    SciTech Connect (OSTI)

    Tasco, Vittorianna; Todaro, Maria Teresa; De Giorgi, Milena; Passaseo, Adriana; Usman, Muhammad

    2013-12-04

    A model for realistic InAs quantum dot composition profile is proposed and analyzed, consisting of a double region scheme with an In-rich internal core and an In-poor external shell, in order to mimic the atomic scale phenomena such as In-Ga intermixing and In segregation during the growth and overgrowth with GaAs. The parameters of the proposed model are derived by reproducing the experimentally measured polarization data. Further understanding is developed by analyzing the strain fields which suggests that the two-composition model indeed results in lower strain energies than the commonly applied uniform composition model.

  16. Kondo time scales for quantum dots: Response to pulsed bias potentials

    SciTech Connect (OSTI)

    Plihal, Martin; Langreth, David C.; Nordlander, Peter

    2000-05-15

    The response of a quantum dot in the Kondo regime to rectangular pulsed bias potentials of various strengths and durations is studied theoretically. It is found that the rise time is faster than the fall time, and also faster than time scales normally associated with the Kondo problem. For larger values of the pulsed bias, one can induce dramatic oscillations in the induced current with a frequency approximating the splitting between the Kondo peaks that would be present in steady state. The effect persists in the total charge transported per pulse, which should facilitate the experimental observation of the phenomenon. (c) 2000 The American Physical Society.

  17. Secondary treatment of films of colloidal quantum dots for optoelectronics and devices produced thereby

    DOE Patents [OSTI]

    Semonin, Octavi Escala; Luther, Joseph M; Beard, Matthew C; Chen, Hsiang-Yu

    2014-04-01

    A method of forming an optoelectronic device. The method includes providing a deposition surface and contacting the deposition surface with a ligand exchange chemical and contacting the deposition surface with a quantum dot (QD) colloid. This initial process is repeated over one or more cycles to form an initial QD film on the deposition surface. The method further includes subsequently contacting the QD film with a secondary treatment chemical and optionally contacting the surface with additional QDs to form an enhanced QD layer exhibiting multiple exciton generation (MEG) upon absorption of high energy photons by the QD active layer. Devices having an enhanced QD active layer as described above are also disclosed.

  18. Determination of the Exciton Binding Energy in CdSe Quantum Dots

    SciTech Connect (OSTI)

    Meulenberg, R; Lee, J; Wolcott, A; Zhang, J; Terminello, L; van Buuren, T

    2009-10-27

    The exciton binding energy (EBE) in CdSe quantum dots (QDs) has been determined using x-ray spectroscopy. Using x-ray absorption and photoemission spectroscopy, the conduction band (CB) and valence band (VB) edge shifts as a function of particle size have been determined and combined to obtain the true band gap of the QDs (i.e. without and exciton). These values can be compared to the excitonic gap obtained using optical spectroscopy to determine the EBE. The experimental EBE results are compared with theoretical calculations on the EBE and show excellent agreement.

  19. An oleic acid-capped CdSe quantum-dot sensitized solar cell

    SciTech Connect (OSTI)

    Chen Jing; Song, J. L.; Deng, W. Q.; Sun, X. W.; Jiang, C. Y.; Lei, W.; Huang, J. H.; Liu, R. S.

    2009-04-13

    In this letter, we report an oleic acid (OA)-capped CdSe quantum-dot sensitized solar cell (QDSSC) with an improved performance. The TiO{sub 2}/OA-CdSe photoanode in a two-electrode device exhibited a photon-to-current conversion efficiency of 17.5% at 400 nm. At AM1.5G irradiation with 100 mW/cm{sup 2} light intensity, the QDSSCs based on OA-capped CdSe showed a power conversion efficiency of about 1%. The function of OA was to increase QD loading, extend the absorption range and possibly suppress the surface recombination.

  20. Dissipative soliton dynamics in a discrete magnetic nano-dot chain

    SciTech Connect (OSTI)

    Lee, Kyeong-Dong; You, Chun-Yeol; Song, Hyon-Seok; Shin, Sung-Chul; Park, Byong-Guk

    2014-02-03

    Soliton dynamics is studied in a discrete magnetic nano-dot chain by means of micromagnetic simulations together with an analytic model equation. A soliton under a dissipative system is driven by an applied field. The field-driven dissipative soliton enhances its mobility nonlinearly, as the characteristic frequency and the intrinsic Gilbert damping decrease. During the propagation, the soliton emits spin waves which act as an extrinsic damping channel. The characteristic frequency, the maximum velocity, and the localization length of the soliton are found to be proportional to the threshold field, the threshold velocity, and the initial mobility, respectively.