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Title: Independent tuning of work function and field enhancement factor in hybrid lanthanum hexaboride-graphene-silicon field emitters

Authors:
; ;  [1];  [2];  [3];  [4]; ; ; ; ;
  1. Department of Chemical Engineering and Material Science, University of Southern California, Los Angeles, California 90089
  2. Molecular Foundry, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720
  3. Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089
  4. Department of Chemistry and Center for Electron Microscopy and Microanalysis, University of Southern California, Los Angeles, California 90089
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1409864
Grant/Contract Number:
AC02-05CH11231
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Vacuum Science and Technology. B, Nanotechnology and Microelectronics
Additional Journal Information:
Journal Volume: 35; Journal Issue: 6; Related Information: CHORUS Timestamp: 2018-02-14 21:14:56; Journal ID: ISSN 2166-2746
Publisher:
American Vacuum Society
Country of Publication:
United States
Language:
English

Citation Formats

Rezaeifar, Fatemeh, Lin, Qingfeng, Chen, Xiangyu, Mattox, Tracy M., Garg, Ayush, Clough, Andrew, Poudel, Nirakar, Blankemeier, Louis, Sarkar, Debarghya, Cronin, Stephen B., and Kapadia, Rehan. Independent tuning of work function and field enhancement factor in hybrid lanthanum hexaboride-graphene-silicon field emitters. United States: N. p., 2017. Web. doi:10.1116/1.5001324.
Rezaeifar, Fatemeh, Lin, Qingfeng, Chen, Xiangyu, Mattox, Tracy M., Garg, Ayush, Clough, Andrew, Poudel, Nirakar, Blankemeier, Louis, Sarkar, Debarghya, Cronin, Stephen B., & Kapadia, Rehan. Independent tuning of work function and field enhancement factor in hybrid lanthanum hexaboride-graphene-silicon field emitters. United States. doi:10.1116/1.5001324.
Rezaeifar, Fatemeh, Lin, Qingfeng, Chen, Xiangyu, Mattox, Tracy M., Garg, Ayush, Clough, Andrew, Poudel, Nirakar, Blankemeier, Louis, Sarkar, Debarghya, Cronin, Stephen B., and Kapadia, Rehan. Wed . "Independent tuning of work function and field enhancement factor in hybrid lanthanum hexaboride-graphene-silicon field emitters". United States. doi:10.1116/1.5001324.
@article{osti_1409864,
title = {Independent tuning of work function and field enhancement factor in hybrid lanthanum hexaboride-graphene-silicon field emitters},
author = {Rezaeifar, Fatemeh and Lin, Qingfeng and Chen, Xiangyu and Mattox, Tracy M. and Garg, Ayush and Clough, Andrew and Poudel, Nirakar and Blankemeier, Louis and Sarkar, Debarghya and Cronin, Stephen B. and Kapadia, Rehan},
abstractNote = {},
doi = {10.1116/1.5001324},
journal = {Journal of Vacuum Science and Technology. B, Nanotechnology and Microelectronics},
number = 6,
volume = 35,
place = {United States},
year = {Wed Nov 01 00:00:00 EDT 2017},
month = {Wed Nov 01 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on November 22, 2018
Publisher's Accepted Manuscript

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  • A work function of 2.36 eV and a Richardson constant of 120 A/cm/sup 2/ K/sup 2/ have been measured for a hot-pressed porous lanthanum hexaboride rod cathode. It is shown that the LaB/sub 6/ work function is highly susceptible to poisoning by molybdenum deposited at high temperatures during experiments. A stable work function of about 2.7 eV is then measured. After removal of the molybdenum by atomic iodine flux, the work function of clean LaB/sub 6/ is restored.
  • Graphene layers grown by chemical vapor deposition were, respectively, irradiated for 0, 20, 40, and 60 min by an ultraviolet light source in order to experimentally study the change in the work function of graphene. The dependences of the work function and carrier concentration upon ultraviolet irradiation have been found. It is shown that ultraviolet irradiation may lead to oxygen desorption, thus reducing the hole density and work function of graphene. Based on the well-known expression for the Fermi energy of Dirac fermions, the Fermi velocity of graphene was extracted to be about 5.2 Multiplication-Sign 10{sup 5} m/s.
  • Graphene prepared by the chemical vapor deposition method was treated with nitrogen plasma under different radio-frequency (rf) power conditions in order to experimentally study the change in the work function. Control of the rf power could change the work function of graphene from 4.91 eV to 4.37 eV. It is shown that the increased rf power may lead to the increased number of graphitic nitrogen, increasing the electron concentration, and shifting the Fermi level to higher energy. The ability to controllably tune the work function of graphene is essential for optimizing the efficiency of optoelectronic and electronic devices.
  • Co-sputtered nickel silicide films were evaluated on thin layers of SiO{sub 2} gate dielectrics. Work function values ranging from 4.86 eV for Ni rich films to 4.3 eV were observed at 400 deg. C and were found to be a strong function of the Ni and Si ratio in the films. Phase analysis indicated the presence of different phases of Ni{sub x}Si{sub y} for varying concentrations of Ni and Si. High-temperature characteristics, leakage, and change in equivalent oxide thickness values were also evaluated for selected conditions. Rutherford backscattering, x-ray diffraction, Auger electron spectroscopy and high-resolution transmission electron microscopy were usedmore » for material analyses.« less
  • Field-emission and field-ion microscopy studies are carried out on (001) -oriented LaB/sub 6/ single-crystal tips. Surface states and some field-emission characteristics are examined. The facet of low-index planes, (001), )011), and )111), is observed after heating a tip at high temperatures. The field-emission current fluctuations from thermally cleaned LaB/sub 6/ tips are larger than those of W field emitters. Field-emission patterns are found to depend on the local curvatures of the tip surface. The surface states are discussed by considering the effects of surface diffusion and evaporation for LaB/sub 6/ during high-temperature heat treatment.