Investigation of the cesium activation of Ga⁢N photocathodes by low-energy electron microscopy

Sauty, Mylène; Johnson, Cameron W.; Tak, Tanay; Ho, Wan Ying; Chow, Yi Chao; Speck, James S.; Schmid, Andreas K.; Weisbuch, Claude; Peretti, Jacques

doi:10.1103/physrevapplied.22.034005

Title: Investigation of the cesium activation of Ga⁢N photocathodes by low-energy electron microscopy

Journal Article · Tue Sep 03 00:00:00 UTC 2024 · Physical Review Applied

DOI: https://doi.org/10.1103/physrevapplied.22.034005 · OSTI ID:2504270

^[1]; Johnson, Cameron W. ^[2];

^[3]; Ho, Wan Ying ^[3];

^[3]; Speck, James S. ^[3]; Schmid, Andreas K. ^[2];

^[4]; Peretti, Jacques ^[1]

Ecole Polytechnique, Palaiseau (France)
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Univ. of California, Santa Barbara, CA (United States)
Ecole Polytechnique, Palaiseau (France); Univ. of California, Santa Barbara, CA (United States)

Low-energy electron microscopy (LEEM) was performed on p-Ga⁢N samples during in situ cesium deposition. LEEM images of electron reflectivity recorded as a function of the incident electron energy at different Cs coverages allowed to spatially resolve the evolution of the local work function (WF) during the activation process. While the average WF drops by more than 3 eV, the local WF remains quite uniform across the surface throughout the activation process. Maximum fluctuations of less than 0.2 eV were observed in the WF maps for Cs coverage of a fraction of a monolayer. These fluctuations are mainly related to the surface topography, in particular, to the atomic steps’ structure, which replicates the substrate miscut. Apart from these weak spatial fluctuations, no Cs clusters that would induce strong local WF contrast were observed at the scale of the 20-nm resolution of the measurements. These observations agree with the simple model of semiconductor activation to negative electron affinity that describes the formation of a dipole layer as responsible for the lowering of the WF. Additionally, at complete Cs coverage, the WF becomes fully homogeneous over the surface, smoothing out features originating from defects and topography.

View Accepted Manuscript (DOE)

Cite

Export

Save

Research Organization:: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Univ. of California, Santa Barbara, CA (United States)

Sponsoring Organization:: USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)

Grant/Contract Number:: AC02-05CH11231; EE0009691

OSTI ID:: 2504270

Journal Information:: Physical Review Applied, Journal Name: Physical Review Applied Journal Issue: 3 Vol. 22; ISSN 2331-7019

Publisher:: American Physical Society (APS)Copyright Statement

Country of Publication:: United States

Language:: English

References (48)

Optical Investigation of Submonolayer Phase Transitions of Cs on GaAs(001) Paget, D. physica status solidi (a), Vol. 170, Issue 2 https://doi.org/10.1002/(SICI)1521-396X(199812)170:2<391::AID-PSSA391>3.0.CO;2-N	journal	December 1998
Negative affinity 3–5 photocathodes: Their physics and technology Spicer, W. E. Applied Physics, Vol. 12, Issue 2 https://doi.org/10.1007/BF00896137	journal	February 1977
Cesium, oxygen coadsorption on AlGaN(0001) surface: experimental research and ab initio calculations Yang, Mingzhu; Chang, Benkang; Wang, Meishan Journal of Materials Science: Materials in Electronics, Vol. 26, Issue 4 https://doi.org/10.1007/s10854-015-2665-4	journal	January 2015
GaAs-Cs: A new type of photoemitter Scheer, J. J.; van Laar, J. Solid State Communications, Vol. 3, Issue 8 https://doi.org/10.1016/0038-1098(65)90289-9	journal	August 1965
Work function and structural studies of alkali-covered semiconductors Weber, R. E.; Peria, W. T. Surface Science, Vol. 14, Issue 1 https://doi.org/10.1016/0039-6028(69)90043-0	journal	March 1969
On the interaction of cesium with cleaved GaAs(110) and Ge(111) surfaces: Work function measurements and adsorption site model Clemens, H. J.; Von Wienskowski, J.; Mönch, W. Surface Science, Vol. 78, Issue 3 https://doi.org/10.1016/0039-6028(78)90238-8	journal	December 1978
MOCVD growth of GaAs, AlGaAs and its application to transmission photocathodes Niigaki, Minoru; Nagai, Toshimitsu; Ota, Masashi Applied Surface Science, Vol. 33-34 https://doi.org/10.1016/0169-4332(88)90430-8	journal	September 1988
Electronic properties of cesium-covered GaN(0001) surfaces Kampen, Thorsten U.; Eyckeler, M.; Mönch, W. Applied Surface Science, Vol. 123-124 https://doi.org/10.1016/S0169-4332(97)00495-9	journal	January 1998
The photoemission characteristics of a NEA InGaN photocathode by simultaneously supplying Cs and O2 Kashima, Masahiro; Itokawa, Yuya; Kanai, Toshiya Applied Surface Science, Vol. 599 https://doi.org/10.1016/j.apsusc.2022.153882	journal	October 2022
Recent progress at SLAC extracting high charge from highly polarized photocathodes for future-collider applications Clendenin, J. E.; Brachmann, A.; Garwin, E. L. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 536, Issue 3 https://doi.org/10.1016/j.nima.2004.08.089	journal	January 2005
Cathode R&D for future light sources Dowell, D. H.; Bazarov, I.; Dunham, B. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 622, Issue 3 https://doi.org/10.1016/j.nima.2010.03.104	journal	October 2010
Insulator–metal phase transitions of alkali atoms on GaAs(001) Chiaradia, P.; Paget, D.; Tereshchenko, O. E. Surface Science, Vol. 600, Issue 2 https://doi.org/10.1016/j.susc.2005.10.036	journal	January 2006
Work function mapping of MoOx thin-films for application in electronic devices Cauduro, André L. F.; dos Reis, Roberto; Chen, Gong Ultramicroscopy, Vol. 183 https://doi.org/10.1016/j.ultramic.2017.03.025	journal	December 2017
Low-energy electron potentiometry Jobst, Johannes; Kautz, Jaap; Mytiliniou, Maria Ultramicroscopy, Vol. 181 https://doi.org/10.1016/j.ultramic.2017.05.015	journal	October 2017
Quantifying work function differences using low-energy electron microscopy: The case of mixed-terminated strontium titanate Jobst, Johannes; Boers, Laurens M.; Yin, Chunhai Ultramicroscopy, Vol. 200 https://doi.org/10.1016/j.ultramic.2019.02.018	journal	May 2019
Negative electron affinity of the GaN photocathode: a review on the basic theory, structure design, fabrication, and performance characterization. Wang, Xiaohui; Wang, Mengbo; Liao, Yulong Journal of Materials Chemistry C, Vol. 9, Issue 38 https://doi.org/10.1039/D1TC03244E	journal	January 2021
Review of photocathodes for electron beam sources in particle accelerators Schaber, Jana; Xiang, Rong; Gaponik, Nikolai Journal of Materials Chemistry C, Vol. 11, Issue 9 https://doi.org/10.1039/D2TC03729G	journal	January 2023
A compact electron‐spin‐polarization manipulator Duden, T.; Bauer, E. Review of Scientific Instruments, Vol. 66, Issue 4 https://doi.org/10.1063/1.1145569	journal	April 1995
Recent Polarized Photocathode R&D at SLAC Luh, D. -A. AIP Conference Proceedings https://doi.org/10.1063/1.1607290	conference	January 2003
GaN-based photocathodes with extremely high quantum efficiency Uchiyama, Shoichi; Takagi, Yasufumi; Niigaki, Minoru Applied Physics Letters, Vol. 86, Issue 10 https://doi.org/10.1063/1.1883707	journal	March 2005
Low energy electron microscopy and Auger electron spectroscopy studies of Cs-O activation layer on p-type GaAs photocathode Jin, Xiuguang; Cotta, Alexandre A. C.; Chen, Gong Journal of Applied Physics, Vol. 116, Issue 17 https://doi.org/10.1063/1.4901201	journal	November 2014
Quantitative correlation of hot electron emission to Auger recombination in the active region of c-plane blue III-N LEDs Ho, Wan Ying; Chow, Yi Chao; Myers, Daniel J. Applied Physics Letters, Vol. 119, Issue 5 https://doi.org/10.1063/5.0054636	journal	August 2021
Steady-state junction current distribution in p-n GaN diodes measured using low-energy electron microscopy (LEEM) Ho, Wan Ying; Johnson, Cameron W.; Tak, Tanay Applied Physics Letters, Vol. 123, Issue 3 https://doi.org/10.1063/5.0153947	journal	July 2023
Atomic layer etching (ALE) of III-nitrides Ho, Wan Ying; Chow, Yi Chao; Biegler, Zachary Applied Physics Letters, Vol. 123, Issue 6 https://doi.org/10.1063/5.0159048	journal	August 2023
Low energy electron microscopy Bauer, E. Reports on Progress in Physics, Vol. 57, Issue 9 https://doi.org/10.1088/0034-4885/57/9/002	journal	September 1994
Surface photovoltage in a p-GaN(Cs) photocathode Rozhkov, S. A.; Bakin, V. V.; Gorshkov, D. V. Journal of Physics: Conference Series, Vol. 1199 https://doi.org/10.1088/1742-6596/1199/1/012031	journal	March 2019
Photoemissive, Photoconductive, and Optical Absorption Studies of Alkali-Antimony Compounds Spicer, W. E. Physical Review, Vol. 112, Issue 1 https://doi.org/10.1103/PhysRev.112.114	journal	October 1958
Injection mechanisms in a III -nitride light-emitting diode as seen by self-emissive electron microscopy Tak, Tanay; Johnson, Cameron W.; Ho, Wan Ying Physical Review Applied, Vol. 20, Issue 6 https://doi.org/10.1103/PhysRevApplied.20.064045	journal	December 2023
Effects of Surface Nonuniformities on the Mean Transverse Energy from Photocathodes Karkare, Siddharth; Bazarov, Ivan Physical Review Applied, Vol. 4, Issue 2 https://doi.org/10.1103/PhysRevApplied.4.024015	journal	August 2015
Photoemission from activated gallium arsenide. I. Very-high-resolution energy distribution curves Drouhin, H. -J.; Hermann, C.; Lampel, G. Physical Review B, Vol. 31, Issue 6 https://doi.org/10.1103/PhysRevB.31.3859	journal	March 1985
Experimental photoemission results on the low-energy conduction bands of silicon Lassailly, Y.; Chiaradia, P.; Hermann, C. Physical Review B, Vol. 41, Issue 2 https://doi.org/10.1103/PhysRevB.41.1266	journal	January 1990
Band structure of indium phosphide from near-band-gap photoemission Peretti, J.; Drouhin, H. -J.; Paget, D. Physical Review B, Vol. 44, Issue 15 https://doi.org/10.1103/PhysRevB.44.7999	journal	October 1991
High-resolution energy analysis of field-assisted photoemission: A spectroscopic image of hot-electron transport in semiconductors Peretti, J.; Drouhin, H. -J.; Paget, D. Physical Review B, Vol. 47, Issue 7 https://doi.org/10.1103/PhysRevB.47.3603	journal	February 1993
Metallicity and disorder at the alkali-metal/GaAs(001) interface Tereshchenko, O. E.; Daineka, D. V.; Paget, D. Physical Review B, Vol. 64, Issue 8 https://doi.org/10.1103/PhysRevB.64.085310	journal	August 2001
Determination of the first satellite valley energy in the conduction band of wurtzite GaN by near-band-gap photoemission spectroscopy Piccardo, Marco; Martinelli, Lucio; Iveland, Justin Physical Review B, Vol. 89, Issue 23 https://doi.org/10.1103/PhysRevB.89.235124	journal	June 2014
Direct Measurement of Auger Electrons Emitted from a Semiconductor Light-Emitting Diode under Electrical Injection: Identification of the Dominant Mechanism for Efficiency Droop Iveland, Justin; Martinelli, Lucio; Peretti, Jacques Physical Review Letters, Vol. 110, Issue 17 https://doi.org/10.1103/PhysRevLett.110.177406	journal	April 2013
Localization Effect in Photoelectron Transport Induced by Alloy Disorder in Nitride Semiconductor Compounds Sauty, Mylène; Lopes, Nicolas M. S.; Banon, Jean-Philippe Physical Review Letters, Vol. 129, Issue 21 https://doi.org/10.1103/PhysRevLett.129.216602	journal	November 2022
Geometric and electronic properties of Cs structures on III-V (110) surfaces: From 1D and 2D insulators to 3D metals Whitman, L. J.; Stroscio, Joseph A.; Dragoset, R. A. Physical Review Letters, Vol. 66, Issue 10 https://doi.org/10.1103/PhysRevLett.66.1338	journal	March 1991
Prospect for high brightness III–nitride electron emitter Machuca, Francisco; Sun, Y.; Liu, Z. Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, Vol. 18, Issue 6 https://doi.org/10.1116/1.1321270	journal	January 2000
Photoemission lifetime of a negative electron affinity gallium nitride photocathode Nishitani, Tomohiro; Tabuchi, Masao; Amano, Hiroshi Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, Vol. 32, Issue 6 https://doi.org/10.1116/1.4901566	journal	November 2014
Preparation of Ga-terminated negative electron affinity-GaAs (100) surface by HCl-isopropanol treatment for nanoanalysis by scanning tunneling microscopy Fukuzoe, Ryutaro; Hirao, Masayuki; Yamanaka, Daichi Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, Vol. 36, Issue 6 https://doi.org/10.1116/1.5048060	journal	October 2018
Formation of the Cs/GaAs(001) interface: Work function, cesium sticking coefficient, and surface optical anisotropy Kierren, B.; Paget, D. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, Vol. 15, Issue 4 https://doi.org/10.1116/1.580611	journal	July 1997
Photocathode electron beam sources using GaN and InGaN with NEA surface Nishitani, T.; Maekawa, T.; Tabuchi, M. SPIE OPTO, SPIE Proceedings https://doi.org/10.1117/12.2076681	conference	March 2015
Development of a high-sensitivity UV photocathode using GaN film that works in transmission mode Ishigami, Yoshihiro; Akiyama, Keisuke; Nagata, Takaaki SPIE Proceedings https://doi.org/10.1117/12.918396	conference	May 2012
Energy distributions of photoelectrons emitted from p-GaN(Cs, O) with effective negative electron affinity Pakhnevich, A. A.; Bakin, V. V.; Yaz’kov, A. V. Journal of Experimental and Theoretical Physics Letters, Vol. 79, Issue 10 https://doi.org/10.1134/1.1780556	journal	May 2004
Emission of ballistic photoelectrons from p-GaN(Cs,O) with the effective negative electron affinity Pakhnevich, A. A.; Bakin, V. V.; Shaĭbler, G. É. Physics of the Solid State, Vol. 49, Issue 11 https://doi.org/10.1134/S1063783407110091	journal	November 2007
STM Study on Adsorption Structures of Cs on the As-Terminated GaAs(001) (2×4) Surface by Alternating Supply of Cs and O₂ Hirao, Masayuki; Yamanaka, Daichi; Yazaki, Takanori IEICE Transactions on Electronics, Vol. E99.C, Issue 3 https://doi.org/10.1587/transele.E99.C.376	journal	January 2016
Review of night vision technology Chrzanowski, K. Opto-Electronics Review, Vol. 21, Issue 2 https://doi.org/10.2478/s11772-013-0089-3	journal	January 2013

Similar Records

Injection mechanisms in a III-nitride light-emitting diode as seen by self-emissive electron microscopy

Journal Article · Tue Dec 26 00:00:00 UTC 2023 · Physical Review Applied · OSTI ID:2505094

Tak, Tanay; Johnson, Cameron W.; Ho, Wan Ying; +8 more

A Perturbative Solution for Nonlinear Stratified Upwelling over a Frictional Slope

Journal Article · Sun Oct 01 04:00:00 UTC 2023 · Journal of Physical Oceanography · OSTI ID:2580152

Choi, Jang-Geun; Pringle, James; Lippmann, Thomas

Influence of Exposure to Multiple Brazing Cycles on the Integrity of OFE Copper Brazed Joints

Journal Article · Wed Nov 15 04:00:00 UTC 2017 · Journal of Materials Engineering and Performance · OSTI ID:22860784

Sandha, R. S.; Choudhary, R. S.; Nagpure, D. C.; +4 more

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
III-V semiconductors
adsorption
alkali metals
electron affinity
electron emission
growth
low-energy electron microscopy
nucleation on surfaces

Title: Investigation of the cesium activation of Ga⁢N photocathodes by low-energy electron microscopy

Citation Formats

References (48)

Similar Records

Related Subjects