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Effects of metal ion chemisorption on gallium arsenide surface recombination: picosecond luminescence decay measurements

Ryba, Gail N. and Kenyon, C. N. and Lewis, Nathan S. (1993) Effects of metal ion chemisorption on gallium arsenide surface recombination: picosecond luminescence decay measurements. Journal of Physical Chemistry, 97 (51). pp. 13814-13819. ISSN 0022-3654. doi:10.1021/j100153a062.

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n-GaAs/KOHSe^(-/2-)(aq) contacts have been studied using real time photoluminescence decay techniques. This system is of interest because metal ion chemisorption improves the steady-state current-voltage properties of GaAs/KOH-Se^(-/2-)(aq)/Pt cells, yielding 16% efficiency under simulated 1-sun illumination conditions. In this work, the luminescence decay dynamics of thin epilayer GaAs samples under high level injection conditions were monitored in contact with KOHSe^(-/2-)(aq) solutions. The photoluminescence signals decayed more rapidly after metal ion chemisorption than after a fresh etch, indicating that the metal ion treatment induced a more active recombination and/or charge-transfer process than the etch. A finite-difference simulation was used to model the decays and to extract a minority carrier surface recombination velocity, S_(min), for these systems. For etched GaAs surfaces, S_(min) = 5 X 10^3 cm s^(-1), while GaAs surfaces that had been etched and then exposed to 0.010 M Co(NH_3)_6^(3+) (pH = 11) solutions displayed S_(min) = 2 X 10^5 cm s^(-1). Qualitatively similar behavior was observed for Rh-, Ru-, and Os-treated GaAs surfaces as well. These data are fully consistent with prior suggestions that the primary effect of metal ion chemisorption is to increase the rate of hole transfer to the Se^(-/2-)(aq) electrolyte, as opposed to decreasing surface recombination processes at the GaAs/liquid contact.

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Lewis, Nathan S.0000-0001-5245-0538
Alternate Title:Effects of metal ion chemisorption on GaAs surface recombination: picosecond luminescence decay measurements
Additional Information:© 1993 American Chemical Society. Received: September 1, 1993. We gratefully acknowledge C. L. R. Lewis, H. MacMillan, L. Eng, and A. Yariv for supplying the GaAs samples that were used in this work. We are also grateful to Steve Feldberg for discussions regarding the finite-difference calculations, to J. Winkler of Caltech and J. Perry of JPL for invaluable assistance with the laser experiments, and to A. Heller of the University of Texas, Austin, for helpful discussions. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, through the Fundamental Interactions Branch.
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Department of Energy (DOE)UNSPECIFIED
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Division of Chemistry and Chemical Engineering8853
Issue or Number:51
Record Number:CaltechAUTHORS:20180601-145807055
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Official Citation:Effects of metal ion chemisorption on gallium arsenide surface recombination: picosecond luminescence decay measurements Gail N. Ryba, C. N. Kenyon, and Nathan S. Lewis The Journal of Physical Chemistry 1993 97 (51), 13814-13819 DOI: 10.1021/j100153a062
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:86755
Deposited By: George Porter
Deposited On:01 Jun 2018 22:49
Last Modified:15 Nov 2021 20:41

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