Distinguishing between buried semiconductor/metal contacts and hybrid semiconductor/metal/liquid contacts at n-gallium arsenide/potassium hydroxide-selenium (Se^(-/2-))(aq) junctions
Abstract
The current-voltage properties of n-GaAs photoanodes have been evaluated in KOH-Se^(-/2-)(aq), CH3CN-Fc^(+/0), and CH₃CN-MV^(2+/+) solutions. Chemisorption of transition-metal ions (Rhᴵᴵᴵ, Coᴵᴵᴵ, Ruᴵᴵᴵ, Osᴵᴵᴵ) onto n-GaAs has been shown previously to effect improved photoanode behavior for n-GaAs/KOH-Se^(-/2-)(aq) contacts, but it is not clear whether the chemisorbed metal forms a buried semiconductor/metal junction or results in a hybrid semiconductor/metal/liquid contact. After chemisorption of transition-metal ions, n-GaAs photoanodes displayed different open circuit voltages in contact with each electrolyte solution investigated. The role of the chemisorbed metal in the n-GaAs/M/KOH-Se^(-/2-)(aq) system is, therefore, best described as catalyzing interfacial charge transfer at the semiconductor/liquid interface, as opposed to establishing a semiconductor/metal or semiconductor/insulator/metal contact that is exposed to, but not influenced by, the electrolyte solution.
Additional Information
© 1993 American Chemical Society. We thank the Department of Energy, Office of Basic Energy Sciences, for their generous support of this work. We acknowledge stimulating discussions with Prof. R. Memming and thank S. Halsell of Caltech for assistance with the electrode photographs. We also are grateful to Dr. A. J. Nozik of NREL for forwarding a preprint of time-resolved studies of GaAs/liquid contacts.Additional details
Identifiers
- Eprint ID
- 121033
- Resolver ID
- CaltechAUTHORS:20230419-953364000.24
Funding
- Department of Energy (DOE)
Dates
- Created
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2023-04-26Created from EPrint's datestamp field
- Updated
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2023-04-26Created from EPrint's last_modified field
Caltech Custom Metadata
- Other Numbering System Name
- Caltech Division of Chemistry and Chemical Engineering
- Other Numbering System Identifier
- 8793