Chemical modification of n-GaAs photoanodes with group VIIIB metal ions: Stability in contact with 1. 0 M KOH(aq)-0. 10 M K[sub 2]Se(aq) solutions and I-V properties in contact with 1. 0 M KOH(aq)-0. 3 M K[sub 2]Te(aq) electrolytes

Journal Article · Thu Nov 28 04:00:00 EST 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100177a092· OSTI ID:6923567

Tan, M X; Newcomb, C; Kumar, A; Lunt, S R; Sailor, M J; Tufts, B J; Lewis, N S ^[1]

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1. California Inst. of Tech., Pasadena (United States)

A quantitative study has been performed on the stability of GaAs surfaces to photoanodic corrosion in contact with the 1.0 M KOH(aq)-0.10 M K[sub 2]Se(aq)-0.01 M K[sub 2]Se[sub 2](aq) electrolyte. In this electrolyte, chemically etched n-type GaAs electrodes displayed significant photocorrosion in competition with faradaic charge transfer to Se[sup 2[minus]](aq). Chemisorption of group VIIIB metal ions, including complexes of Co(III), Os(III), and Ru(III), onto the etched GaAs surface yielded improved current-voltage (I-V) behavior of the GaAs photoanode and also resulted in a significant reduction in photocorrosion. This behavior implies that the chemisorbed metal ions act to increase the rate of hole transfer to the Se[sup 2[minus]] donor species, as opposed to the passivation of nonradiative surface recombination. Related experiments on n-GaAs photoanodes in contact with the 1.0 M KOH(aq)-0.3 M Te[sup 2[minus]](aq)-0.01 M Te[sub 2][sup 2[minus]](aq) electrolyte have also been performed. The I-V properties of n-GaAs, p-GaAs, and Sn-doped In[sub 2]O[sub 3] electrodes have been investigated in this electrolyte, and these measurements have been used to elucidate common mechanistic features of charge-transfer reactions for the Se[sup 2[minus]](aq) and Te[sup 2[minus]](aq) redox systems.

• OSTI ID: 6923567
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:24; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400* -- Electrochemistry
ALKALI METAL COMPOUNDS
ANIONS
ANODES
ARSENIC COMPOUNDS
ARSENIDES
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMISORPTION
CHEMISTRY
COBALT COMPLEXES
COMPLEXES
CORROSION
DATA
ELECTRODES
ELECTROLYTES
EXPERIMENTAL DATA
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
HYDROGEN COMPOUNDS
HYDROXIDES
INFORMATION
IONS
NUMERICAL DATA
OSMIUM COMPLEXES
OXYGEN COMPOUNDS
PHOTOANODES
PHOTOCHEMISTRY
PNICTIDES
POTASSIUM COMPOUNDS
POTASSIUM HYDROXIDES
POTASSIUM SELENIDES
POTASSIUM TELLURIDES
RUTHENIUM COMPLEXES
SELENIDES
SELENIUM COMPOUNDS
SEPARATION PROCESSES
SORPTION
STABILITY
TELLURIDES
TELLURIUM COMPOUNDS
TRANSITION ELEMENT COMPLEXES