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Title: Semiconductor electrodes. 24. Behavior and photoelectrochemical cells based on p-type GaAs in aqueous solutions

Journal Article · · J. Am. Chem. Soc.; (United States)
DOI:https://doi.org/10.1021/ja00531a002· OSTI ID:5140957

The electrochemical behavior of single-crystal p-type GaAs in aqueous solutions containing several redox couples (I/sub 3//sup -//I/sup -/,Fe(III)/Fe(II),SN(IV)/Sn(II),Eu(III)/Eu(II)) in the dark and under irradiation is described. The observation that the difference in potential between that for the onset of photocurrent and the standard potential for the redox couple was 0.4-0.5V, independent of the couple, leads to a revised model for semiconductor/electrolyte solution interface with semiconductors having a high density of surface states with energies within the band-gap region. In such a surface controlled system the Fermi level of the semiconductor is pinned at the surface state level. Several solar cells in which p-GaAs shows stable behavior are described. The cell p-GaAs/I/sub 3//sup -/(0.25 M),I/sup -/(0.75 M)/Pt showed an open-circuit voltage of 0.20 V and a short-circuit current density of 30 mA/cm/sup 2/ under irradiation with 1.7-mW He-Ne laser. The quantum efficiency at the maximum photocurrent in this cell was about 95%.

Research Organization:
Univ. of Texas, Austin
OSTI ID:
5140957
Journal Information:
J. Am. Chem. Soc.; (United States), Vol. 102:11
Country of Publication:
United States
Language:
English