Ss. Kocha et Be. Liebert, CHARACTERIZATION OF SOME TERNARY III-V SEMICONDUCTOR ELECTROLYTE INTERFACES UTILIZING ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY, Electrochimica acta, 38(14), 1993, pp. 1993-1997
Single crystal GaInP2 and Ga1-xAlxAs-aqueous electrolyte interfaces we
re investigated utilizing electrochemical impedance spectroscopy. Both
materials have band gaps that are much larger than the theoretical fr
ee energy required to decompose water (1.23 eV) and may do so dependin
g on the energetic positions of the band edges. Impedance spectra (500
muHz-100 kHz) were used to model the interface in terms of a space-ch
arge layer capacitance, a constant phase element and oxide film capaci
tance in some cases, and associated resistances. The flat-band potenti
al and carrier concentrations were determined from Mott-Schottky plots
. It was found that the corresponding band edges of both materials fal
l short of encompassing both the hydrogen and oxygen redox levels and
are thus not capable of splitting water in the absence of an external
bias.