Investigations on electron transfer processes at GaAs electrodes by impedance spectroscopy
- Institut f. Solarenergieforschung, Hannover (Germany)
According to basic theories on processes at semiconductor electrolyte interfaces current-potential curves representing a majority carrier transfer, are expected to have a slope of 60 mV per decade, provided that the externally applied voltage occurs entirely across the space charge region of the semiconductor. The latter condition is usually checked by dynamic Mott-Schottky measurements. These measurements are mostly performed in a potential range where no current occurs, i.e. they do not give any information on the potential distribution in the range where the current strongly increases with potential. On the other hand corresponding data can be obtained by impedance spectroscopy measurements. Considerably shifts of the flatband potential have been found which may have different origins. In addition, performing these measurements over a large frequency range, one can also obtain quantitative informations on the kinetics of very fast diffusion controlled reaction. Various redox. reaction at p-GaAs electrodes in aqueous and non-aqueous electrolytes and the hydrogen evolution at n-GaAs have been studied. Quantitative values of rate constants will given and reaction mechanisms will be discussed in terms of basic theories.
- OSTI ID:
- 370788
- Report Number(s):
- CONF-960376--
- Country of Publication:
- United States
- Language:
- English
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