ELECTRON TRANSFER REACTIONS AT n-GaP (100) and (111) IN ACETONITRILE SOLUTIONS FACILITATED BY CATION ADSORPTION.

Article abstract of DOI:10.1002/bbpc.19840881009

Electron transfer reactions occurring at n-GaP (111) and (100) electrodes have been investigated in acetonitrile solutions. In the presence of strongly oxidizing cations, such as 10-methylphenothiazine (10-MP** plus ** multiplied by (times) ), Ferrocene (Cp//2Fe** plus ) and tetrathiafulvalen (TTF** plus ** multiplied by (times) ), it is shown that electron transfer proceeds directly from the conduction band to cations adsorbed at the semiconductor surface. Differential capacitance and photo/dark-current measurements have been used to identify a considerable positive shift of the flatband potential (U//F//B) in the presence of the oxidizing cation. This phenomenon is absent in the presence of a similarly oxidizing neutral species. No evidence was obtained to support the model which proposes mediated electron transfer via surface states deep in the band gap.