Semiconductor Electrodes: XI . Behavior of n‐ and p‐Type Single Crystal Semconductors Covered with Thin Films

Abstract

Single crystal semiconductors (n-Si, p-Si, n-GaAs, p-GaAs, n-GaP, n-In.P, and n-CdS) were coated with n-type TiO~ by a chemical vapor deposition technique, and the electron and hole transfer properties across the heterojunc-tion so produced were investigated. The quality of the deposited TiO~ film de-pended upon several factors including temperature and substrate material. When high quality crack-free TiO2 coats were obtained on n-type substrates, the substrate was stabilized with no dissolution during the photo-oxidation of water. However, the oxidation was due o~y to the photoexcitation of the TiO~, and any holes produced in the substrate were not transferred through the TiO~ to the solution. The use of p-type substrates coated with TiO2 as photocathodes was limited by band-bending requirements at the p-n hetero-junction and the TiO~-solution interface. The utilization of small bandgap (E s) semiconductor