Photoeffects of a p-type GaAs coated with WO3 thin film have been investigated as a function of film thickness and photoresponse transients of the WO3/GaAs electrode were studied. Also, these results were compared to those for a single p-type GaAs electrode. The photocurrent of the WO3/GaAs electrode depended on the film thickness of the WO3, showing an optimum photon efficiency for specimens of 800 Å thickness. This is due to the existence of an effective interface state within the band gap which reduces trapping of carriers and facilitates earner movement. For an 800-Å-thick WO3 thin film deposited p-GaAs photoelectrode, the photogenerated electrons were found to move to an electrolyte at a higher positive onset potential compared with that of single p-type GaAs, which was confirmed as a result of transient behavior. I-V and C-V characteristics of the WO3/GaAs electrode were also compared with those of a single p-type GaAs electrode.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)