Photoelectrochemical characterization of GaAs and doped Fe/sub 2/O/sub 3/ semiconductive electrodes

The characterization for semiconductive electrodes of GaAs and Fe/sub 2/O/sub 3/ doped with MgO or CaO was investigated. The doped Fe/sub 2/O/sub 3/ semiconductive electrodes were prepared from thin films sintered at temperatures from 1100 to 1450/spl deg/C, and rapidly quenched in distilled water. The surfaces of the electrodes containing both corundum structure Fe/sub 2/O/sub 3/ and spinel structure Mg/sub x/Fe/sub 3-x/O/sub 4/ or Ca/sub x/Fe/sub 3-x/O/sub 4/ were analyzed by X-ray diffraction. The critical anodic and cathodic photocurrents on these electrodes were obtained at a doping amount of 5/spl sim/11 wt%. When the GaAs electrodes were treated with methylene violet, the anodic photocurrents were temporarily enhanced and inverted to the cathodic photocurrents after the treated surface was dried.