Surface photovoltage effect and its time dependence in GaAs-GaAsP superlattice studied with combination of synchrotron and laser radiation

The surface photovoltage (SPV) effect and its temporal profiles in a GaAs-GaAsP superlattice (SL) were measured by core-level photoelectron spectroscopy with the combination of synchrotron radiation and laser. It was found that the SPV effect in the SL is remarkably suppressed as compared with that in a bulk GaAs. The difference in the temporal profile of the SPV between SL and bulk samples was observed in microsecond range. The suppression of the SPV effect in the negative electron affinity surfaces of the SL was also observed. It is concluded that the SL with a high-doping surface layer is suitable for the spin-polarized electron source without the SPV effect. (C) 2004 American Institute of Physics.