Dynamics of surface photovoltage effects on clean and negative electron affinity surfaces of p-GaAs (100)

Core-level photoelectron spectroscopy with the combination of synchrotron radiation and laser light was used for exploring the dynamics of the surface photovoltage (SPV) effect on a p-GaAs (100). It was found that a temporal profile of the SPV is very different in microsecond range between room temperature and 90 K. The results can be explained with the recombination of photoexcited carriers via thermionic and tunneling processes. The SPV effects and its temporal profiles on the negative electron-affinity (NEA) surface were also studied. It was observed that the SPV effect is suppressed on the NEA surface, which may be due to the escape process of the photoexcited carriers. (author)