Relaxational kinetics of photoemission and photon-enhanced thermionic emission from p-GaAs surface with nonequilibrium Cs overlayers

摘要

Photoreflectance and photoemission quantum yield spectroscopies are used for the experimental study of direct photoemission, photon-enhanced thermionic emission (PETE), surface band bending and photovoltage, effective electron affinity, and probabilities of electron escape into a vacuum under cesium deposition on the Ga-richp-GaAs(0 0 1) surface and the subsequent structural relaxation in the absorbed overlayer. The relaxational decrease of the direct photoemission and PETE at small Cs coverages is caused by the band bending decrease, while the photocurrent relaxational increase at large coverages is due to electron affinity relaxation.