Determination of energy band and surface-state locations in GaAs using the separated-medium surface-acoustoelectric effect

Abstract
The wavelength dependence of the peak transverse acoustoelectric voltage and the surface acoustic wave attenuation determine the energy band and the locations of the surface states in the energy gap of GaAs. The dependence is explained by direct optical transition between the bands and optical transition from surface states. This method needs no contacts to the semiconductor surface, is simple, very sensitive, and accurate.