Method for in-situ determination of the fermi level in GaAs and similar materials by photoreflectance

摘要

A method for in-situ determination by photoreflectance of the Fermi level (VF) at the surfaces or interfaces of GaAs and related materials, in which a probe beam of monochromatic light and a modulated pump beam from a pump source are directed onto a sample, and the measured barrier height Vm=VF-VS is obtained from the information in the reflected light, where VS represents the surface voltage effects on the sample by the photoreflectance, whereby Vm approaches VF as VS approaches zero during repeated tests in which a parameter such as temperature affecting the numerical value of VS is changed until there is flattening of the curve illlustrating Vm as a function of the parameter.