ELECTROREFLECTANCE AND SEMICONDUCTOR SURFACE

Periodic modulation of the potential barrier inside the reflecting surface of a semiconductor results in a synchronous modulation of the reflectance. This electroreflectance effect is a function of the surface potential and can therefore be used as a reference property. Calibration of this reference against surface conductance or surface capacity in the field-effect or electrolytic version of the method, respectively, establishes the functional relationship and suggests surface investigations by strictly optical means. Quantitative interpretation of electroreflectance spectra in band structure analysis requires control over the potential distribution in the various space-charge regions. In the electrolytic method, strict conditions for polarization and modulation must be satisfied to make line-shape discussions of electro-reflectance spectra meaningful. © 1969.