Photorefractive characterization of deep level compensation in semi-insulating GaAs

Abstract
We show that photorefractive beam coupling can be used for deep level spectroscopy in semi-insulating GaAs. In four samples cut from different locations in a single boule of GaAs, we find the same degree of compensation as determined from absorption spectra, Hall measurements, and the photorefractive effect. In the most compensated of our samples, the sign of the photorefractive beam coupling changes from electron to hole dominated as the optical wavelength is changed from 1.06 to 1.15 μm. Furthermore, we show that absorption spectra for semi-insulating GaAs can be used to choose samples for optimal photorefractive behavior at wavelengths of 0.9–1.5 μm.