Photo-induced current spectroscopy study on semi-insulating LEC GaAs

Abstract

Semi-insulating GaAs grown by the liquid-encapsulated Czochralski (LEC) method was investigated by means of photo-induced current transient spectroscopy (PICTS). Surface and bulk contributions in the PICTS signal are compared by studying sandwich and planar samples. It is shown that, when using PICTS on materials with a depletion region, it is possible to identify the nature of traps. The used criterion is discussed. In addition the effects of the excitation light wavelength upon positive and negative bias PICTS spectra are reported.