Radiation damage by high energy electrons in GaAs: A DLTS (deep level transient spectroscopy) examination

An isothermal variation of the DLTS (Deep Level Transient Spectroscopy) technique is developed and applied to the study of displacement damage in GaAs, through the determination of threshold energies and displacement cross sections. Results correspond to those of a light emitting diode based method. A pronounced anisotropy is found for the threshold energy. A linearly increasing displacement probability function is shown to model the displacement cross section in 100 angular brackets direction, as compared with the 111 angular brackets direction, which requires only a single step function. Differences in the damage between these two directions are as large as a factor of two.