Electric field effect on the emission of electron-irradiation-induced defects in n-GaAs

The enhancement of the emission rate of electron-irradiation-induced defects in the presence of an electric field in n-type GaAs with carrier concentrations ranging from 1 × 1014 to 1 × 1016 cm-3 has been investigated using deep level transient spectroscopy (DLTS). The relationship between the electric field strength and the emission rate of the three major electron traps (E1, E2 and E3) in electron-irradiated n-type GaAs materials is presented. Using the models for phonon-assisted tunnel emission of electrons from deep levels developed by Pons et al. and the enhancement due to Poole-Frenkel potential barrier lowering a correlation was attempted between the experimental results and those predicted by the above-mentioned two models. From these results an estimate of the Franck-Condon shift for the three defects is presented.