Electrical Characterization Of Nitrogen Acceptors In p-ZnSe/p-GaAs Grown By Molecular Beam Epitaxy

Abstract

AbstractUsing current-voltage measurements, deep-level transient spectroscopy and admittance spectroscopy we investigated nitrogen doped ZnSe grown on p-GaAs substrates by molecular beam epitaxy. Three major hole traps were observed with energy levels at 0. 11, 0.46, and 0.56 eV from the valence band. We attribute the level at 0.11 eV to a nitrogen acceptor. No other direct observations of this important acceptor level in p-ZnSe have been reported in the literature so far. The two remaining levels may originate from the nitrogen doping process. In addition, reverse current-voltage characteristics of the ZnSe/GaAs heterojunction show a hysteresis at low temperature and a soft saturation. At a constant reverse bias the current increases slowly until it reaches a steady state value. This behavior is attributed to a slow voltage-induced barrier lowering due to the presence of mismatch interface states. Therefore, these analyses are of a major interest for applications of ZnSe/GaAs based devices and illustrates the necessity of improving the growth conditions of such structures.