Vacuum Related Cr Level in Gallium Arsenide Application of Optical Deep Level Transient Spectroscopy

Abstract

Short duration electrical pulses in Deep Level Transient Spectroscopy (DLTS) are normally used to study the majority and minority carrier trApplng levels in semiconductors by charging and then recording the capacitance of a p-n junction diode as a function of time as the level discharges. Similar techniques can be applied to investigate majority carrier traps only using Schottky barrier diodes but not the minority carrier traps. It has been demonstrated that both majority and minority carrier traps can be characterized using optical excitation on Schottky barrier diodes in DLTS, referred here as Optical DLTS (ODLTS). The Cr acceptor level in GaAs has been studied by ODLTS and is found to have an energy of 0.81 eV above the valence band edge with a capture cross section of 2.5 10−16cm2. The energy of this level with respect to the vacuum level is found to be almost the same irrespective of the particular compound ei GaAs, InP and GaP, opening the possibility of determining the valence and conduction band o...