Observation of minority-carrier traps in InGaN∕GaN multiple-quantum-well light-emitting diodes during deep-level transient spectroscopy measurements

Abstract

An unusual appearance of a peak in the deep-level transient spectroscopy (DLTS) data for minority-carrier traps from an InGaN∕GaN multiple-quantum-well (MQW) light-emitting diode, under a bias condition provided by a square pulse of varying height superimposed over the reverse-bias voltage, is newly observed and analyzed. The peak is attributed to hole traps, having the estimated activation energy of 0.7eV, in the last one (toward the p side) among the GaN barrier layers in the MQW structure. We have found that the ΔC∕Cr-versus temperature pattern from the DLTS measurement agrees well with the pattern predicted from the model of hole traps, i.e., the minority-carrier traps, in the MQW barrier layer, whose occupation probability is governed by the local hole quasi-Fermi level.