Space-Charge-Limited Efficiency of Electrically-Injected Carriers Localization

Abstract

The mechanism for the influence of defects in theGaN on the efficiency of localization of electrically-injected charge carriers in the InGaN|GaN quantum well is studied using tunnel spectroscopy of deep centers. It is found that the curves of the quantum efficiency and the spectral efficiency of radiative recombination dependencies on forward bias have the shape with maximum and humps at the biases corresponding to the impurity bands of color centers in GaN. The quantum efficiency droop with increasing bias is accompanied by a blue shift of the emission spectrum. We explain these effects based on the model of carrier localization in the quantum well, which takes into account the significant contribution to the tunneling transparency of the potential walls of the quantum well from ionized deep centers and their recharging with increasing forward bias. Keywords: gallium nitride, quantum well, charge carrier localization, tunneling, quantum effeciency, color centers.