Analysis of luminescence spectra of rectangular and trapezoidal InGaN/GaN multiple quantum wells under varying bias conditions

Abstract We report and analyze luminescence spectra for rectangular and trapezoidal InGaN/GaN multiple quantum wells (MQWs) under various bias voltages using well-calibrated numerical simulations. The effect of carrier localization due to clustering of In atoms in In-rich regions is taken into account by considering quantum dot-like structure in the QW for In contents exceeding 30%. The shape of the luminescence spectra obtained from different MQWs is explained physically on the basis of energy band diagram, electric field in the well and shift of the peak of electron and hole concentrations. Our findings demonstrate that under various bias conditions the trapezoidal MQWs produce luminescence peaks at the same wavelength whereas the rectangular MQWs do not. Such a striking feature associated with the trapezoidal MQWs may be exploited for color-stable photonic applications in which varying bias conditions modulate the light intensity while maintaining the peak emission at a constant wavelength.