Theoretical study of the temperature dependence of Auger-Meitner recombination in (Al,Ga)N quantum wells.

Abstract

Non-radiative Auger-Meitner recombination processes in III-nitride based optoelectronic devices operating in thevisiblespectral range have received significant attention in recent years as they can present a major contribution to the efficiency drop at high temperatures and carrier densities. However, insight into these recombination processes is sparse for III-N devices operating in theultravioletwavelength window. In this work we target the temperature dependence of the Auger-Meitner recombination rate in (Al,Ga)N/AlN quantum wells by means of an atomistic electronic structure model that accounts for random alloy fluctuations and connected carrier localisation effects. Our calculations show that in the low temperature regime both the non-radiative Auger-Meitner and radiative recombination rate are strongly impacted by alloy disorder induced carrier localisation effects in these systems. The influence of alloy disorder on the recombination rates is reduced in the high temperature regime, especially for the radiative rate. The Auger-Meitner recombination rate, however, may still be more strongly impacted by alloy disorder when compared to the radiative rate. Our calculations show that while on average radiative recombination slightly increases with increasing temperature, the Auger-Meitner recombination process may, on average, slightly decrease in the temperature range relevant to the thermal efficiency drop (thermal droop). This finding suggests that the considered Auger-Meitner recombination process is unlikely to be directly responsible for the thermal efficiency drop observed experimentally in (Al,Ga)N/AlN quantum well based light emitting devices. Thus, different non-radiative processes, external to the active region, may be the underlying cause of thermal droop in (Al,Ga)N wells.