Atomistic analysis of Auger recombination in c -plane (In,Ga)N/GaN quantum wells: Temperature-dependent competition between radiative and nonradiative recombination

We present an atomistic theoretical study of the temperature dependence of the competition between Auger and radiative recombination in c-plane (In,Ga)N/GaN quantum wells with indium (In) contents of 10%, 15%, and 25%. The model accounts for random alloy fluctuations and the connected fluctuations in strain and built-in field. Our investigations reveal that the total Auger recombination rate exhibits a weak temperature dependence; at a temperature of 300 K and a carrier density of n3D=3.8×1018cm-3, we find total Auger coefficients in the range of ≈6×10-30cm6/s (10% In) to ≈3×10-31cm6/s (25% In), thus large enough to significantly impact the efficiency in (In,Ga)N systems. Our calculations show that the hole-hole-electron Auger rate dominates the total rate for the three In contents studied; however, the relative difference between the hole-hole-electron and electron-electron-hole contributions decreases as the In content is increased to 25%. Our studies provide further insight into the origin of the "thermal droop"(i.e., the decrease in internal quantum efficiency with increasing temperature at a fixed carrier density) in (In,Ga)N-based light-emitting diodes. We find that the ratio of radiative to nonradiative (Auger) recombination increases in the temperature range relevant to the thermal droop (≥300 K), suggesting that the competition between these processes is not driving this droop effect in c-plane (In,Ga)N/GaN quantum wells. This finding is in line with recent experimental studies.