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

Abstract

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 ${n}_{3D}=3.8\ifmmode\times\else\texttimes\fi{}{10}^{18}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$, we find total Auger coefficients in the range of $\ensuremath{\approx}6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}30}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{6}/\mathrm{s}$ (10% In) to $\ensuremath{\approx}3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}31}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{6}/\mathrm{s}$ (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 ($\ensuremath{\ge}300$ 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.