Auger Recombination From First-principles in Group-III Nitride Alloys

The group-III nitrides are widely used in optoelectronic devices like LEDs and lasers. However, at high power these materials have a drop in efficiency. This has been attributed to non-radiative Auger recombination. Experimental measurements of Auger and other nonradiative processes are difficult, making first-principles atomisc simulations vital to gaining a better understanding of how carriers recombine. We use density functional theory and many-body perturbation theory to study Auger and radiative rates in group-III nitride alloys. Our previous results have shown that in pure GaN, Auger primarily occurs through the assistance of phonons, while in pure InN, Auger occurs without assistance from other mechanisms. More interesting for optoelectronics are AlGaN and InGaN alloys, for which Auger is also assisted by alloy disorder. We will discuss results of our calculations on special quasirandom structures of AlGaN and InGaN over their complete composition range. Our findings provide insight into the microscopic origin of Auger and suggest approaches to reduce its impact on the efficiency of nitride devices.