Luminescence efficiency and temperature quenching of spontaneous and stimulated emission in ultra-low dislocation density InN

In this letter, we evaluate temperature quenching of photoluminescence in ultra-high quality epitaxial InN films to assess the internal quantum efficiency (IQE) of band-to-band light emission. Measured room-temperature carrier lifetimes of ∼10 ns in the samples with record-low dislocation density of Nd ∼ 5 × 108 cm−2 appear consistent with the diffusion-limited Shockley–Reed–Hall recombination model and lead to a maximum emission IQE of ∼1.5% at T = 300 K. For the stimulated emission (SE) regime, dislocation densities in excess of 1010 cm−2 can be actually tolerated without seriously affecting the SE threshold, and its temperature dependence is determined by a competition between radiative and Auger processes, with a crossover point around liquid-nitrogen temperature.