Study of Laser Threshold Temperature Sensitivity in Optically Pumped GaN Epilayers

On the base of experimental spontaneous emission spectra measured at laser threshold the temperature dependencies of the radiative R sp and nonradiative Q recombination rates as well as the spontaneous emission internal quantum efficiency η sp for optically pumped wurtzite GaN/Al 2 O 3 epilayers have been calculated. The recombination rate induced by the amplified luminescence R lum was taken into account. It is shown that the main reason of the increasing threshold pump rate R p with temperature T for the GaN‐based compounds is a substantial rise of the nonradiative recombination rate. The portion of Q in R p exceeds 80–90%. The contributions of R sp and R lum in R p amount to several percents. The η sp value is of 0.12–0.18 within the temperature interval of 300–450 K. Further increase in T leads to an abrupt decrease in η sp down to 0.06 at 517 K.