Recombination processes in structures with GaN/ALN quantum dots

• Photoluminescence temperature dependence of GaN/AlN quantum dots has been studied.
• Calculated radiative lifetime 1.5 times increases with temperature in 5–300 K range.
• Nonradiative lifetime in GaN QD was calculated in configuration coordinate model.
• Nonradiative recombination of carriers mainly occurs before capture in QDs.

Mechanisms of the generation and the radiative and nonradiative recombination of carriers in structures with GaN quantum dots in the AlN matrix are studied experimentally and theoretically. Absorption, stationary and nonstationary photoluminescence of quantum dots at different temperatures are investigated. It is found that the photoluminescence intensity considerably decreases with the temperature while the photoluminescence kinetics weakly depends on the temperature. The photoluminescence kinetics is shown to be determined by radiative recombination inside quantum dots. A mechanism of nonradiative recombination is proposed, according to which the main reason for the thermal quenching of photoluminescence is nonradiative recombination of charge carriers, generated by optical transitions between quantum dots and wetting layer states.