Temperature dependence of carrier lifetimes in InN

Time-resolved pump–probe transmission measurements were used to determine the temperature dependence of carrier lifetime for InN epilayers with unintentionally doped levels from 10 to 10 cm. The observed decay time at 20 K is well explained by a dominating radiative interband recombination, while at room temperature it is attributed to a defect related nonradiative recombination channel. The temperature dependence of the radiative lifetime is deduced from the measurements of both differential transmission decay time and PL intensity. For the best quality sample, we find the radiative lifetime increases proportionally to T , as theory predicts when a k-selection rule holds, which suggests that the radiative bandto-band transition accounts for the observed infrared photoluminescence over the entire temperature.