Study on carrier lifetimes in InGaN multi‐quantum well with different barriers by time‐resolved photoluminescence

The carrier lifetimes depending on emission photo energy of InGaN multi-quantum well (MQW) with different barriers are studied by time-resolved photoluminescence (TRPL). A two-exponential decay process is observed for the high-energy photons. This is explained by there being two types of carrier localization centers (LCs), shallow localization centers (SLCs), and deep localization centers (DLCs), in InGaN quantum wells. The radiative recombination efficiency (RRE) of a quantum well is mainly determined by carrier dynamics in the DLCs. Compared to the conventional InGaN/GaN MQW, the MQW with the first barrier of 60-nm In0.01Ga0.99N, has the smaller and denser DLCs, and hence the higher RRE, and for the MQW with all the barriers of In0.02Ga0.98N, the average and total area of DLCs both become larger. It can maintain the similar RRE but much shorter carrier lifetime of tens of ns in DLCs. It is considered that the state of LCs is strongly dependent on the strain in MQW. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim