Temperature-dependent PL of InGaN/GaN multiple quantum wells with variable content of in

Temperature-dependent photoluminescence (PL) of InGaN/GaN multiple quantum wells (MQWs) is studied. Three samples have different percentage composition of In: 10%, 14% and 17%. With increasing temperature, we can observe 'S-shaped' behavior of the peak energy for all three samples. Because the second temperature turn of the 'S-shaped' curves are different for each samples, and the blueshift energy of 10 meV in our samples is less than the energy shift result from QCSE, the S-shape is unrelated with QCSE. By using multi-channel Arrhenius plot formula, the samples' activation energies are calculated, which stand for the level of localized In-cluster. And it is found that both the activation energies and the second temperature turn of the 'S-shaped' curves increase with increasing the content of indium for three samples. This phenomenon can be demonstrated by the reason that the sample which containing much In has lager activation energy, the photo-carriers need much thermal energy to get out of the local potential minima induced by In-cluster. These results further illustrate that the emission of InGaN/GaN multiple quantum wells is due to the radiative recombination of excitons localized in potential minima induced by In-cluster.EI06864-8693