LAUSR

The mechanism behind the quantum-well-width dependent Shockley-Read-Hall (SRH) recombination lifetime is investigated in the InGaN/GaN quantum wells (QWs). According to the literature, the strong dependence of SRH lifetime on QW width is proposed to originate from the electron-hole separation in c-plane QWs, just as the radiative recombination. However, in this work, by temperature dependent steady-state time-resolved photoluminescence experiment, it is found that besides the QW width, the SRH lifetime also increases significantly with increasing QW number, which cannot be explained by the electron-hole separation. The two kinds of dependences of SRH lifetime can be attributed to the same source, judging from their similar activation energies, which is the existence of indium atoms compensating the SRH recombination centers generated during the epitaxy and thereby prolonging the SRH lifetime. The density of SRH centers deduced from our analysis decreases with the total thickness of the InGaN layer in a consistent manner for both the QW-width dependent and QW-number dependent sets of samples.