Steady-state recombination lifetimes in polar InGaN/GaN quantum wells by time-resolved photoluminescence

Abstract

Both the steady-state radiative and nonradiative recombination lifetimes of excess carriers in polar InGaN/GaN quantum wells are extracted by a novel technique. Instead of the conventional ultrashort-pulsed laser, a modulated CW laser is utilized as the excitation source in time-resolved photoluminescence (PL) experiments to obtain the steady-state lifetimes. By analyzing the dependence of the PL lifetime and the integrated PL intensity on the injected power density simultaneously, both the radiative and Shockley–Read–Hall (SRH) recombination lifetimes can be determined accurately. The proposed method is applied to study the radiative and nonradiative processes in polar InGaN/GaN quantum wells with various well widths. The results suggest that both the SRH lifetime of holes and the radiative recombination lifetime increase drastically with increasing well width, while the SRH lifetime of electrons exhibits a weaker dependence on well width.