Spectral study of photoluminescence from GaInN/GaN MQWs using CW and time-resolved measurements

We have studied the recombination process of undoped and Si-doped Ga0.84In0.16N/GaN MQWs by using cw and time-resolved photoluminescence. It was found that the piezoelectric field strongly affects the recombination process of GaInN/GaN MQWs. Si doping in QWs was shown to be effective to screen the field. Two different recombination transitions have been observed for all MQW samples we have investigated with an energy difference of about 60 meV when excitation power is high. The peaks at the higher energy side show stimulated-emission-like characteristics for all samples. Since the estimated carrier density is higher than the Mott-transition level, we suggest that the stimulated emission is caused by an electron-hole plasma.