Many-body optical gain and intraband relaxation time of wurtzite InGaN/GaN quantum-well lasers and comparison with experiment

The optical gain and the intraband relaxation time of wurtzite InGaN/GaN QW lasers are investigated theoretically considering the non-Markovian gain model with many-body effects. Gain spectra are compared with those obtained from the experiment. The calculated intraband relaxation time is about 24 fs at the subband edge and gradually increases with the energy. The intraband relaxation time is shown to be nearly independent of the sheet carrier density in an investigated range. The calculated gain spectra is in good agreement with the experiment. The intraband relaxation time tau(in) obtained from fitting with experiment is 25 fs. This value agrees well with the calculated value (similar to 24 fs) at the subband edge, for which most of optical transitions occur. (c) 2005 American Institute of Physics.