Plasma heating in highly excited GaN/AlGaN multiple quantum wells

Time-resolved photoluminescence (PL) spectroscopy was used to investigate carrier distributions in a GaN/AlGaN multiple quantum well (MQW) sample under high excitation intensities necessary to achieve lasing threshold. Room temperature PL spectra showed optical transitions involving both confined and unconfined states in the quantum well structure. Analysis of the experimental results using a microscopic theory, indicates that at high excitation the carrier distributions are characterized by plasma temperatures which are significantly higher than the lattice temperature. The implications of our findings on GaN MQW laser design are also discussed. © 1998 American Institute of Physics.