Carrier capture in InGaN quantum wells and hot carrier effects in GaN

Two new aspects of photoluminescence in GaN and alloys are presented. First, quantitative photoluminescence is carried out in a double InGaN/GaN quantum well structure. By comparing the luminescence intensities from both wells, we could extract the recombination velocities in both wells. We show that the capture is more efficient in a deeper well. Second, photoluminescence under strong excitation density is studied. Hot carrier phenomena are clearly demonstrated. From the high energy tail, we determine the electron temperature and we show that the main energy relaxation mechanism is the optical phonon emission. The effect of carrier temperature on the phonon replica on the low energy side of the luminescence peak is also emphasized.