High internal quantum efficiency of long wavelength InGaN quantum wells

Time-resolved and quasi-cw photoluminescence (PL) spectroscopy was applied to measure the internal quantum efficiency (IQE) of c-plane InGaN single quantum wells (QWs) grown on sapphire substrates using metal-organic chemical vapor deposition. The identical temperature dependence of the PL decay times and radiative recombination times at low temperatures confirmed that the low temperature IQE is 100%, which allowed evaluation of the absolute IQE at elevated temperatures. At 300 K, the IQE for QWs emitting in green and green-yellow spectral regions was more than 60%. The weak nonradiative recombination in QWs with a substantial concentration of threading dislocations and V-defects (similar to 2 x 10(8) cm(-2)) shows that these extended defects do not notably affect the carrier recombination.