1:30 PM - 1:45 PM
[17p-Z27-3] Excitation wavelength dependence of temperature-induced photoluminescence quenching in InGaN quantum wells
Keywords:InGaN quantum wells, internal quantum efficiency, temperature-induced photoluminescence quenching
Internal quantum efficiency in III-nitride semiconductor light emitting layers is usually estimated from the experimental results of the temperature dependence of photoluminescence intensity. In this method, the internal quantum efficiency at extremely low temperature is assumed as 100%, and the decrease in emission intensity with increasing temperature is considered to be caused only by the decrease in internal quantum efficiency. Since the principle of the method is easy to understand and the measurement is relatively simple, it is frequently used. However, the method cannot always provide accurate values of the internal quantum efficiency. In this study, we have measured the temperature dependence of emission intensity at various excitation wavelengths for the same InGaN quantum-well sample, and have shown that the estimated internal quantum efficiency strongly depends on the excitation wavelength. Furthermore, the experimental results have been semi-quantitatively reproduced by the simple theoretical model in which the temperature dependence of excited carrier density due to temperature-induced bandgap shift.