Localization characteristics of photoluminescence decay dynamics in an InxGa1−xAs1−yNy/GaAs single quantum well

We have investigated photoluminescence (PL) properties of an In x Ga 1-x As 1-y N y /GaAs single quantum well from an aspect of carrier localization. The sample was grown on a (001) GaAs substrate by metalorganic vapor phase epitaxy: the In x Ga 1-x As 1-y N y thickness is 8 nm, and the alloy compositions of x and y are 0.15 and 0.034, respectively. The PL spectra at low temperatures lie on the low energy side of the band edge confirmed by photoreflectance spectroscopy, and the PL peak energy approaches to the band edge with increasing excitation power. These results demonstrate the localization characteristics of the PL process. It has been found that the PL decay of localized carriers exhibits a stretched exponential profile that is a typical decay phenomenon in a disordered system. From the energy dependence and temperature dependence of the stretched exponential profile, we conclude that the PL decay dynamics at low temperatures are dominated by random potentials due to alloy disordering of InGaAsN.