Photoluminescence properties of localized states caused by nitrogen alloying in a GaInNAs/GaAs single quantum well

We have investigated photoluminescence (PL) properties of localized states induced by nitrogen alloying in a Ga1−xInxNyAs1−y/GaAs single quantum well (SQW) with x=0.33 and y=0.008, comparing with those in a Ga1−xInxAs/GaAs SQW without nitrogen. In order to determine the intrinsic band edge, we also used photoreflectance (PR) spectroscopy that is sensitive to the optical transitions at critical points. The PR line width of the band-edge transition in the GaInNAs/GaAs SQW is much broader than that in the GaInAs/GaAs SQW, which indicates that considerable disorders are introduced by nitrogen alloying. The PL-peak energy of the GaInNAs/GaAs SQW, which has a Stokes shift of ∼20 meV at 10 K, continuously shifts to the band edge with an increase in excitation power, reflecting the localization nature of carriers. The PL-decay profile related to the localized states clearly exhibits a stretched exponential feature peculiar to a disordered system. It is concluded that the PL properties at low temperature are dominated by random potentials caused by nitrogen alloying.