Excitation power dependent photoluminescence of In 0.7Ga 0.3As 1−xN x quantum dots grown on GaAs (0 0 1)

Abstract

The excitation power dependent photoluminescence (PL) of self-assembled In 0.7Ga 0.3As 1− x N x ( x = 0 , 0.02 ) quantum dots (QDs) has been investigated in the excitation power density ranged from 3.0 kW/cm 2 to 50 mW/cm 2. As the excitation power increases, the emission peak of In 0.7Ga 0.3As 0.98N 0.02 QDs shifts to shorter wavelengths, while the peak of In 0.7Ga 0.3As QDs remains at the same wavelength. In the low-excitation cases, the PL peak of the In 0.7Ga 0.3As 0.98N 0.02 QDs has a tail on the lower energy side, on the other hand, that of the In 0.7Ga 0.3As QDs shows a symmetrical shape. Since the dot size distribution of the In 0.7Ga 0.3As 0.98N 0.02 QDs is similar to that of the In 0.7Ga 0.3As QDs, this blue-shift and the lower energy tail of the PL peak of the In 0.7Ga 0.3As 0.98N 0.02 QDs are attributed to the nitrogen-related states below the conduction band edge as are observed in the case of InGaAsN quantum wells (QWs).