Optimum annealing temperature versus nitrogen composition in InAs/(Ga, In) (N, As) quantum dots

The effect of annealing on long-wavelength emitting InAs/Ga0.85In0.15NxAs1- x ( 0 <= x <= 0.023) quantum dots ( QDs) is studied. For the as-grown sample with x = 0.023, a room temperature photoluminescence ( PL) emission wavelength of 1.58 mu m is achieved. It is found that the optimum annealing temperature increases when the nitrogen composition in the cap layer increases. After optimum annealing, the QD PL emission exponentially blue-shifts with the nitrogen composition, whereas the as-grown QD emission energy red-shifts with a linear behavior. This implies that to get the longest PL wavelength with the best PL efficiency, the nitrogen composition should not exceed 2%.