Group-III intermixing in InAs∕InGaAlAs quantum dots-in-well

We report selective postgrowth band gap tuning of InAs∕InGaAlAs quantum dots-in-well grown on InP substrate using impurity-free group-III intermixing. In contrast to most reported intermixing results, SixNy annealing cap results in a larger band gap blueshift than SiO2 annealing cap with a differential shift of 92nm after annealing at 800°C for 30s. Intermixing also results in large wavelength tuning from 1.6to1.37μm at room temperature, accompanied by luminescence linewidth reduction and intensity improvement. According to our theoretical model, we postulate that the unusual In(GaAl)As intermixing is governed by different interdiffusion rates of group-III atoms.