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 92 nm after annealing at 800 degrees C for 30 s. Intermixing also results in large wavelength tuning from 1.6 to 1.37 mu m 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.