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, Si _xN _y annealing cap results in a larger band gap blueshift than SiO ₂ annealing cap with a differential shift of 92 nm after annealing at 800°C for 30 s. Intermixing also results in large wavelength tuning from 1.6 to 1.37 μm 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.