Abstract
We report selective postgrowth band gap tuning of
In
As
∕
In
Ga
Al
As
quantum dots-in-well grown on InP substrate using impurity-free group-III intermixing. In contrast to most reported intermixing results,
Si
x
N
y
annealing cap results in a larger band gap blueshift than
Si
O
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
μ
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.