Abstract
The intermixing enhancement in
In
Ga
As
∕
In
Ga
As
P
quantum well laser structure has been investigated using the Ge-doped sol-gel derived
Si
O
2
encapsulant layer. A band-gap shift of
∼
64
nm
has been observed from 16% Ge-doped
Si
O
2
capped sample at the annealing temperature of
630
°
C
with effective intermixing suppression using the e-beam-evaporated
Si
O
2
layer. Ge incorporation in the sol-gel cap reduces the mismatch of thermal expansion coefficients efficiently retaining preferential vacancies, and therefore enhancing the interdiffusion rate. The intermixed material retains a good surface morphology and preserves the optical quality as evidenced by the absence of any appreciable photoluminescence linewidth broadening.