Wavefunctions and Optical Gain in $\text{In}_{0.3} {\text{Ga}}_{0.7} {\text{As}}/{\text{GaAs}}_{0.4} {\text{Sb}}_{0.6}$ Type-II Double Quantum Well Nanoheterostructure Under External Uniaxial Strain

Abstract

Variations in wavefunction confinement under external uniaxial strain are observed to affect the optical gain obtained in type-II quantum well nanodimension heterostructures. This paper reports the wavefunctions and optical gain realized in ${\text{In}}_{0.3} {\text{Ga}}_{0.7} {\text{As}}/{\text{GaAs}}_{0.4} {\text{Sb}}_{0.6}$ type-II double QW heterostructure under uniaxial strain along [001]. Energy bands, wavefunctions of confinement states in the structure and optical gain of the heterostructure under electromagnetic field perturbation are presented. The $6 \times 6$ k·p Hamiltonian matrix is considered, and Luttinger–Kohn model has been applied for the electronic band structure calculations. Optical gain spectra of the double QW nanoheterostructure under external uniaxial strain of 1, 2 and 5 GPa, respectively, is calculated. The optical gain curve shows a significant improvement in gain under external uniaxial strain along [001] at 300 K. For a charge carrier injection of $8 \times 10^{12} /{\text{cm}}^{2}$, the optical gain is 9170 in x polarization. The heterostructure is seen to be operating in the energy range of 0.65–0.8 eV (1549–1907 nm). Thus, a wide range wavelength tuning can be realized.