Crystal orientation-dependent optical properties of mid-infrared GaInSb/GaInAlSb quantum well laser

The optical properties of compressively strained GaInSb quantum well (QW) laser fabricated in (001), (110), (111), (112) and (113) directions are theoretically investigated by solving one dimensional conduction and valence bands Schrödinger equation using finite difference method. The valence band mixing effect is found minimum in (113) direction and maximum in (111) orientation. The results obtained from the present study demonstrate that there is a strong correlation between the optical gain and its emission wavelength with crystal orientation of the QW material. The maximum and minimum optical gains are evaluated in the (113) and (111) crystal orientations, respectively. The peak emission wavelength can be tuned from 2.415 μm to 2.27μm by changing the crystal orientation from (110) to (111). It is also found that the threshold current and transparency carrier density are strongly dependent on the crystal orientation of the QW material.