Abstract
In this work, we present a theoretical analysis of the anisotropic hole subband states and optical gain spectra for various growth directions [h h l] such as [0 0 1], [1 1 0], [1 1 2], [1 1 3] and [1 1 1] of dilute-nitride InAs1-x Nx /GaSb with a 'W' and 'M' design. We show that the dispersion relation of hole subband states, hole effective mass, optical gain and threshold current density in [1 1 1] direction differ considerably from the other directions in particular the habitual direction [0 0 1]. There is a slight difference between the results of optical and modal gain for the other [1 1 0], [1 1 2] and [1 1 3] growth directions. Finally, we can predict that the optical performance of the 'M' design structure is more convenient for an emission in the mid-infrared (MIR) than that of the 'W' QW structure for x = 0.02.