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We present a generalized theoretical description of the 24×24 k.p approach for determining the band structure of the direct-band-gap semiconductors (GaAs, InAs) as well as the indirect-band-gap semiconductor (Ge), including far-level contribution (essentially the d levels). We extend the sp3s* basis functions by the inclusion of sV* orbitals. We find that the sp3“d”(s*)2 k.p model is fairly sufficient to describe the electronic structure of these systems over a wide energy range, obviating the use of any d orbitals. Finally, the comparison with available experimental and theoretical results shows that the present model reproduces known results for bulk GaAs, InAs, and Ge, that is, their band structure, including s and p valence bands and the lowest two conduction bands.

The band structure of direct-band-gap semiconductor (InAs) and indirect-band-gap semiconductor (Ge) is described theoretically using a 20×20 k.p model and including far-level contribution (essentially the d levels). By using this model, we obtained a quantitatively correct description of the top of the valence band and the lowest two conduction bands both in terms of energetic positions and band curvatures. In particular, the k.p Hamiltonian parameters are adjusted such that the transverse mass of the germanium conduction band is equal to the experimental value of 0.081.

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 InAs 1-x N x /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.

The band structure of direct-band gap semiconductors (GaAs, InAs, InP) is described theoretically by using a 34×34 k⋅p model. We extend the sp3d5 basis functions by the inclusion of sV∗ orbitals. We find that the sp3d5s∗ k⋅p model is sufficient to describe the electronic structure of all materials investigated over a wide energy range, obviating the use of any d valence orbitals. Finally, our results show that Luttinger parameters, the κ valence band parameter, the effective Landé factor g∗, and the effective-masses in the X and L valleys are in good agreement with available experimental data. In particular, the adjustment of the k⋅p Hamiltonian parameters proved that g∗ of GaAs, InAs, and InP are, respectively, −0.41, −15.82, and 1.35, which are in good agreement with the experimental values of −0.44, −14.90, and 1.26.

We present a theoretical study of band structure and optical gain spectra of dilute-N InAsN/GaSb/InAsN and the similar N-free InAs/GaSb/InAs laser structures, which have a “W” band alignment. Calculations are based on a 10×10 k⋅p model incorporating valence, conduction, and nitrogen-induced bands. The two laser diodes are designed to operate at 3.3 μm at room temperature. We find that the incorporation of a few percent of nitrogen in the laser active region improves optical gain performance, which leads to a peak gain value of approximately 1000 cm−1 for a typical injection carrier concentration of 1×1012 cm−2 and a carrier transparent density of 0.54×1018 cm−3.

New dilute-nitride InAsN/GaSb laser diodes on an InAs substrate with a 'W' or 'M' design are theoretically investigated using a ten-band k • p model including valence, conduction and nitrogen-induced bands. For these laser diodes, designed to operate at 3.3 μm at room temperature, optical transition matrix elements for TE and TM modes between the valence sub-bands and the conduction sub-bands, modal gain and total threshold current densities are calculated. Under the hypothesis of a total loss coefficient α = 50 cm −1 , non-conventional 'W' and 'M' multiquantum well laser structures present a calculated threshold current density J th lower than 1.1 kA cm −2 .