Theory of optical and electronic properties of semiconductor heterostructures with many-body effects.

Optical and electronic properties of semiconductors heterostructures are analyzed, combining many-body and band structure engineering techniques. The Coulomb interaction is considered in different excitation regimes. For the low density excitonic limit, it is shown that superlattices can be modelled as 3D effective anisotropic media and the method is applied to the computation of exciton binding energies. In the high density regime, coupled band optical Bloch equations are obtained, combining Coulomb effects with the solutions of the Luttinger Hamiltonian, and the problem is solved in general under quasi-equilibrium conditions. Expressions for the band gap shift and the Coulomb enhancement in a Pade' approximation are obtained and solved in the context of a quasi-statically screened Coulomb interaction. The resulting equations are used to study the influence of band-structure and many-body effects in the gain and α-factor of both lattice-matched and strained quantum well lasers