GREENS-FUNCTION APPROACH TO THE ELECTRONIC-STRUCTURE OF DOUBLE-BARRIER QUANTUM-WELL HETEROSTRUCTURES

The scattering-theoretic Green's-function method incorporated with ban d structures, which takes into account the indirect band gap, the band nonparabolicity, and the multiorbital and external-bias effect, is us ed to study AlAs/CaAs/AlAs double-barrier quantum-well structures in a [001] direction. The calculated spectral local density of states simu ltaneously exhibits confined states originating from both the quantum- well Gamma valley and the barrier X valley. The calculated energies of confined quantum-well electron states and light-hole states are compa red with the reported photoluminescence-excitation experimental data.