Envelope Function Approximation (EFA) bandstructure calculations for III-V non-square stepped alloy quantum wells incorporating ultra-narrow (5 Angstrom) epitaxial layers

Citation:
Kaduki KA, Batty W. "Envelope Function Approximation (EFA) bandstructure calculations for III-V non-square stepped alloy quantum wells incorporating ultra-narrow (5 Angstrom) epitaxial layers." Physica Scripta. 2001;61(2):213-221.

Abstract:

We describe Envelope Function Approximation (EFA) bandstructure calculations based on a 4-band electron (EL), heavy-hole (HH), light-hole (LH) and split-off hole (SO) effective mass Hamiltonian, with Burt-Foreman hermitianisation, which can handle III-V quantum well structures that incorporate ultra-narrow epi-layers. The model takes into account the coupling of EL, HH, LH and SO bands and is suitable for describing quantum wells tuned to the 1.0 - 1.55 µm window exploited by optical fibre communication devices. We have used the multi-band solver to calculate the bandstructure of an illustrative InGaAsSb-AlGaSb non-square quantum well that incorporates 6Å potential "spikes" in its well region. Calculations based on the Burt-Foreman hermitianised Hamiltonian and those based on a Hamiltonian with standard "symmetrised" hermitianisation are presented and compared. When coupling to the conduction band is excluded from the calculation, the latter formulation leads to anomalous electron-like curvature of the dispersion curves for our spiked non-square quantum well structure

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