GaAsSbN–GaAsSb–InP Type-II “W” Quantum Wells for Mid-IR Emission

A GaAsSbN-GaAsSb-InP type-II ldquoWrdquo quantum well (QW) structure is proposed for achieving emission in the mid-infrared (IR) wavelength region. Simulation studies based on the band anticrossing model and a 10-band k-p Hamiltonian demonstrate that emission wavelengths as long as 3 mum could be achieved on an InP substrate, limited primarily by strain relaxation considerations. The incorporation of nitrogen into GaAsSb grown on InP leads to band-gap narrowing and a deepening of the conduction band offset. The energy band structure, interband emission wavelengths, and optical matrix elements are evaluated for a GaAsSbN-GaAsSb-InP SL structure design. A structure design utilizing the lowest Sb content for the GaAsSbN electron wells and the highest Sb content for the GaAsSb hole wells, within strain limitations, provides the longest wavelength emission. The electron and hole effective masses of bulk GaAsSbN are extracted from the computed energy band structure as a function of Sb and N composition. The electron effective mass of GaAsSbN is found to remain nearly constant with N for low N-composition alloys. The heavy- and light-hole effective masses decrease slightly with increasing N composition.