Extended wavelength mid-infrared photoluminescence from type-I InAsN and InGaAsN dilute nitride quantum wells grown on InP

Extended wavelength photoluminescence emission within the technologically important 2–5 micrometer spectral range has been demonstrated from InAs1xNx and In1yGayAs1xNx type I quantum wells grown onto InP. Samples containing N 1% and 2% exhibited 4K photoluminescence emission at 2.0 and 2.7 lm, respectively. The emission wavelength was extended out to 2.9 lm (3.3 lm at 300 K) using a metamorphic buffer layer to accommodate the lattice mismatch. The quantum wells were grown by molecular beam epitaxy and found to be of a high structural perfection as evidenced in the high resolution x-ray diffraction measurements. The photoluminescence was more intense from the quantum wells grown on the metamorphic buffer layer and persisted up to room temperature. The mid-infrared emission spectra were analysed, and the observed transitions were found to be in good agreement with the calculated emission energies

Valence band hybridization in N-rich GaN1-xAsx alloys

We have used photo-modulated transmission and optical absorption spectroscopies to measure the composition dependence of interband optical transitions in N-rich GaN{sub 1-x}As{sub x} alloys with x up to 0.06. The direct bandgap gradually decreases as x increases. In the dilute x limit, the observed band gap approaches 2.8 eV; this limiting value is attributed to a transition between the As localized level, which has been previously observed in As-doped GaN at 0.6 eV above the valence band maximum in As-doped GaN, and the conduction band minimum. The structure of the valence band of GaN{sub 1-x}As{sub x} is explained by the hybridization of the localized As states with the extended valence band states of GaN matrix. The hybridization is directly confirmed by soft x-ray emission experiments. To describe the electronic structure of the GaN{sub 1-x}As{sub x} alloys in the entire composition range a linear interpolation is used to combine the effects of valence band hybridization in N-rich alloys with conduction band anticrossing in As-rich alloys