Characteristics of GaAsN∕GaAsSb type-II quantum wells grown by metalorganic vapor phase epitaxy on GaAs substrates

Pseudomorphic four-period GaAs0.978N0.022∕GaAs0.78Sb0.22 type-II multiquantum well structures were grown on (100) GaAs substrates by metalorganic vapor phase epitaxy at 530°C. The GaAs0.978N0.022 layers were grown at a V/III ratio of 685 and N∕V ratio of 0.96, whereas the GaAs0.78Sb0.22 was grown at a V/III ratio of 3.8 and Sb∕V ratio of 0.8. The superlattice peaks in the x-ray diffraction θ-2θ scans around the (400) GaAs peak were fitted using a dynamical simulation model to determine layer thickness and alloy compositions. The GaAsN and GaAsSb thicknesses were ∼8nm and ∼5nm, respectively. The photoluminescence (PL) spectra were obtained at 30K and the PL peak energy was found to match the type-II transition energy obtained from a 10-band k∙p model. Postgrowth annealing under arsine-H2 with a N2 cooldown was found to increase the low temperature PL intensity and result in the appearance of luminescence at room temperature.