Annealing effects on the temperature dependence of photoluminescence characteristics of GaAsSbN single-quantum wells

摘要

In this work we investigate the effects of ex situ annealing in N ambient and in situ annealing in As ambient on the temperature dependence of photoluminescence (PL) spectral characteristics of GaAsSbN/GaAs single-quantum-well heterostructures. The focus of this work is on three representative nitride samples grown by molecular-beam epitaxy. The widths of the quantum wells (QWs) varied from 8 to 9 nm and the concentrations of nitrogen and antimony as determined from high-resolution x-ray diffraction and secondary-ion-mass spectroscopy were in the range of 0.8%-1.4% and 26%-33%, respectively. One sample was ex situ annealed in N ambient at 700℃ for 10 min. Two other samples were in situ annealed in As ambient at 650 and 700 °C, respectively, also for 10 min. Excitonic transitions in the QWs exhibit the well-known "S-curve" behavior in the temperature dependence of the PL peak energy. In addition, the variation of the full width at half maximum with temperature exhibits an "inverted S-curve" behavior. These are well-known signatures of localized excitons. The PL characteristics such as total integrated intensity and full width at half maximum as well as their temperature dependence, and the quality x-ray rocking curves clearly indicate that in situ annealing is more effective in reducing the densities of the localized states and of nonradiative recombination centers leading to better quality quantum well structures.