Metalorganic molecular-beam epitaxy and characterization of GaAsNSe/GaAs superlattices emitting around 1.5-μm-wavelength region

Abstract

GaAsNSe/GaAs superlattices (SLs) were grown on GaAs(001) substrates by metalorganic molecular-beam epitaxy. Strong photoluminesence (PL) emission around the 1.5-μm-wavelength region was observed from these SLs without thermal annealing, which suggests that high electron concentrations in GaAsNSe layers increase the radiative recombination rate, making the nonradiative recombination relatively unimportant. It is also demonstrated that (GaAsNSe/GaAs SLs)/(GaAsN/GaAsSb SLs)/GaAs heterostructures are effective to reduce the strain accumulation in the layers, which will also form effective separated confinement heterostructure. The temperature dependence of the PL peak intensity is drastically improved by combining the GaAsN/GaAsSb SLs with the GaAsNSe/GaAs SLs following this scheme. The PL peak intensity observed at 300 K was as large as 20% of that observed at 19 K. This improvement of the optical property will be attributed to the elimination of nonradiative defects by minimizing average strain in the samples.