1-eV GaNAsSb for multijunction solar cells

We report on the growth of 1-eV GaNAsSb lattice- matched to GaAs as an alternative material to the most commonly used GaInNAs(Sb). GaNAsSb layers were grown by plasma assisted molecular beam epitaxy with different N and Sb compositions. The electronic and optical properties of the layers were probed using photoluminescence and photoreflectance spectroscopy and compared to the band anticrossing model. The incorporation mechanism of the group-V elements were investigated using secondary ion mass spectrometry. It was found that Sb does not affect the N incorporation. Moreover increasing the N flux increased the N composition at the expense of the Sb composition. Post-growth annealing was investigated and found to greatly improve the photoluminescence intensity.