Cathodoluminescence characterization of the band gap energy in dilute nitride GaNSbAs alloys [Poster]

Abstract

The development of a high quality 1eV material is one of the most import challenges in high efficiency solar cells development. The GaInP/GaInAs/1eV/Ge structure attained one of the highest solar cell efficiency, 44.0%. The dilute nitride GaNSbAs has attracted a considerable interest, since this alloy can be grown lattice-matched to GaAs with a bandgap of 1eV. However, It is well-known that N incorporation in dilute nitrides is associated with the generation of structural defects and as a result, the degradation of the optical properties. Thermal annealing is the most common procedure to improve the dilute nitrides response. In order to have a deeper understanding of the GaNSbAs layer behaviour, the effects of ex-situ annealing in N-atmosphere and in-situ annealing in As-atmosphere, have been investigated. Samples have been analysed for the first time by cathodoluminescence (CL), being this technique a good method for getting direct information in a simple, fast and non-destructive way about compositional gradients. It has been supported by scanning transmission electron microscopy (STEM) and energy dispersive spectroscopy (EDS).