Study of GaAsSb:N bulk layers grown by liquid phase epitaxy for solar cells applications

Abstract

We present an original study of bulk epitaxial GaAsSb:N layers in view of photovoltaic applications of this material. The layers are grown on n-GaAs substrates by low-temperature liquid phase epitaxy (LPE). The grown GaAsSb:N layers exhibit reproducible properties and good optical quality. A number of experimental methods including x-ray diffraction, energy dispersive x-ray spectroscopy, atomic force microscopy, x-ray photoelectron spectroscopy and Raman spectroscopy are applied for investigation of the structural properties, surface morphology, local arrangement and chemical bonding of Sb and N in the obtained compounds. The band gap values at room temperature assessed from surface photovoltage and photoluminescence (PL) measurements are in good agreement and are ∼20 meV lower than those of reference GaAsSb layers. PL spectra measured at different temperatures (10–300 K) show a very weak S-shape-like behaviour of the PL peak energy position indicating minimal carrier localization. The obtained results reveal the capacity of the LPE for growing bulk GaAsSb:N layers with good optical quality.