Calculation of the Bandgap of Dilute Nitride GaAsSbN Alloys

Abstract

Dilute nitrides are semiconductor alloys, obtained from the conventional III-V compounds by incorporating a small amount of nitrogen. In this work, we focus on GaAsSbN considered as a perspective material for incorporation in multijunction solar cells. Nitrogen creates a localized level inside the conduction band continuum. The interaction of this level with the conduction band is usually described by the single band anti-crossing (BAC) model. The double BAC model of GaAsSbN considers both the N and the Sb localized levels in the conduction and the valence band, respectively. We calculate the bandgap energy of GaAsSbN employing the double BAC model for different concentrations of Sb and N. Parameters of the BAC model taken from different literature sources are used in the calculations and their influence on the final result is explored. Finally, the calculated bandgap energies are compared to experimental data of GaAsSbN layers grown on n-GaAs substrates by low-temperature liquid phase epitaxy. These data include the optical absorption edge of the material determined by surface photovoltage spectroscopy and the energy position of the photoluminescence peak at room temperature.