Effect of antimony on uniform incorporation of nitrogen atoms in GaInNAs films for solar cell application

In this work, we have investigated the effect of antimony (Sb) on the uniform incorporation of nitrogen atoms in GaInNAs alloy grown with different levels of Sb fluxes. The photoluminescence (PL) intensity and full-width at half maximum (FWHM) are both improved for a narrow range of Sb flux between 1×10−8 and 5×10−8 Torr, in which Sb plays the role of surfactant. On the other hand, higher level of Sb flux deteriorates the PL characteristics most likely due to Sb-related defects. Furthermore in temperature dependent PL measurements, drastic peak energy shifts were observed in all samples, which indicate a strong carrier localization. Although GaInNAs sample showed a large energy shift of 53 meV, supply of Sb decreased the localization energies to 13–22 meV. These results show that optimized amount of Sb, maintaining a high growth temperature of 520 °C, enhances the homogeneity of potential energy in conduction band of GaInNAs alloy, since the carrier localization is led by inhomogeneous N incorporation.

► We introduce antimony as a surfactant in MBE-grown GaInNAs films.
► Optimum amount of antimony improves PL properties of GaInNAs films.
► Carrier localization in GaInNAs CB is observed due to potential fluctuation.
► Potential fluctuation is improved by introducing antimony during GaInNAs growth.
► Reduction of potential fluctuation leads to improved solar cell performances.