Gold impurity concentration in vapor-liquid-solid grown GaAs nanowires

Gold particles are commonly used as catalysts in the vapor-liquid-solid (VLS) growth of GaAs nanowires, but the incorporation of gold into the nanowires can negatively affect their electronic and optical properties. In this work, we investigate the equilibrium concentration of Au in GaAs nanowires using density functional theory calculations combined with thermodynamically assessed chemical potentials. Our results show that under typical VLS growth conditions, the Au concentration is strongly influenced by the growth temperature and the Ga concentration in the catalyst alloy particle. We find that minimizing Au incorporation requires low growth temperatures and high Ga content in the particles. The predicted equilibrium Au concentrations are consistent with experimental data, offering theoretical guidance for minimizing Au contamination during nanowire growth.