Composition of Gold Alloy Seeded InGaAs Nanowires in the Nucleation Limited Regime

We explain the composition of gold alloy particle seeded InGaAs nanowires in the nucleation limited regime. We use binary nucleation modeling to account for the nucleation of InGaAs from a supersaturated quaternary liquid alloy particle containing Au, In, Ga, and As. In our modeling we use realistic chemical potential differences between the seed particle and the nanowire. The chemical potentials are calculated from assessed thermodynamic parameters for Au, In, Ga, As, InAs, and GaAs in all relevant phases. Using binary nucleation theory we are able to link the composition of the seed particle to the composition of the nanowire under different conditions. We vary the seed particle concentrations of As, Ga, and In and the temperature. For each of these conditions, we calculate the Gibbs free energy landscape for nucleation. The size and composition of the critical nucleus is given by the location of the saddle point in this free energy landscape. We foresee that these results will be essential for understanding the limitations of composition control in gold alloy seeded InGaAs nanowires.