Analytically calculated liquid–solid composition dependencies for self- and gold-catalyzed InSbxAs1–x nanowires.

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.

Semiconductors made of earth-abundant elements, such as zinc phosphide, have the potential to substitute less abundant, highly functional compound semiconductors such as InAs or InP.

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Antimonide-based nanowires represent an important new class of material with great promise for both fundamental physics studies and various device applications. We report a comprehensive study on understanding the growth behaviour of GaxIn1-xSb nanowires on GaAs substrates using Au nanoparticles. First, the effect of growth parameters on the morphology and composition of GaxIn1-xSb nanowires is extensively studied over the entire compositional range (from 3 to ~100% of In). Second, the obtained compositional results are explained by a kinetic model, suggesting an Arrhenius-type behavior for the trimethylindium (TMIn) precursor. Third, the particle composition is fully investigated and the implications for growth are discussed with reference to our calculated Au-Ga-In phase diagram. Fourth, a mechanism is presented to explain the temperature-dependent morphology and radial growth of the GaxIn1-xSb nanowires. Finally, we demonstrate homogeneous compositions in both axial and radial directions and the nanowires remain entirely twin-free zinc blende. The understanding gained from this study together with the potential to precisely tailor the band gap, wavelength and carrier mobilities allows fabrication of various GaxIn1-xSb-based nanowire devices.

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The Au-In-Ga ternary phase diagram is of importance for understanding the involved thermodynamic processes during the growth of Au-seeded III-V heterostructure nanowires containing In and Ga (e.g. Au-seeded InAs/GaAs nanowires). In this work the Au-In-Ga system has been thermodynamically modeled using the CALPHAD technique based on a recent experimental investigation of the phase equilibria in the system. As a result, a set of selfconsistent interaction parameters have been optimized that can reproduce most of the experimental results.