LAUSR

Despite the unavoidable presence of silicon atoms in the catalyst alloy droplets during the vapor–liquid–solid growth of III–V nanowires on silicon substrates, it remains unknown how the nucleation of nanowires is affected by these foreign atoms. In this work, we present the first attempt to quantify the nanowire nucleation rate versus the silicon concentration in the droplet. We calculate the chemical potential difference per Ga–As pair in the quaternary Au–Ga–As–Si liquid alloy droplet and in solid state, and compare it to the ternary Au–Ga–As droplet without silicon. This allows us to compute the nucleation rates of GaAs nanowires versus the silicon concentration under different conditions. We find that the presence of silicon in the droplet decreases the nucleation probability of GaAs nanowires for gallium-rich droplets (with the gallium contents cGA greater than 0.6) and increases it for gold-rich droplets (cGA < 0.6). The model is used to explain our experimental data for hydride vapor phase epitaxy...