Impact of preferential indium nucleation on electrical conductivity of vapor-liquid-solid grown indium-tin oxide nanowires

Highly conductive and transparent indium-tin oxide (ITO) single-crystalline nanowires, formed by the vapor-liquid-solid (VLS) method, hold great promise for various nanoscale device applications. However, increasing an electrical conductivity of VLS grown ITO nanowires is still a challenging issue due to the intrinsic difficulty in controlling complex material transports of the VLS process. Here, we demonstrate a crucial role of preferential indium nucleation on the electrical conductivity of VLS grown ITO nanowires using gold catalysts. In spite of the fact that the vapor pressure of tin is lower than that of indium, we found that the indium concentration within the nanowires was always higher than the nominal composition. The VLS growth of ITO through gold catalysts significantly differs from ITO film formations due to the emergence of preferential indium nucleation only at a liquid-solid interface. Furthermore, we demonstrate that the averaged resistivity of ITO nanowires can be decreased down to 2.1 × 10^-4 Ω cm, which is the lowest compared with values previously reported, via intentionally increasing the tin concentration within the nanowires.