Effect of ambient pressure on the selective growth of square In2O3 nanowires

Single crystalline indium oxide (In2O3) nanowires (NWs), formed via a simple vapor transport route, were synthesized by a selective growth approach on patterned SiO2/Si substrates. The selective growth approach enabled us to have a more systematic analysis of the effects of the synthesizing parameters on the growth of the NWs. In this study, the ambient pressure in the quartz tube was controlled in the range of 250–1,000 mTorr, and the dependence of NW size and density was investigated. Statistical analyses demonstrate that the ambient pressure plays an important role in determining the nucleation and crystal growth of In2O3 NWs, thereby affects the diameter, length, and density of the NWs. Our result indicates that the interplay between the source export and the absorption import as well as the coalescence of catalyst droplets are mainly affected by ambient pressure in the quartz tube, which eventually contributes to the yield of NWs on catalytic substrates.