Controlled formation of well-aligned GaAs nanowires with a high aspect ratio on transparent substrates

In this study, we present a facile way to fabricate large-scale arrays of GaAs nanowires (NWs) with a high aspect ratio on transparent substrates. It is demonstrated that a monolayer of SiO2 nanoparticles can be effectively used as etch masks for the inductively coupled plasma (ICP) etching process. To form the monolayer of SiO2 nanoparticles on a GaAs substrate, the concentration and temperature of a SiO2 colloidal dispersion solution as well as the interface wetting of the GaAs substrate were investigated. Afterward, by adjusting the ICP etching conditions, the high-aspect-ratio GaAs NWs with cross-sections of 70 nm and lengths of 4.3 µm were successfully fabricated. Furthermore, the fabricated GaAs NWs were massively transferred onto the transparent substrate at low temperature. The x-ray diffraction spectrum and the scanning electron microscope observation reveal that the transferred GaAs NWs have vertically aligned morphology and good crystal property