Transfer of silicon nanowires onto alien substrates by controlling direction of metal-assisted etching

Si nanowires (SiNWs) are promising materials for future electronic, photovoltaic, and sensor applications. To date the SiNWs are mainly formed on particular substrates or at high temperatures, greatly limiting their application flexibility. Here we report a low temperature process for forming and massively transferring vertically aligned SiNWs on alien substrates. Metal-assisted etching method was used to fabricate vertically aligned SiNWs on Si substrates. To detach SiNWs from Si substrates, the roots of the Si NWs were etched and became fragile by controlling direction of metal-assisted etching. Thus, every SiNW on the Si substrate can be easily transferred to alien substrates. Because of the low temperature process, it enables a large variety of alien substrates such as glass and plastics to be used.