Highly sensitive double-layered nanorod array gas sensors prepared by oblique angle deposition

ITO based nanorod arrays fabricated by oblique angle deposition (OAD) were designed as resistive gas sensors for NO2 detection, and the detection limit was found to reach as low as 50 ppb with a response time of 20 min. A comparative study shows that the ITO nanorod array has a higher sensing response than that of the ITO film, and a double-layered ITO nanorod array design could further improve the sensing response. By increasing the vapor incident angle during the nanorod fabrication, the sensing response also increases, due to the increased porosity and gas penetration. It is expected that OAD technique could become a versatile and scalable fabrication technique for gas sensors. (C) 2014 AIP Publishing LLC.