Isopropyl Alcohol Sensors of CuO Nanotubes by Thermal Oxidation of Copper Films on Glass

The growth of CuO nanotubes on Cu/CuO/glass templates is reported. It was found that porous structures were formed at the interface between sputtered CuO film and Cu layer after annealing. The average length of the nanotubes and thickness of the porous structure both increased monotonically as we increased the initial thickness of the copper film. The CuO nanotubes were used to fabricate isopropyl alcohol (IPA) sensors. With a 5-V applied bias, the current became smaller as the IPA was injected into the sealed test chamber. Furthermore, the measured response was larger for the sensors with longer CuO nanotubes.