Ethanol gas and humidity sensors of CuO/Cu2O composite nanowires based on a Cu through-silicon via approach

High density CuO/Cu2O composite nanowires were synthesized on simpler Cu through-silicon via by heated oxidation. XRD spectrum analysis and HR-TEM revealed that these nanowires had Cu2O cubic crystalline and CuO monoclinic structures. The sensing current of the CuO/Cu2O composite nanowires decreased as the ethanol concentration increased due to their p-type material property. The relative humidity response of the nanowires increased along with the relative humidity. The UV photoresponse of the CuO/Cu2O composite nanowires also increased with the relative humidity, due to the photocatalytic layer that formed on the nanowire surface.