Transport, Analyte Detection, and Opto-Electronic Response of p-Type CuO Nanowires

In this article, we introduce and provide details on a large-scale, cost-effective pathway to fabricating ultrahigh dense CuO nanowire arrays by thermal oxidation of Cu substrates in oxygen ambient. The CuO nanowires that are produced at similar to 500 degrees C for similar to 150 min feature an average length and diameter of similar to 15 mu m and similar to 200 nm, respectively. The room temperature device-related characteristics such as transport, analyte detection and opto-electronic response of individual CuO nanowires have been probed by fabricating single CuO nanowire devices with the use of lift-off photolithographical techniques. The experiments confirm that as-grown nanowires are of p-type, have a band gap of similar to 1.4 eV, and show strong sensitivity to both NO2 and NH3 gases. The devices also showed strong response to white light with device responsivity approaching similar to 8 A/W for optical power densities of only similar to 1 mW/cm(2). Additionally, a complex interaction of photoproduced electron-hole pairs with the surface-originating chemisorbed agents including O-2 and NO, is found to drastically affect the gas sensitivity of CuO nanowire-based devices, where photoinduced adsorption of the analyte enhances the device response.