CuO nanowires grown from Cu film heated under a N2/O2 flow

Pure, large-area, and aligned CuO nanowires are realized from copper thin film deposited onto silicon substrate by thermal annealing under a N2/O2 gas flow. The as-prepared pure and vertically aligned CuO nanowires along silicon substrate have several advantages over previous approaches such as easier integration into silicon based micro systems, more convenience for subsequent elements deposition, and higher heat of reaction for realization of CuO/Al based nano energetic materials. It is found that long and aligned nanowires can only be formed within a narrow temperature range from 400 to 500 degrees C. A N2/O2 gas flow rate of 400/100 sccm is moderate for realizing long and aligned CuO nanowires. The synthesized nanowires and thin film beneath the nanowires are confirmed to be pure CuO using X-ray diffraction. The CuO nanowires are found to be bicrystal by high resolution transmission electron microscopy.