Growth Mechanism of the Copper Oxide Nanowires from Copper Thin Films Deposited on CuO-Buffered Silicon Substrate

The growth mechanism of the CuO single-crystal nanowires (NWs) for future device applications has been demonstrated using the copper films deposited on CuO-buffered substrates. The mechanism involves a two-step process: In the first step, hillocks of copper are formed to relieve the compressive stress existing on the copper films at high temperature for a long duration of time in air and then phase is formed by the oxidation of the hillocks in air ambient. The second step involves a continuous supply of copper through the porous seed and then the transformation of the phase to CuO NW. The CuO NW was grown by a continuous supply of both copper from the copper films and oxygen from air. The indispensable requirements for CuO NW growth from the copper films are the presence of compressive stress in the copper films and the presence of the seed phase on the copper films at a high temperature in air.