Fabrication of the Pattern of Copper Nanowires with Adjustable Density on Oxidized Si Substrate

We report a method of combining of ultrathin liquid layer electrodeposition with chemical microetching, to fabricate the pattern of ultralong (L > 100 μm) copper nanowires with adjustable density on a two-dimensional oxidized Si substrate. In the electrodeposition process, we employ a periodic variation voltage in an ultrathin layer of concentrated CuSO4 electrolyte. The periodic nano/microstructures with alternate homogeneous membrane and ridgelike wire stripes are constructed by the electrochemical deposition. The pattern can be controlled by varying the frequency of the applied voltage. The homogeneous membrane stripes can be etched out to form the parallel copper wires pattern by the KHSO5/H2SO4 mixture solution. The KHSO5/H2SO4 etchant shows a good stability in microetching. The homogeneous membrane makes it easier to control the removal process using the chemical microetching. The density of wires can be adjusted by changing the frequency of applied voltage, and the large area pattern can be obtained. A suitable explanation has been given for the growth mechanism of periodic structures, and the mechanism of etching. This method is simple and controllable and can be applied to fabricate other metal patterns having potential applications in microelectronics and optoelectronics.