Realization of adhesion enhancement of CuO nanowires growth on copper substrate by laser texturing

Abstract

CuO nanowires (NWs) are easily grown by thermal oxidation, but the practical applications have been restricted due to the cracking of CuO NWs films or exfoliation from the copper substrate. In this paper, laser texturing combined with thermal oxidation to synthesize CuO NWs demonstrates that the two-step approach is beneficial to the growth and adhesion enhancement of CuO NWs on the copper substrate. Laser texturing at different laser scan times and scan spacing forms micro-patterned grids on the copper sheet, followed by the thermal oxidation growth of CuO NWs on the laser textured copper sheet. The adhesion of CuO NWs on the copper substrate is evaluated by tape test and ultrasound test. The cross-sectional SEM images of the CuO NWs sample and the element concentrations at different layers indicate that the growth mechanism of CuO NWs conforms to the stress-driven grain-boundary diffusion model. The analysis shows that the formed micro-patterned grids by laser texturing provide additional contact area for copper and thermally activated oxygen. In addition, it contributes to thermal stress release at the edges of micro-grids, which is capable to protect the oxide layer from exfoliation. Therefore, the proposed approach has proved to be effective to adhesion enhancement of CuO NWs on the copper substrate, which is of great significance for promoting and extending the potential applications of CuO NWs in various functional surfaces and devices.