Fabrication and properties of Cu-Ni mixed-metal periodical array for midinfrared filtering and hydrophobic application

Abstract

Cu was grown successfully on Ni film as a conductive layer that demonstrated a stronger Cu (111) preferred crystallographic orientation. Furthermore, we studied the scale effect of various periods of patterned Ni lines separated by variable widths of SiO2. When Cu was electroplated onto this patterned Ni, it preferentially deposited on the Ni edges adjacent to the SiO2 stripes, resulting in a Cu-Ni-Cu-SiO2, Cu-SiO2-Cu, or Cu-Cu structure, depending on the dimensions of the starting Ni pattern and the deposition time. There are two reflective dips at 2.2 and 8 mu m wavelengths using Fourier transform infrared spectroscopy, which revealed a trend of narrower bandwidth in reflective spectra and a redshift effect with increasing deposition time. Interestingly, a hydrophobic surface was also observed due to its particular surface-roughness structures that could be controlled by the deposition time and altered the contact angle from 72 degrees to 110 degrees without coating any extra low free-energy materials. (C) 2008 American Vacuum Society.