Production and characterization of nanocomposite thin films based on Ni matrix reinforced with SnO2 single-crystalline nanowires for electrical contact applications

• Metal-matrix nanocomposites obtained, reinforced by nanowires attached to substrate.
• Nanocrystalline matrix in spite of direct-current electrodeposition being used.
• Strong influence of SnO2 nanowires on surface and microstructural properties.
• Previous coating of nanowires (with Ag) improved the matrix deposition.

Nanocomposite thin films based on electrodeposited Ni matrix reinforced with SnO2 single-crystalline nanowires grown onto Si substrates by chemical vapor deposition were produced. The composites were characterized by means of scanning and transmission electron microscopy (for imaging, selected area diffraction and transmission Kikuchi diffraction), atomic force microscopy (for 3D surface profiling and roughness evaluation) and 4-point probe electrical resistivity measurements. The Ni matrices obtained were nanocrystalline in nature (41 nm crystallite mean size) even though low direct current electrodeposition was used. The topography and roughness of the samples were strongly affected by the presence of the nanowires as so was the electrical resistivity, which could be improved by Ag-coating the nanowires. A comparison with pure Ni produced in the same way is presented for determining the effects of the SnO2 nanowires.