Structural, electrical and optical studies of gold nanostructures formed by Ar plasma-assisted sputtering

Ultrathin gold layers with different thickness of (10–100 nm) on the glass substrate were obtained by Ar plasma-assisted sputtering. The effects of annealing on gold structures sputtered onto glass substrate were studied using AFM, SEM, UV–Vis methods and electrical measurements. Concentration of free charge carriers were determined from the measured resistance and the Hall constant measured by the Van der Pauw method. We have shown that post-deposition thermal treatment leads in significant change in surface morphology of the sputtered Au structures. Our results suggest that the annealing affects electrical properties of the Au coverage namely electrical sheet resistance, free carriers volume concentration, the saturation of which is in comparison with as-sputtered samples shifted towards thicker structures. While semi-conductive character of as-sputtered samples diminishes close to the Au structure thickness of ca 20 nm, in the case of the annealed structures zero-level saturation is achieved for the thickness of 60 nm.