Development of gold thin-film for optical-based biosensor

The localized surface plasmon resonance phenomenon of gold (Au) nanostructured in thin film form has many attractiveness for optical based sensing applications. Plasmon resonance robustly influences optical properties the Au thin film. Therefore, the optical response of Au thin film determined by nanostructure of Au nanoparticles on the surface of substrate. However, the thermal annealing strongly affects to the nanostructure Au thin film. In this study, low-cost Au thin film has been developed by vacuum thermal evaporation technique and thermal annealing process. The thermal annealing was applied in certain temperature 400 ⁰C with various annealing durations were applied to generate Au thin films. The effect of thermal annealing on nanostructure and optical properties of Au thin films were measured. The statistical quantities of the average height value of grain particles was between 13 to 21 nm and the density was between 100 to 200 particles per square micrometer after annealing. The optical properties of gold thin-film in terms to be applied as sensor in optical-based biosensor reported. The best of RIS sensitivity obtained above 90 nm RIU-1. The results appearance a great promising for sensor applications.