Optimization of Ag/Si Schottky Device: Enhancing Temperature Sensitivity by Silver Nanostructure Morphology for Surface Plasmon Resonance Enhancement

This study investigates the effects of modifying the surface nanostructure at the metal-semiconductor interface of a thin Ag/Si Schottky device. The results show that thermal annealing provides metal atoms with sufficient energy to rearrange, leading to the formation of a nano-island structure in the metal thin film. In this work, low-temperature annealing at 150–250°C was applied to slightly increase the size of silver nanoparticles. Compared to the morphology of the unannealed silver thin film, the surface light intensity was enhanced from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$8.496 \mu \mathrm{W} / \mathrm{m}^{2}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2243.48 \mu \mathrm{W} / \mathrm{m}^{2}$</tex>, an increase of approximately 264 times. Properly sized silver nanoparticles enhance the localized surface plasmon resonance (LSPR) effect, strengthening incident light absorption and the optical field enhancement effect, thereby improving photoelectric and photothermal conversion efficiency. With proper nanomorphology for the local field enhancement, the device could be used to successfully measured the human body temperature range of 35–42°C with a step increment of 0.2°C.