A Development of Gold Nanodots Fabrication for Optical Plasmonic Applications

Optical plasmonic sensing is an up-and-coming technique for label-free biosensing, particularly in detecting antigen-antibody binding. This research introduces an efficient nanofabrication method, employing the self-organization approach of thermal annealing to create gold nanodots on a quartz substrate. Fabrication involved careful sputter depositing and thermal annealing procedures to achieve optimal results. A 24 full-factorial design was implemented to assess the average diameter of gold nanodots. The investigation focused on evaluating the impact of varying parameters, including the thickness of the gold film on the quartz substrate, annealing temperature, annealing time, and chemical treatment applied to the surface of the quartz substrate. Statistical analysis considering the main effects and mixed interactions between factors revealed that the chemical treatment on the quartz substrate's surface emerged as the most influential parameter in determining the gold nanodot characteristics. Significantly, the results underscored an optimum thermal annealing condition for gold nanodot aggregation, characterized by a thickness of the gold film of 30 nm, annealing temperature of 700°C, and annealing time of 30 minutes, along with surface treatment on the quartz substrate. Validated at a significant level of 95%, these findings provide valuable insights for refining and optimizing the nanofabrication process, contributing to advancing plasmonic biosensing applications.