Abstract
Metallic nanodot array is attracting attention for biosensors attributed to the localized surface plasmon resonance (LSPR). In this paper, ordered metallic (gold and silver) nanodot arrays are fabricated by combination of Nano Plastic Forming and annealing process. The LSPR properties of the fabricated metallic nanodot arrays are investigated by measuring the extinction spectra. Effects of morphology of a nanodot array on the LSPR properties are studied. Sensitivity of LSPR peak wavelength against refractive index of the dot surrounding medium is investigated. It is found that the ordered nanodot array exhibits much sharper spectra peak than the random nanodots. The extinction spectra are affected by the size and the shape of the nanodot. The sensitivity of LSPR sensor increases with the increase of dot diameter. The highest sensitivity obtained in this experiment is 208nm/RIU by using a gold nanodot array with average diameter of 196nm. Furthermore, an analytical model based on Kuwata's theory is used to investigate the plasmonic properties of the metallic nanodot. The theoretical results show good agreement with the experimental data. In addition, the possibility for LSPR sensor with higher sensitivity is discussed and predicted by using this model.
