| 초록 |
Metallic nanogaps that are typically as small as few nanometers enable to strongly concentrate an incoming light into such small space, resulting in a strong near-field enhancement. This excellent optical property has been exploited to increase weak molecular signals such as Raman and fluorescence. However, most of previous methods rely on sophisticated lithographic techniques and it is very difficult to fabricate high-density nanogaps by using colloidal nanoparticles. Here we propose simple and facile method to producing high-density nanogaps. Our proposed method consists of two steps; (1) sequential deposition of gold and silica thin film on various substrates (e.g., glass, PDMS) followed by (2) transfer of colloidal nanoparticles monolayer onto the substrates. The resulting substrate shows many nanogaps that are originated from (1) between colloidal nanoparticles and (2) between colloidal nanoparticle and gold thin film, respectively. The physical properties of as-made substrates are well characterized by scanning electron microscope (SEM) and UV-vis spectrometer. Our substrates are also applied to sensitive molecular detection via surface-enhanced Raman spectroscopy. |
