10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Surface Enhanced Raman Scattering of Silicon Quantum Dots Generated by Laser Ablation
Eisuke Okuchi, TAKAFUMI SETO, Mohamed Abd El-Aal, Makoto Hirasawa, Kanazawa University
Abstract Number: 437 Working Group: Materials Synthesis
Abstract Silicon quantum dots (Si-QDs, 4 to 12 nm) were fabricated by laser ablation under the helium background gas. Size distribution and the crystallinity of the Si-QDs were controlled by the low pressure differential mobility analyzer (LP-DMA) and the aerosol post annealing process (room temperature to 1273K), respectively. These Si-QDs were deposited on the Cu substrates coated by Ag nanostructure. Raman signal was observed from SiQDs using exciting laser with wavelength of 532nm and power of 0.5 mW with changing the size and annealing temperature (crystal structure) of the Si-QDs. Strongly enhanced Raman signal of Si peak (enhancement factor >10 hold) was observed from the sample prepared by gas phase annealing around the transition temperature of Si crystallization. The enhancement factor decrease with increasing annealing temperature, suggesting a weak interaction between excitation laser (532nm) and nanocrystalline Si (>4nm). The results suggest that the overlapping between the plasmon electric field and the bandgap of Si-QDs might be triggered in the ultrafine silicon nanocrystallines less than 4nm.