Formation of Sphere-like Au Nanoparticles on Substrate with Laser Illumination and Their Surface Plasmon Behaviors

摘要

Fabrication of sphere-like Au nanoparticles (NPs) of fixed orientation on sapphire, GaN, and SiO2 substrates through the irradiation of a few pulses of 266-nm laser onto Au thin films deposited on the substrates was demonstrated. Numerical simulations based on the finite-element method using the experimental parameters show highly consistent localized surface plasmon resonance spectral positions and their variation trends. From the simulation results, one can also observe the relative importance between NP absorption and scattering in contributing to the extinction. This simple laser-irradiation method for fabricating fixed-orientation sphere-like Au NPs of no aggregation and of strong adhesion to the substrate is useful for developing polarization- sensitive LSPR bio-sensing. In addition, helical deposition of InGaN with a quasi-periodical indium content distribution along the growth direction for growing InGaN nanoneedles with the vapor-liquid-solid growth mode by using Au nanoparticles, which are formed on a GaN template with pulsed laser irradiation, as catalyst in a metalorganic chemical vapor deposition reactor is deduced.