Dispersion Of Gold Nanorods On Au(111) And Preliminary STM Induced Luminescence Studies

Noble metal nanoparticles have attracted a lot of attention because of their unique optical properties associated with the surface plasmon resonance. When a fluorescent molecule or a DNA molecule is in the vicinity of a metal nanoparticle, its fluorescence intensity and spectral shape would be greatly modified by the surface plasmon of the metal nanostructure. If one can control the surface plasmon resonance, one will be able to modulate molecular luminescence, optical transitions and related energy transfer process. This is the major motive for the present work. To such end, one way we can do is to disperse the metal nanostructures on metal surfaces, and then explore their optical properties using scanning tunneling microscope (STM) induced luminescence technique.The present research focuses on the tuning of surface plasmon resonance of Au metal nanostructures through the control of size, shape, and coating agents. These gold nanostructures are then dispersed onto the Au(111) surface, and sputtering cleaned in vacuum to remove the coating agents, and finally characterized by the STM induced luminescence technique. This dissertation is mainly composed of three parts:1. Synthesis of Au nanorods with different sizes and aspect ratios in the aqueous solution, followed by the measurement of their optical properties and the calculation of surface plasmon resonance spectral shape via the Mie theory.2. Dispersion of Au nanorods on Au(111) with 16-mercaptohexadecanoic molecules as a spacer layer, followed by the cleaning of spacer molecules by ion sputtering process.3. Topographic Imaging of dispersed Au nanorods on Au(111) by SEM and STM and preliminary STM induced luminescence studies of Au nanorods.