An investigation of the nanogranular Au films electrolessly deposited on Si surfaces

Abstract

The thesis titled 'An investigation of the nanogranular Au films electrolessly deposited on Si surfaces' presents the efforts made to exploit the method of electroless deposition in nanostructuring gold. Chapter 1 contains a brief overview on the methods employed for nanocrystalline metal films with special emphasis on the electroless process. A systematic study carried out to obtain epitaxial Au films on Si(lll) surfaces ha s been discussed in Chapter 2. It explains the effect of variation in plating conditions such as concentration of the plating solution, deposition time and bath temperature, on the crystallographic orientation and morphology of the deposited films. Chapter 3 describes the formation of discrete nanostructures of Au by controlling the metal growth using surfactant molecules or by masking selected regions of the Si substrate. The effect of surfactants such as poly(vlnylpyrrolidone) and mercaptoundecanoic acid as additives in the plating solution, ha s been studied. Alternatively, self assembling molecules such as silanes have been used as masking agents to form discrete nanostructures of Au. Chapter 4 deals with electroless deposition of Au on Si substrates precoated with carbon. The morphology of the nanogranular film ha s been investigated as a function of the underlying carbon layer thickness. The chemical nature of the Au deposits inside the carbon pores is also examined. This chapter also describes the utility of the prepared nanogranular films as substrates for Surface Enhanced Raman Scattering (SERS) from organic as well as biomolecules.