Fabrication, Characterization, and Applications of Porous Silicon Metal-Oxide Nanocomposites

Abstract

Anodically etched porous silicon, which is characterized by aligned cylindrical pores in a silicon matrix, is an attractive material for applications in optics, energy, electronics, sensing, and biology. The porous silicon formation process allows for a high degree of control over the pore diameter and length, both of which can be tailored from the nanometer to micron scale. Functionalization of the pores with additional active materials provides the opportunity to further extend the capabilities and potential applications of porous silicon films. In this dissertation, I present my investigations of a nanocomposite materials system composed of porous silicon and transition metal oxides – nickel oxide and titanium dioxide. Fabrication is carried out based on thermal decomposition of the metal oxide precursor in a porous silicon film. The dependence of the physical properties of the nanocomposites on preparation conditions is characterized in detail. Promising applications of the nanocomposites for templated nanoparticle synthesis, variable conductivity, and electrochemical energy-storage are explored through rigorous experiments and analysis. In these studies, the porous silicon film not only provides a high surface area template for the growth of metal oxide nanoparticles, but also facilitates the opportunity to develop on-chip silicon integrated devices leveraging the properties of the metal oxide nanoparticles.