Electrical and thermal transport in silicon nanowires

Nanowires have emerged as promising components for future electronic and energy conversion devices, but many of their unique properties are poorly understood. Specifically, nanowires are natural conduction channels which behave in new and different ways than their corresponding bulk material. The potential parameter space of useful properties in these materials is encouraging in its breadth, but as of yet the field lacks predictive models for many of their transport phenomena. While new material behavior is being discovered regularly, a fundamental understanding of the relationship between synthetic methods, structure, and properties of nanowires will aid design of functional materials for future technologies.;The following collection of research comprises novel methods for controlled nanowire fabrication, the investigation of basic transport properties, and the implementation of functional nanowires in solid state devices. Synthetic techniques have progressed to the point where nanowires can be synthesized with a wide variety of compositions and heterostructures. These nanowires can be grown directly on epitaxial or heteroepitaxial device-ready substrates for ease of integration and control over crystal growth direction-dependent properties. Alternatively, nanowires can be synthesized or dispersed on inexpensive and flexible substrates for scalable and novel device structures. These chemical routes provide a deterministic method for fabricating one-dimensional nanostructures with desired electrical, thermal, and optical properties.;The ability to synthesize well-defined, single crystalline nanowires facilitates the discovery and measurement of novel materials properties. Due to their extensive surface area, many nanowire properties are dominated by their interfaces. A bottom-up synthetic approach to semiconductor component fabrication imparts precise control over these interfaces. For electronic applications, nanowire interfaces can be tailored to optimize electron transport. For example, nanowire field-effect transistors, which form the basis for many logic circuits, switch on and off with remarkable efficiency. For thermoelectric applications, on the other hand, these interfaces can be roughened to selectively impede thermal transport. These examples, and others, will be presented in the following manuscript to describe how deterministic nanowire synthesis can be used to study various aspects of transport phenomena in Si one-dimensional systems.