Silicon carbide nanowires and nanospings: processing, self-assembly, characterization, and propertie
EMSL Project ID
3444
Abstract
One-dimensional nanowires are increasingly attracting attention in scientific and technological communities because of their versatile novel electrical, optical and mechanical properties. Their potential applications range from tips in scanning probe microscopes to interconnections in nanoelectronical devices, as well as utilization of their field emission properties in flat-panel displays. Silicon carbide is a particular attractive material for these applications because of its high thermal and electric conductivity, and outstanding mechanical properties. This research program can be divided into three primary goals. The first goal of this program is to study the dependence of nanowire growth and structure on various processing variables. For helical nanowires—nanosprings, we focus on developing a fundamental understanding of the mechanisms driving nanospring formation, with the ultimate objective of controlling their physical dimensions and properties. The initial, intermediate, and final stages of the growth of the silicon carbide nanowires will be explored using both scanning and transmission electron microscopy. With this approach it will be possible to obtain a detailed understanding of the growth process and develop well-defined methods for growing silicon carbide nanowires of specific geometries. In addition to studying the growth process, a technique will be developed for the self-assembly of the silicon carbide nanowires. Through the use of catalyst Fe, Ni and Pt eutectic seeding of the substrate, either by the use of nanolithography or naturally occurring porous membranes, self-assembled silicon carbide nanowires will be growth. Initial studies have been promising and suggest that catalyst seeding of the substrate is a viable option.
The second goal is to explore the fundamental properties of nanowire as a function of structures, nanospring as a function of their physical dimensions and materials composition (such as SiC, BC, GaN, etc.) in order to evaluate the validity of traditional macroscopic models of the springs at the nanoscale. Using nanoindentation and scanning probe microscopy or atomic force microscopy, the strength and resiliency of silicon carbide nanowires as a function of wire morphological structure will be evaluated. In addition, the fundamental structure and elastic properties of the silicon carbide nanowires will be determined.
The third goal of this program is to examine the electric properties of silicon carbide nanowires. Since silicon carbide is a wide band gap semiconductor (~3.0eV). The reduced dimensionality of the nanowires should result in novel quantum confinement effects. By varying the diameter of the nanowires, an excellent opportunity exists to study size dependent effects on quantum confinement. The dependence of their electronic properties as a function of temperature, wire diameter, wire length, and wire geometry will be examined. The results of these studies will not only help to determine the feasibility of using silicon carbide nanowires in composites, but will also provide a database for future work.
Project Details
Project type
Exploratory Research
Start Date
2003-04-01
End Date
2006-04-02
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members