CAREER: An Integrated Approach to the Control of Nanoscale Electronic Properties

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

The research objective of this grant is to understand and exploit the consequences of high surface to volume ratios in nanoscale systems, such as carbon nanotubes. Because of their high surface to volume ratio, the local chemical environment has a large impact on single wall nanotube properties. Self-assembled monolayers will be used as chemically adjustable surfaces on which to lay carbon nanotubes. Controlling the surface chemistry will allow control of semiconducting nanotube resistance and doping. Surfaces will be patterned with different chemistries at different locations. Nanotubes stretched across the boundaries of these regions will have patterned doping, leading to the formation of controlled nanotube devices. If successful, these experiments offer the potential for large-scale nanotube device fabrication. In addition to such potential applications, it is scientifically important to understand how local chemical environments affect nanotube resistances. Closely related experiments will study nanocrystal arrays. The consequences of local variations in the electronic environment of the array will be understood and exploited to control the array properties. The goal of both these groups of experiments is to better control the properties of nanoscale materials, using an integrated view of the ultra-small material and its surrounding environment. The educational objective of this project is to increase the number of women who pursue science past high school. The transition from high school to college has been identified as a time when students' needs can be better addressed. In particular, mentor-type interactions will be used to better explain the importance of, and the opportunity offered by beginning a science curriculum early in the undergraduate years. A program to enable these interactions will be developed which leverages existing outreach in order to better serve high school juniors and seniors. The program will provide practical career information through both personal contact and web-based interactions. %%% The research objective of this grant is to better control the electrical properties of carbon nanotubes. Nanotubes will be placed on surfaces with well controlled chemical properties. We will use the interaction of the nanotube with the surface to control the nanotube resistance. Changes in the surface chemistry will be used to change the nanotube properties. By creating patterns of different surface chemistry, we will create patterned electrical properties in nanotubes placed on these surfaces. If successful, this patterning will enable a new method to create transistors in nanotubes. This new process has the potential to produce a higher density of transistors than currently possible. It is also a step towards a solution to the problem of connecting many ultra-small transistors together - the interconnect problem. In closely related experiments, we will study the effect of the local electrical environment on nanometer-size crystals of metal. As is the case with the nanotube experiments just described, the goal of these nanocrystal experiments is to better understand how to control the electrical properties of nanometer-scale materials, using an integrated view of the ultra-small electrical device and its surrounding environment. The educational objective of this project is to increase the number of women who pursue science past high school. The transition from high school to college has been identified as a time when students' needs can be better addressed. In particular, mentor-type interactions will be used to better explain the importance of, and the opportunity offered by beginning a science curriculum early in the undergraduate years. A program to enable these interactions will be developed which leverages existing outreach in order to better serve high school juniors and seniors. The program will provide practical career information through both personal contact and web-based interactions. ***