NIRT: Dynamics of Structure and Charge at the Molecular Scale

University Of Maryland, College Park, College Park MD

Investigators

Abstract

This Nanoscale Interdisciplinary Research Team (NIRT) will focus on the effects of the discreteness of atomic structure and charge on the electronic properties of nanoscale devices. New tools will be developed to examine the structure and structure fluctuations of nanoscale devices while simultaneously measuring electronic transport properties. Specifically, nanoscale metal wires will be fabricated in situ in an ultra-high vacuum combined scanning-tunneling microscope/atomic-force microscope. The atomic-scale structural fluctuations of these wires will be studied during electromigration while simultaneously acquiring electronic transport information. Small gap junctions will be also be fabricated, and used to study simultaneously the atomic structure and electronic transport properties of carbon nanotubes and novel molecular devices. Concurrently, the sensitivity of nanoscale devices to fluctuating electrostatic environments will also be studied. New charge sensors such as carbon nanotube-based single-electron-transistors and semiconducting carbon nanotube field-effect transistors will be investigated. Efforts to manipulate the charge sensitivity of these devices through chemical modification will be explored. Undergraduate and graduate students will be involved in the development and use of cutting-edge research tools and will receive excellent training in interdisciplinary research at the frontiers of nanotechnology. %%% This Nanoscale Interdisciplinary Research Team (NIRT) is attacking two fundamental and intertwined problems, which will increase in importance, as electronic device dimensions become smaller. First, the discreteness of atomic matter becomes significant in determining structural stability of devices. Will fundamental properties such as the bonds between molecules remain stable during device operation. Second, the discreteness of charge causes significant sensitivity of the device to fluctuations in the electrostatic environment. How will local electric fields or static charge affect the devices. The quantum nature of electronic transport in nanoscale systems requires that the structure of molecular-scale devices - as well as their interconnects - be controlled at the atomic level. Techniques will be developed to simultaneously image the atomic structure of molecules, nanotubes, nanoscale wires, and interconnects while measuring electronic transport properties. Changes in the local electrostatic environment at the level of motion of single charges will have pronounced effects on the electronic transport through nanodevices. The proposed research will focus on the charge sensitivity of nanostructures ranging from superconducting single-electron transistors coupled to nanowires to semiconducting carbon nanotubes. Undergraduate and graduate students will be involved in the development and use of cutting-edge research tools and will receive excellent training in interdisciplinary research at the frontiers of nanotechnology.