GOALI: High Field Transport and Device Modeling of Carbon Nanotube Structures

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

Over the past several decades scaling of MOS transistor technology to smaller dimensions has given rise to a rapid increase in integrated circuit performance. It is however well recognized that continued scaling is limited by quantum phenomena that dominate the characteristics of devices on the nanometer scale, even if the escalating investments can be absorbed successfully. As an eventual alternative to scaling MOS technology, research is directed at new devices and new operational paradigms that are tied to quantum phenomena on the one hand and to nanotechnology on the other. Many parallel paths towards a technology of molecular electronics are being explored. Among the most promising structures in this context are so-called carbon nanotubes (CNTs). The focus of this proposed program is a study of high-field, high-temperature charge carrier transport in CNTs and, building on these results, the formulation and analysis of device models, specifically for CNT-based field effect transistors (CNT-FETs). It is planned to adapt and apply a new Monte Carlo technique that was developed under previous NSF funding. In that earlier work the traditional Monte Carlo paradigm of semiclassical transport theory was generalized to allow for interband tunneling transitions. It is also planned to construct semianalytical CNT-FET models that are suitable for an exploration of realistic device operating conditions. The intellectual merit of the proposed activity includes the advancement of the understanding of high-field charge carrier transport. CNTs are well suited as an example material with the desired flexibility because of the strong dependence of their electronic structure on the tube geometry. This will allow for a direct correlation of bandstructure to transport without adding the complication of having to compare results for chemically different materials. Furthermore, CNT-based devices are excellent candidates for future nanometer scale electronics applications and the proposed program can make significant contributions to a quantitative assessment of these prospects. To ensure that the calculations have maximum relevance for experimental exploration the research will be conducted in close interaction with Dr. Phaedon Avouris and his group at IBM's T.J. Watson Research Center. The proposed program has broader educational impact through the involvement of graduate and undergraduate students in the exciting fields of nano technology and in the collaboration with industrial partners. The lead graduate student at the University of Minnesota will serve as the point of contact for a researcher to be identified in the IBM group. This student will be responsible for accurate and timely exchange of information also between the University of Minnesota and Georgia Tech groups. It has been our experience that the direct involvement of students in this type of interaction gives them an opportunity to display initiative and to set up working relationships with industry that are potentially valuable for their future career. In addition, the PIs have a track record of incorporating their on-going research into classes, off-campus presentations to students, and textbooks. The educational aspect of their research therefore reaches an audience beyond their immediate research groups.