CAREER: Molecular Scale Electronic Devices and Systems

University Of Southern California, Los Angeles CA

Investigators

Abstract

The relentless down-scaling of the conventional metal-oxide-semiconductor (MOS) based integrated circuits is expected to slow down due to fundamental physical limitations and increasingly prohibitive cost associated with fabrication facilities. Molecular electronics, where the idea is that only a few or even just one molecule could be used to perform basic electronic functions, holds great promises for superior performance and substantially reduced cost. As a bottom-up approach to fabricate nanostructures, molecular electronics employs chemical synthesis and assembly to produce devices with critical dimensions defined by the molecular wires and hence can eliminate the cost associated with advanced lithography techniques. Such devices utilize various quantum effects such as tunneling and conformational transitions to their advantages and thus can deliver better performances than conventional MOS devices. The eventual success of this program will firmly establish molecular electronics as an intriguing and practical technology with great potential to replace silicon-based electronics. We expect to produce the molecular electronics version of two core elements in integrated circuits: transistors and memories. Our molecular transistors will possess a channel length around two nanometers, two orders of magnitude smaller than that of today's most advanced silicon-based transistors. We also expect to demonstrate nonvolatile spin-dependent memories with molecular wires as the active component. This technique will likely produce ultra-small memory devices and add a new direction to the by far "classical" molecular electronics. Finally we expect to demonstrate a new scheme for integrated molecular systems with carbon nanotubes as interconnects. This program will also serve to advance the fundamental forefronts of molecular electronics. Several unique features distinguish this program from other existing programs in this field. 1. We will utilize the nanopore technique to produce molecular transistors and spin-electronic devices. Our group is one of two existing groups that have mastered this technique (the other being the Mark A. reed group at Yale, who is currently focusing on two-terminal nanopore devices). This technique can render devices with channel length defined by the molecular wire length (~ 2 nm) and device areas ~ 10 nm in diameter. Such nanoscale devices hold great promises for high-density integrations. 2. We will investigate both n-type and p-type molecular wires in our transistor structures, making complementary circuitry possible. This important issue has by far being unexplored by other research groups due to the apparent difficulty. 3. An intimate integration of the proposed research and education is guaranteed. Substantial effort will be devoted to educate both graduate and undergraduate students, especially the underrepresented, throughout this program. The research activities will also be integrated into the Nanoelectronics and Nanotechnology class I developed. 4. We enjoy full support from our collaborators at the Nanotechnology Center of NASA Ames Research Center. Dr. Wendy Fan and her colleagues are currently devoting 100% of her time to the organic synthesis component of this program, at no cost to NSF. Dr. Jie Han is focusing on the theoretical modeling and simulations of the proposed molecular devices, again, at no cost to NSF. In conclusion, the proposed program holds great promises for future nanoscale electronics and has a great chance to succeed. The financial support from NSF can be invaluable in helping me to achieve my goal to develop a life-long career in scientific research, academic advising and teaching.