Molecular Transistors

Energy Sciences Institute Talks - West Campus

Mark Reed
Harold Hodgkinson Professor of Engineering & Applied Science and Applied Physics

Molecular Transistors

January 7, 2015
3:00 pm
Conference Center West Campus - Room 208

Mark A. Reed¹, Hyunwook Song, Hyunwook^1,2; and Takhee Lee^3
1Yale University, New Haven, CT, USA; ²Kyunghee University, Yongin, Korea; ³Seoul National University, Seoul, Korea

Electron devices containing molecules as the active region have been an active area of research over the last few years. In molecular-scale devices, a longstanding challenge has been to create a true three-terminal device; e.g., one that operates by modifying the internal energy structure of the molecule, analogous to conventional FETs. Here we report¹ the observation of such a solid-state molecular device, in which transport current is directly modulated by an external gate voltage. We have realized a molecular transistor made from the prototype molecular junction, benzene dithiol, and have used a combination of spectroscopies to determine the internal energetic structure of the molecular junction, and demonstrate coherent transport.^2,3 Resonance-enhanced coupling to the nearest molecular orbital is revealed by electron tunneling spectroscopy, demonstrating for the first time direct molecular orbital gating in a molecular electronic device.

We further demonstrate that energetic orbital positions can be modified by appropriate endgroup and sidegroup substitutions. Modifications of endgroups allows the realization of complementary single molecule FET devices. Systematic sidegroup substitutions of varying electronegativity allows a systematic engineering of orbital positions, analogous to threshold voltage control. The unique device characteristics that these types of molecular devices enable will be discussed.

¹ H. Song et al., Nature 462, 1039 (2009)
² H. Song et al., J. Appl. Phys. 109, 102419 (2011)
³ H. Song et al., J. Phys. Chem. C, 114, 20431 (2010)

Contact: amy.cacciamani@yale.edu