Invited talk

IETS of single molecule transistors

M. A. Reed^1,2, H. Song^2,3, and T. Lee⁴

¹Department of Applied Physics, Yale University, USA

²Department of Electrical Engineering, Yale University, USA

³Department of Applied Physics, Kyung Hee University, South Korea

⁴Department of Physics, Seoul National University, South Korea

Electron devices containing molecules as the active region have been an lively 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 report [1] 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 (BDT), 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 inelastic electron tunneling spectroscopy (IETS), demonstrating for the first time direct molecular orbital gating in a molecular electronic device [1].

Figure 1: (a) Gate dependent IETS (4.2K) of a BDT transistor. The left-hand y axis corresponds to the grey shaded region, and the various right-hand y axes (with different scales) correspond to spectra in the non-shaded region. (b) Two dimensional color map of the gated IET spectra. (c) Persson-Baratoff resonantly enhanced IETS model of the ν(18a) mode.

[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)