Foresight Nanotech Institute Logo

« Go Back

You are viewing
Foresight Archives

Image of nano

Silicon-Based Molecular Nanotechnology

Mark C. Hersam and Joseph W. Lyding*

Beckman Institute and Department of Electrical and Computer Engineering
University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA

This is an abstract for a presentation given at the
Seventh Foresight Conference on Molecular Nanotechnology.
The full article is available at


One potential application of molecular nanotechnology is the integration of molecular electronic function with advanced silicon technology. One step in this process is the tethering of individual molecules at specific locations on silicon surfaces. This paper re-ports the fabrication of arrays of individual organic molecules on H-passivated Si(100) surfaces patterned by UHV STM. Feedback controlled lithography (FCL) is combined with the hydrogen resist nanofabrication technique1 to create templates of individual silicon dan-gling bonds (see Fig.1). Molecules introduced in the gas phase then spontaneously assemble onto these atomic templates. Copper phthalocyanine (Cu(Pc)) and norbornadiene2 molecular arrays have been made by this technique and studied by STM imaging and spectroscopy. Cu(Pc) molecules appear as a four-fold dark depression surrounding a bright central spot in empty states images, whereas in filled states images they are nearly indistinguishable from Si dangling bonds. These experiments are now focussing on measuring and modifying (by STM) intramolecular electronic structure and probing intermolecular interactions, such as quenching molecular rotation3, by adjusting intermo-lecular spacing. Another aspect of this work is the development of a UHV-compatible nanoscale contacting scheme for probing individual molecules and ultimately contacting nanoscale molecular circuits. Initial experiments4 show that planar p-n junctions are compatible with the H-resist/molecular assembly methods while enabling large voltage drops to be applied across nanoscale dimensions.

Figure 1 GIF 80K

Fig. 1: Template of Si dangling bonds made by UHV STM hydrogen desorption. Inset shows two of the sites after adsorption of copper phthalocyanine molecules.


  1. J. W. Lyding, T.-C. Shen, J. S. Hubacek, J. R. Tucker, and G. C. Abeln, Appl. Phys. Lett. 64, 2010 (1994).
  2. J. W. Lyding, K. Hess, G. C. Abeln, D. S. Thompson, J. S. Moore, M. C. Hersam, E. T. Foley, J. Lee, Z. Chen, S. T. Hwang, H. Choi, Ph. Avouris, and I. C. Kizilyalli, Appl. Surf. Sci., 130-132, 221 (1998).
  3. J. K. Gimzewski, C. Joachim, R. R. Schlittler, V. Langlais, H. Tang, I. Johannsen, Science 281, 531 (1998).
  4. M. C. Hersam, G. C. Abeln, and J. W. Lyding, Microelectronic Engineering, in press (1999).

*Corresponding Address:
Joseph W. Lyding
Beckman Institute, University of Illinois
Urbana, IL 61801 USA
Phone: (217) 333-8370; Fax: (217) 244-1995
e-mail:; Web:


Foresight Programs


Home About Foresight Blog News & Events Roadmap About Nanotechnology Resources Facebook Contact Privacy Policy

Foresight materials on the Web are ©1986–2018 Foresight Institute. All rights reserved. Legal Notices.

Web site developed by Stephan Spencer and Netconcepts; maintained by James B. Lewis Enterprises.