AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Wednesday Sessions
       Session NS-WeA

Paper NS-WeA4
Direct Deposition of Molecular Electronics Materials using Thermal DPN

Wednesday, November 2, 2005, 3:00 pm, Room 210

Session: Nanopatterning and Manipulation
Presenter: P.E. Sheehan, Naval Research Laboratory
Authors: P.E. Sheehan, Naval Research Laboratory
M. Yang, Naval Research Laboratory
A.R. Laracuente, Naval Research Laboratory
B.A. Nelson, Georgia Tech
W.P. King, Georgia Tech
L.J. Whitman, Naval Research Laboratory
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We have developed a new technique, called thermal DPN (tDPN),@footnote 1@ where a heated atomic force microscope cantilever controls the deposition of a solid "ink." The heated cantilever can be used like a nanoscale "soldering iron" or "glue gun" to deposit semiconductors, insulators, or metals. tDPN has several advantages over conventional DPN. Control over writing is much greater--deposition may be turned on or off and the deposition rate changed without breaking contact with the surface. In addition, imaging with a cool tip does not appear to contaminate the surface, thereby allowing in situ confirmation of the deposited pattern. tDPN also expands the range of useable inks to those that are immobile at room temperature. Finally, multi-layer films can be deposited sequentially, enabling 3-D structures and heterostructures to be written directly. One material that is easily deposited by tDPN but which is challenging by other means is poly(3-dodecylthiophene), or PDDT. PDDT is a conducting polymer that shows great promise as an active component in organic electronic devices. Using tDPN, well-ordered PDDT nanostructures have been deposited on silicon oxide and gold surfaces with layer-by-layer thickness control. By adjusting the tip heating power and the writing speed, we can vary the polymer thickness from a single monolayer (~2.6 nm) to tens of monolayers with lateral dimensions below 100 nm. Unlike conventional DPN inks, this low vapor pressure polymer may be deposited in UHV by tDPN, thereby allowing integration with CMOS processing. Along with our success at depositing metallic indium nanowires via tDPN, we now have all the requisite elements for the direct deposition of electronic circuitry. @FootnoteText@ @footnote 1@ P. E. Sheehan, L. J. Whitman, W. P. King, B. A. Nelson, Appl. Phys. Lett. 85, 1589 (2004).