AVS 52nd International Symposium
    Nanometer-Scale Science and Technology Monday Sessions
       Session NS1-MoM

Paper NS1-MoM2
Characterization of Polymer Nanostructures Deposited with Thermal DPN

Monday, October 31, 2005, 8:40 am, Room 204

Session: Nanometer Scale Structures
Presenter: A.R. Laracuente, Naval Research Laboratory
Authors: A.R. Laracuente, Naval Research Laboratory
M. Yang, Naval Research Laboratory
P.E. Sheehan, Naval Research Laboratory
W.P. King, Georgia Institute of Technology
L.J. Whitman, Naval Research Laboratory
Correspondent: Click to Email
We have developed a new variant of dip-pen nanolithography (DPN) called thermal DPN (tDPN),@footnote 1@ where a heated atomic force microscope cantilever controls the deposition of a solid "ink." Using this technique we have successfully deposited semiconductors, insulators, and metals, and extended it into UHV. As an example, we have deposited poly(3-dodecylthiophene) (PDDT), a polymer that shows great promise as an active component in organic electronic devices. PDDT nanostructures with lateral dimensions below 100 nm have been written on silicon oxide and gold surfaces. Using a unique UHV instrument that combines a scanning electron microsope (SEM), a scanning Auger, and in-situ four-probe measurements, we have characterized PPDT nanostructures written across prefabricated Au electrodes. I-V measurements show the nanostructures to be initially insulating (>10G@ohm@); however, the resistance unexpectedly drops several orders of magnitude (to as low as 33 k@ohm@) upon prolonged exposure to the SEM electron beam. When the beam is turned off, the resistance gradually increases (~1 G@ohm@/day). We have also found that a high resistance state can be restored by exposure to H@sub 2@, suggesting that the polymer film is not damaged by the electron beam, but rather that charged H vacancies are generated in the PPDT film by the high-energy electrons, and that the vacancies can be reversibly filled by H@sub 2@ exposure. @FootnoteText@ @footnote 1@ P. E. Sheehan, et al., Appl. Phys. Lett. 85, 1589 (2004).