AVS 50th International Symposium
    Processing at the Nanoscale Thursday Sessions
       Session PN-ThA

Paper PN-ThA7
Templated Growth of One-dimensional Molecular Wires on Si(100) Using Multi-step Feedback Controlled Lithography

Thursday, November 6, 2003, 4:00 pm, Room 317

Session: Molecular Monolayers
Presenter: R. Basu, Northwestern University
Authors: R. Basu, Northwestern University
N.P. Guisinger, Northwestern University
M.C. Hersam, Northwestern University
Correspondent: Click to Email
This study demonstrates the fabrication of one-dimensional molecular wires on the Si(100) surface with atomically precise control over the position and length of each wire. Specifically, styrene molecules, which are known to experience self-directed growth on Si(100) surface along dimer rows, have been induced to grow from individual dangling bonds that have been created on the hydrogen-passivated Si(100)-2x1 surface through feedback controlled lithography (FCL) using a room temperature ultra-high vacuum (UHV) scanning tunneling microscope (STM). The site-specific creation of individual dangling bonds allows control over the position of the styrene wires whose growth is confined along a dimer row. FCL has also been used to create an additional pair of dangling bonds at two different positions within the same dimer row to allow for controlled chemisorption of the organic free radical, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO). The presence of the bounded TEMPO molecules physically restricts the growth of the styrene chain beyond the specified length along the dimer row and thus allows unprecedented control over the length of the molecular wires. Current-voltage spectroscopy has been performed on the styrene and TEMPO molecules. Based on the spectroscopic data, bias dependent STM conductance images of the molecular wires have been obtained.