AVS 53rd International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP20
Selective Modification of Silicon-based Substrates: Reactions of Nitro-, Nitroso-, and Azido-aryls on Clean and H-terminated Si(100) and on a Surface of Silicon-filled Nanopits

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Surface Science Poster Session
Presenter: T.R. Leftwich, University of Delaware
Authors: T.R. Leftwich, University of Delaware
S.P. Sullivan, University of Delaware
T. Beebe, University of Delaware
A.V. Teplyakov, University of Delaware
Correspondent: Click to Email
The modification of silicon-based substrates has been investigated with the purpose of selective delivery of organic functional groups over a wide range of conditions. Nitro-, nitroso-, and azido-derivatives of aromatic hydrocarbons have been investigated on clean Si(100)-2x1 surface under ultra-high vacuum conditions and on H-terminated Si(100) surface under ambient conditions. These reactions were compared to analogous processes on patterned silicon-filled nanopits of 50-100 nm diameters created on a surface of highly oriented pyrolytic graphite (HOPG). The pits were created from defects formed by controlled Cs or Ga ion bombardment that were then oxidized at 923 K. These reactions were investigated using a combination of temperature-programmed desorption (TPD), infrared spectroscopy, Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT). While 1,3-dipolar cycloaddition dominates the attachment chemistry on a clean Si(100)-2x1 surface, reactions of H-terminated silicon with nitro-or nitroso-compounds proceed through condensation reactions, releasing a water molecule. For reactions of azido-compounds with a clean Si(100)-2x1 surface, a novel intermediate is suggested computationally and identified spectroscopically. This intermediate can be described as a nitrogen molecule stabilized on a silicon surface dimer by a neighboring aryl group. Selected surface intermediates and reaction pathways have been investigated computationally. These findings were applied to modify silicon nanostructures formed on a surface of HOPG.