AVS 55th International Symposium & Exhibition
    Nanometer-scale Science and Technology Tuesday Sessions
       Session NS-TuP

Paper NS-TuP21
Nanofabrication by Near-Field Photochemical Modification of Phosophonic Acid Monolayers on Titanium Dioxide

Tuesday, October 21, 2008, 6:30 pm, Room Hall D

Session: Poster Session
Presenter: G. Tizazu, University of Sheffield, UK
Authors: G. Tizazu, University of Sheffield, UK
G. Leggett, University of Sheffield, UK
D.G. Lidzey, University of Sheffield, UK
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Phosphonic acid self assembled monolayers were formed on titanium oxide surfaces. Exposure of the samples to a UV light of wave length 244nm through a mask resulted in photo degradation of the monolayers in exposed areas leaving undegraded molecules in unexposed areas. Titanium oxide microstructures were produced by immersing the photo patterned samples in to a KOH solution. The phosphonic acid monolayers exhibited a surprising “switchable” character, performing as positive tone resists at low UV exposures but behaving as negative tone resists at high exposures. Backfilling the photo-degraded monolayers with a second phosphonic acid molecule with a different end group (for example an amine terminated adsorbate) yielded patterns consisting of regions with different chemical compositions. Aldehyde and amine modified fluorescent nanoparticles were attached to the chemically patterned surfaces, demonstrating their potential for fabricating complex functional architectures. Nanometre scale structures were produced by utilising a scanning near-field optical microscope (SNOM as the light source.