AVS 53rd International Symposium
    Nanometer-scale Science and Technology Thursday Sessions
       Session NS-ThP

Paper NS-ThP28
Fabrication and Characterization of Reproducible SERS Substrates for Trace Chemical Detection

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Nanoscale Science and Technology Poster Session
Presenter: G. Ertas, Bilkent University, Turkey
Authors: Sevnur Komurlu, Bilkent University, Turkey
S. Yilmaz, Bilkent University, Turkey
G. Ertas, Bilkent University, Turkey
S. Suzer, Bilkent University, Turkey
Correspondent: Click to Email
Gold nanoparticles are of fundamental interest and technological importance because of their applications in surface-enhanced Raman scattering (SERS). Gold nanoparticles having size range from ca. 5 to 100 nm have been prepared in three steps. Firstly, small spherical particles (seeds) of diameters ca. 2 nm were prepared by varying the ratio of gold ion concentration to citrate/NaBH4 concentration. Secondly, larger particles were formed by a seed-mediated growth where small particles produced by the above technique were exploited as seeds and fresh Au(III) ions were reduced onto the surface on the seed particles by citrate ions. This seeding method repeated one more time and these nanoparticles were deposited onto amine-terminated substrates, which were obtained by modifying glass surfaces with 3-aminopropyltrimethoxysilane (APS). Such substrates possess amine surface functionality and uniform morphology, which can offer abundant and easily accessible binding sites for nanoparticles. SERS substrates consisting of gold nanoparticles deposited on glass slides are used to examine SERS effect of amino acids; lysine, histidine and aspartic acid. We use XPS to verify the deposition of the Au nanoparticles on APS substrate and amino acids on gold nanoparticles by recording the Au4f and N1s signals before and after immobilization steps. In addition, by controlling the charging/discharging via external voltage stress we can induce additional spectral separation of the XPS peaks of nitrogen in two different forms (amino acid and APS) present on the same surface.