AVS 52nd International Symposium
    Biomaterial Interfaces Friday Sessions
       Session BI+SS-FrM

Paper BI+SS-FrM1
Charge Injection Barriers and Gap States at the L-Cysteine/Au Interface

Friday, November 4, 2005, 8:20 am, Room 311

Session: Biomaterials Surface Characterization
Presenter: M.M. Beerbom, University of South Florida
Authors: M.M. Beerbom, University of South Florida
R. Gargagliano, University of South Florida
R. Schlaf, University of South Florida
Correspondent: Click to Email
Protein/inorganic materials interfaces are interesting for many bio-engineering applications such as bio-sensors or molecular electronic devices. L-cysteine is particularly interesting since it can form self-assembled monolayers on gold due to its thiol-group. In our experiments we investigated the L-cysteine/Au interface using x-ray and ultraviolet photoelectron spectroscopy (XPS, UPS) in combination with a multi-step deposition procedure. PE-spectra obtained after each deposition step yielded a data set allowing the determination of charge injection barriers at the interface, as well as the characterization of the chemical interaction. The L-cysteine deposition was carried out in a glove box directly attached to the PES system enabling contamination-free measurements. Our results indicate the formation of an interface state within the HOMO-LUMO gap due to the thiol-Au interaction.@footnote 1@ This is supported by control experiments on L-cysteine/graphite interfaces, which did not show the formation of this gap state. @FootnoteText@ @footnote 1@M.M. Beerbom, R. Gargagliano and R. Schlaf: "Determination of the Electronic Structure of Self-Assembled L-cysteine/Au Interfaces Using Photoemission Spectroscopy", Langmuir Articles ASAP), (2005).