AVS 49th International Symposium
    Nanometer Structures Friday Sessions
       Session NS-FrM

Paper NS-FrM10
Spectroscopic Scanning Tunneling Microscopy Using Semiconductor Tips with Engineered Electronic Structure

Friday, November 8, 2002, 11:20 am, Room C-207

Session: Novel Surface Nanoprobes
Presenter: P.W. Sutter, Colorado School of Mines
Authors: P.W. Sutter, Colorado School of Mines
J.S. Palmer, Colorado School of Mines
P. Zahl, Colorado School of Mines
E.A. Sutter, Colorado School of Mines
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III-V semiconductors and heterostructures are proposed as a new class of materials for use as probe tips for scanning tunneling microscopy (STM). Compared to the metal tips used conventionally, semiconductors with carefully tuned electronic properties have the potential to significantly increase energy resolution and contrast in spectroscopic STM, particularly in emerging applications such as single molecule vibrational microscopy and spectroscopy.@footnote 1@ We are exploring InAs as a candidate probe material for spectroscopic STM with ultrahigh energy resolution. Using cleaved InAs probes, we demonstrate atomic-resolution STM imaging on highly oriented pyrolithic graphite (HOPG) and on clean semiconductor surfaces, such as Si(111) 7x7. Tunneling spectroscopy with InAs probes on these materials shows clear signatures of the band structure of the semiconductor tips in local conductance spectra. Routes are studied to adjust the Fermi-level in semiconductor tip materials, thus creating a tunneling distribution that is tunable and significantly narrower than that obtainable with a conventional metal tip. @FootnoteText@ @footnote 1@ B.C. Stipe, M.A. Rezaei, and W. Ho, Science 280, 1732 (1998).