AVS 47th International Symposium
    Processing at the Nanoscale/NANO 6 Friday Sessions
       Session NS+NANO6+MC-FrM

Paper NS+NANO6+MC-FrM5
Tunneling Spectroscopy of Passivated Gold Nanocrystals

Friday, October 6, 2000, 9:40 am, Room 302

Session: Nanoscale Spectroscopy
Presenter: R.B. Wyrwas, Georgia Institute of Technology
Authors: R.B. Wyrwas, Georgia Institute of Technology
A.Y. Ogbazghi, Georgia Institute of Technology
T.P. Bigioni, Georgia Institute of Technology
L.E. Harrell, Georgia Institute of Technology
T.G. Schaaff, Oak Ridge National Laboratory
R.L. Whetten, Georgia Institute of Technology
P.N. First, Georgia Institute of Technology
Correspondent: Click to Email
Scanning tunneling spectroscopy (STS) and microscopy (STM) have been used to study the electronic structure of small (< 2 nm diameter) alkanethiol-passivated gold nanocrystals. The nanocrystals were prepared via chemical methods, and their mass distribution was characterized by time-of-flight mass spectrometry. STM/STS measurements were done at room temperature, 77 K, and 8 K, with isolated nanocrystals immobilized on Au(111) surfaces by a xylenedithiol self-assembled monolayer (SAM). A histogram of nanocrystal heights measured by STM shows several peaks. These correlate well with distinct peaks in the mass spectrum. STS dI/dV spectra vary with nanocrystal size, and show prominent features due to their quantized density-of-states. Spectra acquired repeatedly over a single nanocrystal evolve in time slowly, possibly due to configurational changes of the nanocrystal or its passivation layer.