AVS 57th International Symposium & Exhibition
    Applied Surface Science Wednesday Sessions
       Session AS-WeM

Paper AS-WeM2
Synthesis and Characterization of Gold Nanocluster-Cavity Pairs in SrTiO3

Wednesday, October 20, 2010, 8:20 am, Room Cochiti

Session: New Ion Beam Technologies for Imaging, Sample Preparation and Analysis
Presenter: T. Thevuthasan, Pacific Northwest National Laboratory
Authors: S.V. Shutthanandan, Pacific Northwest National Laboratory
C.M. Wang, Pacific Northwest National Laboratory
B. Arey, Pacific Northwest National Laboratory
W. Jiang, Pacific Northwest National Laboratory
Y. Zhang, Pacific Northwest National Laboratory
T. Thevuthasan, Pacific Northwest National Laboratory
G. Duscher, Oak Ridge National Laboratory
Correspondent: Click to Email
Dispersion of gold nanoclusters in single crystal TiO2, MgO, and SrTiO3 have been found to influence the optical properties of the materials. One way to make these clusters in these oxide media is through Au ion implantation followed by annealing at high temperatures for extended period of time. The Au clusters generated by this ion beam synthesis method often associated with vacancies as a cluster-vacancy pair in the matrix. These nanometer scale vacancy clusters are generally called quantum antidotes and they are believed to be spatially located at the interface between the Au clusters and the matrix. To verify this proposition, Au nanoclusters dispersed in SrTiO3 single crystals were prepared using ion implantation at 975 K and subsequent annealing at 1275 K for 10 hours. We have used a suite of imaging capabilities including newly developed Helium ion microscopy (HIM) and scanning transmission electron microscopy (STEM) with high-angle-annular-dark-field (HAADF) imaging to understand the structural properties and spatial distribution of the Au and vacancy clusters. The results indicate that gold nanocluster-cavity pairs were formed uniformly throughout the implanted region. Size of the Nanocluster-cavity pairs ranges from 5 to 30 nanometers. In cluster free regions where the Au concentration is low, the HADDF results clearly indicate the substitution of Au for cations. The Au clusters and the cavity show spatial association, indicating a strong interaction during their respective clustering process.