1. Material Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
2. Department of Materials Science
and Engineering, University of California, Berkeley, California 94720, United States
3. Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
4. Department of Physics, Tamkang University, Tamsui, Taiwan 250, R. O. C.
5. Department of Chemistry, University of California, Berkeley, California 94720,
United States
6. London Centre for
Nanotechnology and
Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
7. Interdisciplinary Nanoscience
Center (iNANO) and Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark