1. Department of Materials Science and Engineering, University of Texas at Dallas 1 , Richardson, Texas 75080
2. Micron Technology Inc. 2 , Boise, Idaho 83707
3. Materials Science and Engineering Program and Department of Chemistry and Biochemistry, University of California, San Diego 3 , La Jolla, California 92093
4. Department of Chemistry, Wayne State University 4 , 5101 Cass Avenue, Detroit, Michigan 48202