1. Department of Chemistry, Physics and Materials Science, Fayetteville State University, Fayetteville, North Carolina 28301, United States
2. X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
3. Chapel Hill Analytical and Nanofabrication Laboratory, University of North Carolina, Chapel Hill, North Carolina 27599, United States
4. Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States