1. Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
2. Applied Physics Graduate Program, Northwestern University, Evanston, Illinois 60208, United States
3. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
4. Department of Material Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
5. Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, Greece
6. Department of Physics, Missouri University of Science and Technology, Rolla, Missouri 65409-0640, United States
7. Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208, United States
8. Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208, United States