1. Department of Materials Science and Nanoengineering, Rice University, Houston, Texas 77005, United States
2. School of Sciences, Department of Physics and Meteorology, São Paulo State University (Unesp), Bauru, São Paulo 17033-360, Brazil
3. DEVCOM Army Research Laboratory, Adelphi, Maryland 20783, United States
4. Chemistry Division, Naval Research Laboratory, Washington, D.C. 20375, United States
5. Shared Equipment Authority, Rice University, Houston, Texas 77005, United States