1. Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, New Jersey 08854, USA
2. Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA
3. Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
4. Department of Physics, Auburn University, Auburn, Alabama 36849, USA
5. Evans Analytical Group, East Windsor, New Jersey 08520, USA