1. Department of Mechanical Engineering, University of Maine, Orono, Maine 04469, United States
2. Frontier Institute for Research in Sensor Technologies, University of Maine, Orono, Maine 04469, United States
3. Columbia Nano Initiative, Columbia University, New York, New York 10027, United States
4. Ellipsometry Applications Engineering Group, J.A. Woollam Company, Lincoln, Nebraska 68508, United States
5. Department of Chemistry, University of Maine, Orono, Maine 04469, United States