1. Department of Physics, North Dakota State University, Fargo, North Dakota 58108, United States
2. Materials & Nanotechnology Program, North Dakota State University, Fargo, North Dakota 58108, United States
3. Department of Chemistry & Biochemistry, North Dakota State University, Fargo, North Dakota 58108, United States
4. Department of Coatings & Polymeric Materials, North Dakota State University, Fargo, North Dakota 58108, United States