1. Department of Chemistry and Laboratory for Emerging Materials and Technology, Clemson University, Clemson, South Carolina 29634, United States
2. National Institute for Research and Development in Microtechnologies, IMT-Bucharest, Bucharest 077190, Romania
3. Nanotechnology Measurements Division, Agilent Technologies, Inc., Chandler, Arizona 85226, United States
4. Department of Oxide Materials and Nanomaterials, Faculty of Applied Chemistry and Material Science, University Politehnica of Bucharest, Bucharest, Romania