1. Integrated Nanotechnology Research Center (INRC) and Small & Strong Materials Group (SSMG), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen, 40002 Thailand, Department of Chemistry, Faculty of Science, Ubon Ratchathani University, Varinchamrap, Ubon Ratchathani 34190, Thailand, and Department of Materials Science and Engineering, The University of Arizona, Tucson, Arizona 85721