1. Graduate School of Engineering, Tokai University, Hiratsuka 259-1292, Japan
2. Electrical Engineering Section, Universiti Kuala Lumpur British Malaysian Institute, 53100 Gombak, Selangor, Malaysia
3. Laboratoire GREMAN CNRS-UMR 7347, IUT de BLOIS, 15, rue de la Chocolaterie, C. S. 32903, 41029 Blois Cedex, France
4. Institut Català de Nanociència i Nanotecnologia (ICN2), ICN2 Building, UAB Campus, 08193 Bellaterra, Spain