1. Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssinière, BP32229, 44322 Nantes, France, School of Electrical, Electronic and Computer Engineering, University of Newcastle, Newcastle Upon Tyne, NE1 7RU, United Kingdom, and Atomic Energy Commission, Department of Chemistry, P.O. Box 6091, Damascus, Syria