1. Inorganic Chemistry Department; National Research Centre; 33 El-Behouth St., Dokki Giza 12622 Egypt
2. Nanomaterials and Nanotechnology Department; Central Metallurgical R & D Institute; Cairo 11421 Egypt
3. Electron Microscope & Thin films Department, Physics Division; National Research Centre; 33 El-Behouth St., Dokki Giza 12622 Egypt