1. Department of Materials Science and Technology; University of Crete; Heraklion 71003 Greece
2. Inorganic Chemistry, Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen; Universitaetsstr. 5-7 Essen 45117 Germany
3. Tomsk State University and ISPMS RAS; 2/4 Academicheskii Avenue Tomsk 634021 Russia
4. IESL-FORTH; Vasilika Vouton; Heraklion 71110 Greece