1. Department of Solid State Engineering, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic
2. Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic
3. Materials Centre, Faculty of Science, J. E. Purkyně University, Pasteurova 15, 40096 Ústí nad Labem, Czech Republic