1. Laboratory of Inorganic Chemistry,
Department of Chemistry, University of Helsinki P.O. Box 55, FI-00014
Helsinki, Finland
2. Institute
for Solid State Electronics,
Vienna University of Technology, A-1040 Vienna, Austria
3. Department of Applied Physics,
Technische Universiteit Eindhoven, P.O. Box 5135600 MB Eindhoven,
The Netherlands
4. Air Liquide Research & Development, DRTC, 200 GBC Drive, Newark, Delaware 19702, United States