1. Nanoscale Engineering Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden
2. Institut P', Département Physique et Mécanique des Matériaux, Université de Poitiers-CNRS-ENSMA, SP2MI, Téléport 2, Bd M. et P. Curie, F-86962 Chasseneuil-Futuroscope, France
3. Plasma and Coatings Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden