[1] EME, University of Barcelona, Assocaited Unit to CNIM-CSIC, c/Martí i Franquès 1, ES-08028 Barcelona, Spain
[2] CNM-CSIC, Campus UAB, ES-08193 Bellaterra, Spain
[3] Forschungszentrum Rossendorf, PO Box 510119, DE-01314 Dresden, Germany
[4] KTH, Electrum 229, SE-16440 Kista, Sweden
[5] IMC Indust. Microelectronics Center, Electrum 233, PO Box 1084, SE-16440 Kista, Sweden
[6] EMAT-RUCA, University of Antwerpen, Groenenborgerlaan 171, BE-2020 Antwerpen, Belgium