Donchev V.1,2, Moskalenko E.S.1,3, Karlsson K.F.1, Holtz P.O.1, Monemar B.1, Schoenfeld W.V.4, Garcia J.M.5, Petroff P.M.4
1Department of Physics and Measurement Technology, Linkoping University, Linkoping, Sweden
2Faculty of Physics, Sofia University, Sofia, Bulgaria
3A.F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg, Russia
4Materials Department, University of California, Santa Barbara, California USA
5Instituto de Microelectronica de Madrid, CNM-CSIC Isaak Newton 8, PTM, Tres Cantos, Madrid, Spain