1. Microelectronic Department, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava, Slovakia
2. Physikalisches Institut, Universität Würzburg, 97074 Würzburg, Germany
3. Department of Materials, Imperial College, Prince Consort Road, London SW7 2BP, UK
4. Faculty of Microsystem Electronics and Photonics, Wrocław University of Technology, Z. Janiszewskiego 11/17, 50‐372 Wrocław, Poland