[1] Slovak Univ Technol Bratislava, Dept Microelect, Bratislava 81219, Slovakia
[2] Univ Wurzburg, Inst Phys, D-97074 Wurzburg, Germany
[3] Tech Univ Bergakad Freiberg, D-09596 Freiberg, Germany
[4] Univ London Imperial Coll Sci Technol & Med, Dept Mat, London SW7 2BP, England
[5] Inst Schichten & Grenzflachen, D-52425 Julich, Germany
[6] Wroclaw Univ Technol, Fac Microsyst Elect & Photon, PL-50237 Wroclaw, Poland
[7] Ctr Int Laser, Bratislava 81219, Slovakia