[1] Tech Univ Clausthal, Inst Energieforsch & Phys Technol, D-38678 Clausthal Zellerfeld, Germany
[2] Fak Nat Wissensch & Tech, Hsch Angew Wissensch & Kunst, D-37085 Gottingen, Germany
[3] Fraunhofer Inst Schicht & Oberflachentech IST, APP, D-37085 Gottingen, Germany
[4] Tech Univ Clausthal, Clausthaler Zentrum Mat Tech, D-38678 Clausthal Zellerfeld, Germany