1. Photon Science Institute; University of Manchester; Manchester M13 9PL UK
2. Department of Physics and I3N; University of Aveiro, Campus Santiago; Aveiro 3810-193 Portugal
3. Department of Engineering Sciences and Mathematics; Luleå University of Technology; SE-97187 Luleå Sweden
4. Materials Research Center of NAS of Belarus; Minsk 220072 Belarus
5. SunEdison Semiconductor Ltd.; viale Gherzi 31 28100 Novara Italy
6. SunEdison Inc.; 7832 N. Leadbetter Rd. Portland Oregon 97203 USA
7. Department of Physics; SMN, University of Oslo; Oslo N-0316 Norway