1. Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Electrum 229, SE-16440 Kista, Sweden
2. Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
3. Department of Physics Education, Korea National University of Education, Cheongju 28173, South Korea
4. NanOsc AB, Kista 164 40, Sweden
5. International Iberian Nanotechnology Laboratory (INL), Av. Mestre José Veiga s/n, 4715-330 Braga, Portugal