1. Department of Mechanical and Electrical Engineering University of Southern Denmark Sønderborg DK-6400 Denmark
2. Department of Physics Faculty of Science Ferdowsi University of Mashhad Mashhad 9177948974 Iran
3. NanoSYD Mads Clausen Institute University of Southern Denmark Sønderborg DK-6400 Denmark
4. Department of Physics and Astronomy Uppsala University Box-516 Uppsala 75120 Sweden