1. Center of Materials Technology and Photonics & Electrical Engineering Department, Technological Educational Institute (TEI) of Crete, Heraklion 71004, Crete, Greece
2. Institute of Electronic
Structure and Laser, Foundation for Research and Technology - Hellas, P.O. Box 1527, Heraklion 71110, Crete, Greece
3. Department of Physics, University of Crete, Heraklion, 71003, Crete, Greece
4. Department of Materials
Science and Technology, University of Crete, Heraklion, 71003, Crete, Greece
5. CNR - Istituto di Struttura della Materia, Area di Ricerca di Tor Vergata, Via del
fosso del cavaliere, 100, 00133, Rome, Italy