Study of the structural, electrical and optical properties of Ge-Pb-Te nanocrystals Iman A. Mahdy, Manal A. Mahdy and S. M. El Sheikh Eur. Phys. J. D, 70 12 (2016) 264 Published online: 15 December 2016 DOI: 10.1140/epjd/e2016-70307-2