Effect of Sn concentration on optical and structural properties of Pb1-xSnxS nanopowderRahim Lotfi Orimi, Hasan Khandan Fadafan and Alameh AsadpourEur. Phys. J. Appl. Phys., 67 2 (2014) 20404DOI: https://doi.org/10.1051/epjap/2014140159