Semiconductor nanocrystals have electronic properties between those of molecular entities and macrocrystalline solids. It is well known that nanocrystalline semiconductor exhibits quantum confinement effect and posses novel optical, electrical and chemical properties that are significantly different from those of their bulk counterparts [1]. Research on other semiconductors, and especially wide band gap (WBG) semiconductors have allowed realizing a great variety of power devices: Schottky diodes, bipolar devices, MOSFET, JFET [2]. Among these nanomaterials, SnS and PbS are particularly attractive and received impressive attention because of their nonlinear optical behavior and unusual fluorescence or photoluminescence properties [3]. Herein, we report a successfully and easily synthesized spherical SnS and PbS nanoparticles as WBG semiconductors in narrow particle size by thermal decomposition method using SnCl2 and Pb(NO3)2 as readily available metal precursor at mild condition. Nanoparticles were characterized by several techniques, including TEM, XRD, FT-IR, EDAX and PL analysis. Actually, we confirmed that the gap between valence band and conduction band has reverse dependence on nanoparticle size. Further works are in progress to obtain a class of WBG semiconductors and in combination with photosensitive metal sulfide nanoparticles that could be use in solar cells.
