Abstarct: In this thesis the physical properties of CuS nanostructures, CuS-ZnS (CZS) binary systems and Cu2SnS3 (CTS) ternary alloy semiconductor thin films grown by spray pyrolysis method on glass and FTO substrates; also the CTS/FTO thin film diodes are studied. In this study various techniques including: Field Emission Scanning Electron Microscope (FESEM), Energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), UV-Vis-NIR spectrophotometer, Photoluminescence (PL), Hall effect, and finally the current–voltage (I-V) meter have been used. In CuS samples which were grown at different S/Cu molar ratios (0.33 and 0.43) in the temperature rang of 260-310 oC we found while the as-grown laxyers have a nanostructure feature with a polycrystalline covellite structure and preferential (102) orientation, as the substrate temperature is increased the band gap and the hole carrier density of the laxyers are decreased. Experimental data related to the influence of Zn/Cu molar ratio on physical properties of CuS-ZnS systems we found that with increasing this ratio not only the preferred (102) orientation, corresponding to CuS phase, is gradually changed to (111), the dominant crystallite direction of β-ZnS cubic phase; but also the direct band gap and the carrier density (p-type) are reduced. In Cu2SnS3 samples we found, for the first time, these laxyers are crystallized in triclinic phase; and with increasing the Sn/Cu molar ratio (between 0 to 1) the preferred (102) orientation is changed to triclinic phase. Also this variation is together with the reduction of about 1 eV in the band gap of the material. Finally we tried to fabricate a number of p/n junction diodes using CTS/FTO thin films and investigate their I-V characteristics at room temperature and in dark. The data analysis showed that in these devices the recombination currents have the dominant role in their electrical characteristic.