Cu2ZnSnS4 (CZTS) is a novel quaternary compound which contains Cu, Zn, Sn and S elements. It is a p-type semiconductor which has been taken attention in the last years as an absorber layer. Since it consists of abundant, low cost and non-toxic elements, it is one of the most promising candidate as an absorber layer for thin film photovoltaic (PV) application. Having high absorption coefficient, low bandgap value which is theoretically in desired range make this material attractive for solar cell application. In this thesis, CZTS absorber layers were grown using two stages which are the magnetron sputtering of metallic precursors, followed by a heat treatment under sulfur vapor atmosphere. Two types of CZTS were grown such as SLG/Mo/Cu (55nm)/Sn/Zn/Cu (120nm) and SLG/Mo/Cu (120nm)/Sn/Zn/Cu (55nm). For the same stacking order, the effect of Cu thickness sequentially grown with Sn layer on the film quality were investigated. The optical properties, microstructure, surface and bulk composition of CZTS films were investigated in detail. This study revealed a correlation between the CZTS stacking order having different thickness of Cu layer and the improvement of film quality, which was also confirmed by the photo-conversion efficiency of the fabricated devices. In this work, the other investigated layer is CdS which is an n-type semiconductor with bandgap energy of 2.4 eV. Since CdS has well lattice match with the heterojunction between CdS and CZTS, it is one of the most preferred material as a buffer layer for solar cells. In this work CdS buffer layers were deposited by chemical bath deposition technique. The optimization of CdS layers were occurred and optical, structural, bulk and surface compositions were investigated in detail. Finally, SLG/Mo/CZTS/CdS/i-ZnO/AZO devices were fabricated. The effect of structure properties of CZTS films and the thickness of CdS buffer layer on efficiency of fabricated solar cells were investigated.