Environmental harmless kesterite-related materials such as Cu2ZnSnSe4 (CZTSe), Cu2ZnSnS4 (CZTS) and Cu2ZnSn(S,Se)4 (CZTSSe) have attracted significant research interest due to their similar properties to Cu(In,Ga)Se2 (CIGS). Earth-abundant and non-toxic zinc and tin metals are the constituents in these materials. Controlled substitution of S with Se allows band gap tuning from approximately 1.5 to 1.0 eV, practically covering the optimal range for photovoltaic absorber similarly to indium-based chalcopyrites. Nowadays, the efficiency of the kesterite-based solar cell devices has reached over 10%, but their efficiencies have not yet reached the efficiency of CIGS (~20%).One key challenge of deposition processes is preparing single phase films, which is caused by the complex and incompletely understood nature of the multinary Cu-Zn-Sn-Se-S phase diagram. A second challenge of the CZTSe preparation is the process optimization involving the volatility upon heating of Sn materials, which makes composition control a challenge during film fabrication. Despite these challenges, successful film deposition and device fabrication has been demonstrates for the CZTS, CZTSe and CZTSSe absorbers and for vacuum and non-vacuum deposition approaches. The advantages of vacuum deposition methods are the high uniformity, delivery of precisely timed elemental fluxes. However, volatile elements and consequent reevaportaion from deposited films under vacuum conditions cause significant challenge. Non-vacuum deposition methods are particularly attractive for large-scale manufacturing due to their compatibility with high-throughput deposition techniques. However, incorporation of carbon, oxygen, and other impurities from the precursors or starting solution and the need for multistep processing are limitations.In this thesis, CZTSe thin films were fabricated by vacuum based sputtering and annealing. At first, precursors (Cu, Sn and ZnO) were deposited using sputtering at room temperatur...