Optical and Electrical Properties of Copper Zinc Tin Sulfide Films As Solar Cell Absorber Materials Prepared by a Compacting Process

The copper zinc tin sulfide (CZTS) thin films are prepared by a promising non vacuum compacting process based on ball milling and coating technique. The results reveal that a well-formed crystalline structure of kesterite CZTS are observed after sintering at 450°C. The optical band gap is 1.49, 1.59, 1.33, and 1.21 eV for the films with Cu/Zn/Sn atomic radio of 1.00 : 0.50 : 0.52, 1.00 : 0.44 : 0.41, 1.00 : 0.60 : 0.49, and 1.00 : 0.49 : 0.58, respectively. The compacting process can further improve the performances of CZTS film. For the CZTS thin film with Cu/Zn/Sn atomic radio of 1.00 : 0.60 : 0.49, the surface morphology of the film is significantly improved by a compacting process applied to the coating films before sintering, and the resistivity decreased from 23.67 to 1.18 Ω cm with the compacting pressure increasing from 0 to 200 MPa at room temperature, which showing a promising application of the compacting process method in fabricating CZTS film for solar cells.