CHARACTERIZATION OF Cu2ZnSnS4 THIN FILMS PREPARED BY VAPOR PHASE SULFURIZATION

Cu2ZnSnS4 (CZTS) thin films could be formed by vapor phase sulfurization of e-beam-evaporated precursors on a soda-lime glass substrate. This film is an interesting material for absorber layer in a solar cell because all the constituents are readily available in the earth's crust. In this study, using a new type of precursor containing ZnS, authors could achieve the strong adhesion of CZTS films to a glass substrate. From the result of SEM observation, it was confirmed that the surface morphology of CZTS films is much improved by using this new type of precursor. The XRD pattern revealed that CZTS thin films have kesterite structures. From the measurement of transmittance and reflectance, the optical band-gap energy was estimated as 1.40-1.45 eV, which is close to the optimum value for a solar-cell absorber. The highest open-circuit voltage of cells based on CZTS films is 735 mV, which is a higher value than that reported in numerous other studies on CZTS. 12 refs.