Fabrication of Cu(In,Ga)Se₂ thin films by a combination of mechanochemical and screen‐printing/sintering processes

Abstract

Abstract We prepared fine Cu(In,Ga)Se 2 (CIGS) powder suitable for screen printing using a mechanochemical process. Particulate precursors were deposited in a thin layer by a screen‐printing technique, the remaining organic solvent was removed from the screen‐printed CIGS film and finally the porous precursor layer was sintered into a dense polycrystalline film by atmospheric‐pressure firing. The crystal structure of the film was analyzed by X‐ray diffraction and the microstructure was observed in a SEM. The thickness of the film was 5–10 μm with a grain size of about 2 μm. The films were also observed in a TEM. The grain size of the as‐prepared powder was less than 1 μm; however, it enlarged to 2–3 μm after firing at 575 °C under a Se ambient. Preliminary CIGS solar cells with our standard Al grid/B‐doped ZnO/i‐ZnO/ CdS/CIGS/Mo/soda‐lime glass structure were fabricated. An efficiency of 2.7%, a V oc of 0.325 V, a J sc of 28.3 mA/cm 2 and a FF of 0.295 was obtained. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)