Preparation of CuInSe2 thin films by paste coating

Precursor pastes were obtained by milling Cu-In alloys and Se powders. CuInSe2 thin films were successfully prepared by precursor layers, which were coated using these pastes, and were annealed in a H2 atmosphere. The pastes were tested by laser particle diameter analyzer, simultaneous thermogravimetric and differential thermal analysis instruments (TG-DTA), and X-ray diffractometry (XRD). Selenized films were characterized by XRD, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The results indicate that chalcopyrite CuInSe2 is formed at 180°C and the crystallinity of this phase is improved as the temperature rises. All the CuInSe2 thin films, which were annealed at various temperatures, exhibit the preferred orientation along the (112) plane. The compression of precursor layers before selenization step is one of the most essential factors for the preparation of perfect CuInSe2 thin films.