Low-Temperature Direct Conversion of Cu-In Films to CuInSe2 via Selenization Reaction in Supercritical Fluid

In this study, we achieve the direct conversion of metallic Cu-In films to compound semiconductor CuInSe2 films, at quite low temperature around 300 degrees C using less hazardous metalorganic selenium source in supercritical fluid (SCF). We investigated the effects of temperature and fluid (ethanol) density, and found that supercritical ethanol plays a crucial role in this low-temperature selenization reaction. Such SCF-assisted direct conversion reactions can facilitate large-scale, low-temperature, and rapid synthesis of CuInSe2 films, which can potentially lead to the low-cost production of solar cells.