Preparation and characterization of sputtered CuInSe2 thin films using a single target composed of a mixture CuSe and InSe binary selenides powders

摘要

In this study, the viability of growing a CuInSe2 thin film solar absorber by sputtering using a single target composed of CuSe and InSe powders was investigated. It was found that the ability to obtain a sputtered film with a stoichiometric composition was greatly dependent on the substrate temperature and that the optimum conditions could be obtained by adjusting the sputtering radio frequency power. A single phase chalcopyrite CuInSe2 film with a nearly stoichiometric composition and strong (112), (220/204) and (312/116) reflections was successfully grown under the optimized growth condition. The CuInSe2 films exhibit an absorption coefficient of 10⁴ cm^-1 and an optical band gap of 1.0 eV. According to the Hall measurements, the sputtered CuInSe2 film showed p-type semiconductor characteristics, which is in good agreement with the non-stoichiometry (Δy≫0) and non-molecularity (Δx) model.