Low cost CuInSe2 thin films production by stacked elemental layers process for large area fabrication of solar cell application

Low cost deposition of large area CuInSe2 (CIS) thin films have been grown on Mo-coated glass substrate by simple and economic stacked elemental layer deposition technique in vacuum. The grown parameters such as concentration of Cu, In and Se elements have been optimized to achieve uniform thin film in vacuum chamber. The as-grown Cu/In/Se stacked layers have been annealed at 200 °C and 350 °C for 1 h in air ambient. The as-grown and annealed films have been further subjected to characterization by X-ray diffraction (XRD), optical absorption, atomic force microscopy (AFM) and I–V measurement techniques. XRD patterns revealed that as-grown Cu/In/Se stacked layers represent amorphous nature while annealed CIS film reproduces nano-polycrystalline nature with chalcopyrite structure. The optical band gap of annealed films increases with respect to air annealing which confirms the reduction of crystallite size. Surface morphology of as-grown Cu/In/Se stacked layers and annealed CIS thin films have been confirmed by AFM images. The electrical measurements show enhancement of conductivity which is useful for solar cell application.

► CuInSe2 (CIS) thin film has deposited by stacked elemental layer technique (SEL).
► CuInSe2 phase have been obtained after annealing at temperature 350 °C.
► The structural, morphology and electrical properties have been obtained.
► The red shift in energy band gap of CIS thin films are found due to annealing.