Study of the chalcopyrite Cu(In,Al)Se2 crystalline growth by selenization of different evaporated precursors ratios

Chalcopyrite CuInSe2 (CIS) and Cu(In,Al)Se2 (CIAS) thin films were prepared by a two-stage process onto soda-lime glass substrates. Different Cu/In and Al/(Al+In) thickness ratios have been evaporated in a vacuum chamber to be subsequently heated with elemental selenium in a quasi closed graphite box. Selenization temperatures have been varied from 150 °C to 530 °C to study the evolution of chalcopyrite growth from the metallic precursors. The results of spectrophotometry measurements, X-ray diffraction, energy dispersive analysis of X-ray and scanning electron microscopy have been interpreted for the samples with different precursors ratios and selenization temperatures, concluding that the proportion among the copper and indium precursors determines the way toward CIAS formation and crystallisation.

► Chalcopyrite CIS and CIAS thin films were prepared by a two-stage process.
► Different precursors Cu/In and Al/(Al+In) thickness ratios have been evaporated.
► Optical, morphological and structural properties have been studied.
► The proportion Cu/In determines the way toward CIAS formation and crystallisation.