Properties of CuInS₂ Thin Films Fabricated by SEL Method

CuInS₂ thin films were fabricated by sulphurization of S/In/Cu Stacked elemental layers (SEL) on slide glass substrates by annealing in vacuum of 10⁻³ Torr at temperature of 50 °C ∼ 350 °C. Some S/In/Cu SEL were vacuum annealed under a sulfur atmosphere. The thin films thus annealed were analyzed by measuring structural, electrical and optical properties. When CuInS₂ thin films were made under a sulfur atmosphere, lattice constant of a and grain size of the thin film were a little larger than those in only vacuum annealing. The largest lattice constant of a and grain size was 5.63 Å and 1.2 μm respectively. Also, when the thin films were made under a sulfur atmosphere, conduction types were all p-type with resistivities of around 10⁻¹ Ωcm and optical energy band gaps of the films were a little larger than those in only vacuum and the largest optical energy band gap of CuInS₂ thin film was 1.53 eV.