Synthesis route for transparent CuI thin films with tunable resistivities between 10–3 and 102 Ω‧cm: Chemical solution deposition of CuS2, annealing, and gas–solid iodination

Abstract

A versatile three-step sequential reaction route is presented to synthesize transparent copper iodide thin films with resistivities that can be selected in the 10–3 to 102 Ω‧cm range. The reaction process consists of (1) the chemical solution deposition of copper(I) disulfide films, (2) the synthesized copper(I) disulfide annealing at different temperatures ranging from 30 °C to 150 °C depending on the desired copper iodide resistivity, and (3) the iodination of the resulting copper(I,II) sulfides films by a gas–solid reaction with iodine vapor. The novelty of the procedure is the incorporation of versatile techniques and the consideration of the temperature-dependent formation of different types of copper sulfides, which produce copper iodide films with different electrical properties after iodination. All the films resulted quite transparent, homogeneous, and showed good adhesion to the glass substrates.