Optimization of the nitrogen content for room temperature rapid synthesis of CuI thin films via liquid iodination method using Cu₃N film as precursor

Abstract

In this work, we demonstrate that CuI films can be obtained by the liquid–phase iodination method with the chemical reaction time only being 1 min between Cu₃N and aqueous iodine solution at room temperature. This is a simple and eco-friendly method with high transparency and low resistivity. The Cu₃N precursors were prepared by reactive DC magnetron sputtering using different N₂ partial pressures. The effect of nitrogen content of precursor (Cu₃N) on the structural, electrical, and optical properties of CuI thin films was discussed. Electronegativity property was used to explain the growth mechanism of CuI films prepared by different nitrogen content in the precursor. By growing the CuI films with a N₂:Ar gas ratio of 5:2, the average transmittance achieved was 75% in the visible spectral range, and the lowest resistivity achieved was 3.67 × 10^–2 Ω cm. These results suggest that the liquid iodination method using Cu₃N film as precursor (N₂:Ar gas ratio of 5:2) was suitable for preparing high-quality CuI films for application in transparent electronics.