Enhanced transmittance and mobility of p-type copper iodide thin films prepared at room temperature via a layer-by-layer approach

• Published in: Surface & coatings technology 2019-03, Vol.361, p.396-402
• Main Authors: Geng, Fangjuan, Yang, Lei, Dai, Bing, Guo, Shuai, Gao, Gang, Xu, Liangge, Han, Jiecai, Bolshakov, Andrey, Zhu, Jiaqi
• Format: Article
• Language: English
• Subjects: Copper; Iodination; Layer by layer procedure; Morphology; Optoelectronics; P-type transparent conductor; Room temperature; Room-temperature synthesis; Thickness; Thin films; Transmittance; X-ray diffraction; Zincblende
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2019.01.057

High-quality, transparent, conducting, p-type γ-CuI thin films are prepared via an innovative layer-by-layer procedure based on the traditional simple iodination of Cu films (referred to as the LBL-I method) at room temperature (RT). The structure, morphology, and optoelectronic properties of the γ-CuI are investigated as functions of the per layer thickness. The final thicknesses of LBL-I γ-CuI films are consistent with that in the film prepared by the traditional one-step method (TOS). X-ray diffraction analysis reveals that all the films are polycrystalline with the most dominant (111) direction of the zinc blende structure, indicating the facile and successful fabrication of γ-CuI. Compared with the TOS film, the LBL-I films display enhanced transmittance and mobility. The higher transmittance of >80% in the visible region of LBL-I films was attained due to the smaller root-mean-square roughness values of 23–28 nm. The 50 nm/l LBL-I CuI films have mobility values of 6.9–9.4 cm2 V−1 s−1, and lower resistivity of 0.039–0.05 Ω cm, which assist studies on applications of γ-CuI thin films in transparent electronics. •High-quality electrooptical properties p-type γ-CuI thin films are prepared.•Innovative layer-by-layer approach based on Cu films iodination (LBL-I) is used.•LBL-I films show better transmittance and mobility than films prepared in one step.