Thickness dependent studies of chemically grown transparent conducting Cu:ZnS thin films for optoelectronic applications

• Published in: Optical materials 2021-10, Vol.120, p.111469, Article 111469
• Main Authors: Khatri, Rajeshkumar P., Patel, Amitkumar J.
• Format: Article
• Language: English
• Subjects: Chemical bath deposition (CBD); Cu-doped ZnS; Transparent conducting sulphide (TCS)
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2021.111469

Copper-doped Zinc Sulphide (Cu:ZnS) thin films were grown on silica slides with a different number of coats varying from 1 to 4 using a low-cost chemical bath deposition technique. In order to investigate its applicability as an alternative to transparent conducting oxides (TCOs), structural, optical, and electrical characterizations were performed with varied film thickness. The thickness of the films was varied from 205 nm to 713 nm with different number coats. X-ray diffraction study revealed cubic phase with sphalerite structure for the films. The effect of thickness on structural parameters is reported. UV/VIS/NIR spectroscopy demonstrated that transmittance varies from 98% to 41% in the visible region with film thickness. The increase in film thickness led to the narrowing of band gap values. The electrical conductivity between 1.82 and 10.3 Ω-1⋅cm−1 and charge carrier density in the range of 1020 to 1022 cm−3 were observed in the obtained films. The maximum mobility was 0.185 cm2/V.s. The reported results show that the Cu:ZnS thin film has enough potential to use as transparent conducting sulphide (TCS) film for optoelectronic applications. [Display omitted] •Optically transparent and electrically conducting Cu:ZnS thin films are deposited by the chemical route.•The film's thickness significantly influences the structural, morphological, optical, and electrical properties.•The broadening of band gap is observed with decreasing the films' thickness.•The minimum resistivity of 9.68 × 10−2 (Ω cm), and the highest mobility of 1.85 × 10−1 (cm2/V·s) were reported.•The obtained Cu:ZnS films have a potential to use in the optoelectronics field.