Electrodeposition of ZnS Thin Films by Complexing Agent-Free Electrolyte Containing Sodium Thiosulfate as the Sulfur Precursor

• Published in: Journal of electronic materials Vol. 50; no. 8; pp. 4324 - 4332
• Main Authors: Madhuwanthi, H. M. L. U., Mahanama, G. D. K., De Silva, D. S. M.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2021; Springer Nature B.V
• Subjects: Atomic force microscopy; Buffer layers; Carrier density; Characterization and Evaluation of Materials; Charge density; Chemistry and Materials Science; Current carriers; Electrodeposition; Electrolytes; Electronics and Microelectronics; Fluorine; Glass substrates; Heat treatment; Instrumentation; Materials Science; Microscopy; Optical and Electronic Materials; Original Research Article; Photovoltaic cells; Sodium thiosulfate; Solar cells; Solid State Physics; Thin films; Tin oxides; Zinc sulfide; Buffer layer; sodium thiosulfate; zinc sulfide; electrodeposition; complexing agent free
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-021-08948-y

Thin films of zinc sulphide (ZnS) were prepared by a facile, economical, and scalable electrochemical method as a buffer layer for a CdS/CdTe based solar cell. Herein, a three-electrode cell in a complexing agent-free electrolyte containing 0.1 mol/L Na 2 S 2 O 3 and 0.1 mol/L ZnSO 4 was employed for the deposition of ZnS. The electrodeposition conditions (temperature: 30°C, pH: 4.2, cathodic potential: −1.10 V and deposition time: 90 min) were identified to grow an ideal thin film of ZnS on fluorine-doped tin oxide (FTO)-coated glass substrate, applying moderate stirring of 60 rpm. In material characterization of heat-treated samples (300°C, 10 min), the optical absorption measurement depicted a direct energy bandgap of 3.64 eV with low light absorbance and a blueshift from bulk ZnS. Scanning electron microscopy and atomic force microscopy studies demonstrated the uniform distribution of ZnS grains over the FTO glass substrate, and x-ray diffraction analysis revealed an amorphous structural nature of ZnS. The charge carrier density and flat-band potential of the ZnS material were determined as 1.19 × 10 −19 cm −3 and −0.59 V, respectively, by Mott–Schottky analysis.