Deposition duration effects on electrodeposited ZnTe thin films: material properties and device application potential

Journal article, 2026

The effect of deposition duration on the material properties of ZnTe thin films synthesized using the potentiostatic electrodeposition technique and their potential for electronic device applications was investigated in this study. ZnTe films with thicknesses of approximately 100 nm, 220 nm, and 400 nm were successfully deposited at durations of 15, 30, and 60 min, respectively, using an aqueous electrolyte of zinc sulphate heptahydrate (ZnSO₄·7H₂O) and tellurium dioxide (TeO₂) as sources of Zn²⁺ and Te⁴⁺ ions. Structural, morphological, optical, compositional, and electrical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible (UV–Vis) spectroscopy, energy dispersive X-ray spectroscopy (EDX), capacitance–voltage (C–V), and current–voltage (I–V) measurements. The XRD results showed that crystallinity improved with longer deposition duration, while the SEM revealed that grain size increased from ∼90 nm to ∼380 nm. UV–Vis measurements revealed a decrease in optical band gap from 2.60 eV to 2.00 eV as deposition time increased from 0.25 to 1.00 h. The electrical measurements of the ZnTe thin films indicated a moderate doping density and resistivity value in the order of 10⁴ Ωcm. The findings suggest that ZnTe forms a promising hetero-junction partner with CdS for solar cell fabrication. The solar cell parameters obtained were an open-circuit voltage (Voc) of 0.48 V, a short-circuit current density (Jsc) of 19.7 mA cm⁻², a fill factor (FF) of 0.46 and device efficiency of 4.35%. These parameters were obtained for ZnTe thin films deposited at 60 min and treated with CdCl₂ in the cell structure, highlighting the device application potential of ZnTe films deposited under optimised duration.