Abstract:
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 Na2S2O3
and 0.1 mol/L ZnSO4
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.
