Investigation of the Effect of Deposition Time and Annealing on the Structural and Optical Properties of Chemically Deposited ZnS Thin Films
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Date
2023
Journal Title
Journal ISSN
Volume Title
Publisher
Deanship of Research & Graduate Studies, Yarmouk University, Irbid, Jordan
Abstract
The Chemical bath deposition (CBD) technique was successfully used to
deposit ZnS thin films. The effects of deposition time and annealing on the structural and
optical properties of the obtained thin films were investigated by X-ray diffraction (XRD),
and UV-Vis spectrophotometer, respectively. The XRD pattern for the as-deposited ZnS
thin films deposited for 30 min showed three peaks at 2θ values of 28.75o
, 48.05o
, and
56.47o
corresponding to (111) (main peak), (220), and (311) reflection planes, indicating
cubic structure. Comparing these peaks with that of the films prepared for 60 min, the latter
have narrower widths, are more intense, sharper, and produce another weak peak at 2θ
angle of 33.51o. Post-annealing treatment results in even more intense and sharper peaks,
with their width narrowing further, causing an improvement in the crystallinity. The grains
detected from the SEM micrograph are well-defined with spherical shapes of varying sizes.
The grain shape changes after annealing due to coalescence of the grains. According to the
EDX result, Zn and S were present in the prepared film. The as-deposited films showed a
maximum transmittance of 82.1% at the visible region, which increased to 89.2% after
annealing. The optical energy band gap was found to be in the ranges of 3.58 - 3.75 eV and
3.41 - 3.73 eV for the as-deposited and annealed films, respectively, signifying that the
energy band gap decreases with annealing.
Description
Keywords
Chemical bath deposition, Zinc sulphide, Optical properties, Annealing, Thin films, Deposition time