Effects of Deposition Time and Temperature on the Optical properties of Chemically Deposited ZnO thin film
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Date
2024
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Federal University of Kashere-Nigeria
Abstract
Zinc Oxide thin film was successfully deposited using chemical bath deposition method. The
optical and morphological measurements were reported using ultra-violet visible
spectrophotometer and Scanning Electron Microscope respectively. The elemental composition
was investigated using Energy Dispersive X-ray and the result showed peaks corresponding to
the two main elements (Zinc and Oxygen) only, signifying the purity of the deposited films.
The optical property was observed to depend on the deposition times and temperature. The
films’ percentage transmittance was observed to reduce with increasing deposition time, with
the film sample deposited for 30 min exhibiting the highest percentage transmittance of 82.7%
among the samples deposited for the same temperature. Reduction in the deposition
temperature to 60 oC increased the films’ transmittance to the highest value of 84.8%. The direct
band gap energy values increased from 3.47 to 3.51 eV when the deposition time was increased
from 30 to 60 min and reduced to 3.46 eV when the deposition temperature was reduced from
70oC to 60oC. Urbach energy was deduced from its exponential relationship with photon energy
and the result showed that the value increase with increasing deposition time but decreased with
deposition temperature. These results from this study revealed that ZnO thin film possessed the
required properties suitable for its application as transmission conducting oxide in solar cells
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Keywords
Band gap energy, Urbach energy, Chemical bath deposition method, Transmittance, SEM