ABSTRACT
The optical and structure properties of Cadmium oxide (CdO) thin film prepared by
electrochemical deposition method at different times (15, 30 and 60) min were investigated in this
paper. Results of optical Transmission, absorption, reflection spectra, optical conductance, refractive
index, extension coefficient, real and imaginary dielectric constants studies are reported. The optical
transmittance of the CdO thin film which formed at room temperature was 20% at wavelength ≈350
nm then increases to 60% at wavelength ≈1100 nm for thin film of CdO. The band-gap was also
calculated from the equation relating absorption coefficient with the wavelength. The energy band gap
changes from 2.3eV (Bulk CdO) to 2.45eV (CdO thin film). The plotted graphs show the optical
characteristics of the film which varied with the wavelength and the photon energy. The optical
conductance and band-gap indicated that the film is transmitting within the visible range. The
dielectric constant and optical conductance of the film initially decreases slowly with increase in
photon energy. The extinction coefficient and refractive index of the films also evaluated, which
affected with the change in transmittance. The structure of synthesised CdO thin film was analyzed by
X-ray diffraction XRD which revealed that the CdO thin film are polycrystalline and have several
peaks of cubic face structure. The crystallite size, dislocation density, microstrain and number of
dislocations of the thin film were calculated and listed.
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