Publication:
Optical characterization of chemical bath deposition Cd₁₋ₓZnₓS thin films
Optical characterization of chemical bath deposition Cd₁₋ₓZnₓS thin films
Date
2012-01
Authors
M. A. Mahdi
S. K. J. Al-Ani
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Research Projects
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Abstract
Cd₁₋ₓZnₓS thin films prepared by a chemical bath deposition (CBD) method. Cadmium acetate, zinc acetate and thiourea used as a cadmium, zinc and sulfur ions in solution, respectively. Five types of samples were synthesized onto glass substrates with different Cd2+ and Zn2+ sources moralities in alkaline solution (pH=11) and at temperature 80 ºC. The films' thickness was in the range (102-120) nm and most film's thickness decreases while Zn concentration in solution increased. The transmittance of films increased as Zn concentration increased. All films, however, have high transmittance of 65-85% in the wavelength region (500-900) nm, which is high enough for solar cell applications. The energy band gaps of Cd₁₋ₓZnₓS films calculated and their values were (2.24-3.7) eV. The values of the width of the tails of localized states in the forbidden gap of the films obtained form Urbach plots and varied in the range (0.025-0.11) eV. The optical constants such as, extinction coefficient, refractive index, real and imaginary parts of the dielectric constant are found. The dispersion energy Ed and a single-oscillator energy Eo measured from the single oscillator model below the absorption edge are used to calculate the moments of the optical spectra M-1 and M-3.
Description
Keywords
Cd1-xZnxS thin films,
Chemical bath deposition,
Structure composition,
Optical energy gap,
Cd₁₋ₓZnₓS thin films