Effect of Concentration on Morphological, Optical and Electrical Properties of Copper Doped Zinc Oxide Thin Films Deposited by Electrostatic Spray Pyrolysis (ESP) Technique | Chapter 03 | New Advances in Materials Science and Engineering Vol. 1
Pure zinc oxide (ZnO) and copper (Cu)
doped ZnO thin films were synthesised from the precursor’s concentrations (zinc
acetate and copper acetate) onto glass substrate via electrostatic spray
pyrolysis (ESP) deposition technique at 350°C in air ambient with different Cu
doping concentrations (0%, 5%, 10%, 15% and 20%). The thin films were analysed
with regards to its morphological, optical, and electrical properties before and
after annealing. The results indicate that the annealing of the thin films leads
to improved surface morphology and better crystallinity quality. Nanofibers
were observed around the nucleation centre in the pure ZnO thin films. The
absorbance was recorded in the wavelength range of 230 nm to 1100 nm, and the
optical transmission of the films was found to increase for increasing doping
concentration of Cu up to 370 nm and then decreased for higher wavelengths.
ZnO:Cu films displayed high optical transparency which is around 86% - 98% in
the visible and infrared regions but minimum in the ultraviolet region. The
band gap energy value of the pure ZnO films was found to be 3.20 eV, whereas
the doped films revealed a continuous decreases for higher doping of Cu
concentration, reaching a value of 2.66 eV. The refractive index of the films significantly
changes with the deposition parameter and increases sharply from 1.4597 to
1.7865 and the highest electrical resistivity was found to be 8.83 μm, and the
lowest optical conductivity of 0.113 MƱm-1 was observed in the films with 20%
Cu doped film, which indicates that the deposited films are highly suitable for
photovoltaic cells and other optoelectronic device applications.
Author(s) Details
D. O. Samson
Department of Physics,
University of Abuja, P.M.B 117, Abuja, Nigeria and School of Physics, Universiti
Sains Malaysia, 11800 USM, Gelugor, Penang,
Malaysia.
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