TITLE:
Synthesis and Characterization of Metal Organic Chemical Vapour Deposited Chromium Doped Zinc Oxide Thin Film for Gas Sensing Applications
AUTHORS:
Olumide Oluwole Akinwunmi, Olakunle A. Akinwumi, Johnson Ayodele O. Ogundeji, Adetokunbo Temitope Famojuro
KEYWORDS:
Zinc Oxide, Thin Films, Metal Organic Chemical Vapour Deposition, Gas Sensors
JOURNAL NAME:
Materials Sciences and Applications,
Vol.9 No.10,
September
29,
2018
ABSTRACT: Chromium (Cr) doped Zinc oxide ZnO thin films were deposited onto glass
substrates by Metal Organic Chemical Vapour Deposition (MOCVD) technique with
varying dopant concentration at a temperature of 420°C. The effect of the
chromium concentration on morphological, structural, optical, electrical and
gas sensing properties of the films were investigated. The scanning electron
microscopy results revealed that the Cr concentration has great influence on the crystallinity, surface smoothness and grain
size. X-ray diffraction (XRD) studies shows that films were polycrystalline in
nature and grown as a hexagonal wurtzite structure. A direct optical band
energy gap of 3.32 to 3.10 eV was obtained from the optical
measurements. The transmission was found to decrease with increasing Cr doping
concentration. Rutherford Backscattering Spectroscopy (RBS) analysis also demonstrates that Cr ions are substitutionally incorporated into ZnO. I-V characteristic
of the film shows a resistivity ranges from 1.134 × 10-2 · cm to 1.24
× 10-2 · cm at room temperature. The gas sensing response of the
films were enhanced with incorporation of Cr as a dopant with optimum operating
temperature around 200°C.