Influence of precursor concentration on structural, morphological and electrical properties of spray deposited ZnO thin films

Crystal Research and Technology (Impact Factor: 1.12). 06/2011; 46(7):685. DOI: 10.1002/crat.201000672

ABSTRACT Nanostructured ZnO thin films were coated on glass substrate by spray pyrolysis using Zinc acetate dihydrate as precursor. Effect of precursor concentration on structural, morphological, optical and electrical properties of the films was investigated. The crystal structure and orientation of the ZnO thin films prepared with four different precursor solution concentrations were studied and it was observed that, the prepared films are polycrystalline in nature with hexagonal wurzite structure. The peaks are indexed to (100), (002), (101), (102) and (110) planes. Grain size and texture coefficient (TC) were calculated and the grain size found to increase with an increase in precursor concentration. Presence of Zn and O elements was confirmed with EDAX spectra. Optical absorption measurements were carried out in the wavelength region of 380 to 800 nm and the band gap decreases as precursor concentration increases. The current-voltage characteristics were observed at room temperature and in dark. It was found that for the films deposited at four different precursor
concentrations, the conductivity improves as precursor concentration increases. As trimethylamine (TMA) is a good marker for food quality discrimination, sensing behavior of the films at an optimized operating temperature of 373 K, towards various concentrations of (TMA) was observed and reported.

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    ABSTRACT: Undoped and Doubly (Magnesium + Fluorine) doped zinc oxide (ZnO:Mg:F) thin films with different Mg doping levels (4, 8, 12 and 16 at.%) and constant F doping level (20 at.%) were fabricated by employing a simplified spray pyrolysis technique. The antibacterial and certain physical properties of the films were studied as a function of Mg doping level. All the films exhibited hexagonal wurtzite structure with preferential orientation along the (002) plane. A lesser electrical resistivity was achieved in the present study than earlier reports of ZnO:Mg films thanks to the simultaneous doping of F with Mg in ZnO films. From the optical studies, it was observed that, all the films showed good transparency (≈85 %) with significant enhancement in the optical band gap with Mg doping level. The obtained PL spectra were well corroborated with the structural and optical studies. Further, it was also found that the antibacterial activity of doubly doped ZnO films was enhanced remarkably by the increasing incorporation of Mg concentration.
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Aug 6, 2014