| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1488791 | Materials Research Bulletin | 2013 | 9 Pages |
•Fe-doped ZnO films show smaller crystallinity with crystallite size: 15–26 nm.•Optical band gap in ZnO films decreases on Fe doping.•Fe-doped films exhibit the normal dispersion for the wavelength range 450–600 nm.•PL spectra of the Fe-doped films show quenching of the broad green-orange emission.•Acetone response of the Fe-doped films increases considerably at 300 °C.
The ZnO thin films (undoped and Fe-doped) deposited by chemical spray pyrolysis technique have been analyzed by X-ray powder diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Results show that all the films possess hexagonal wurtzite structure of zinc oxide having crystallite sizes in the range 15–36 nm. On 1 at% Fe doping, the surface roughness of the film increases which favors the adsorption of atmospheric oxygen on the film surface and thereby increase in the gas response. Optical studies reveal that the band gap decreases due to creation of some defect energy states below the conduction band edge, arising out of the lattice disorder in the doped films. The refractive index of the films decreases on Fe doping and follows the Cauchy relation of normal dispersion. Among all the films examined, the 1 at% Fe-doped film exhibits the maximum response (~72%) at 300 °C for 100 ppm concentration of acetone in air.
Graphical abstractAll the films are found to be polycrystalline ZnO possessing hexagonal wurtzite structure. The intensities of all the peaks are diminished strongly in the Fe-doped films, indicating their lower crystallinity as compared to the undoped ZnO film. The average crystallite size decreases from 35.21 nm (undoped sample) to 15.43 nm (1 at% Fe-doped sample).Figure optionsDownload full-size imageDownload as PowerPoint slide
