In situ high temperature XRD studies of ZnO nanopowder prepared via cost effective ultrasonic mist chemical vapour deposition
Ultrasonic mist chemical vapour deposition (UM-CVD) system has been developed to prepare ZnO nanopowder. This is a promising method for large area deposition at low temperature inspite of being simple, inexpensive and safe. The particle size, lattice parameters and crystal structure of ZnO nanopowder are characterized by in situ high temperature X-ray diffraction (XRD). Surface morphology of powder was studied using transmission electron microscopy (TEM) and field emission electron microscope (FESEM). The optical properties are observed using UV-visible spectrophotometer. The influence of high temperature vacuum annealing on XRD pattern is systematically studied. Results of high temperature XRD showed prominent 100, 002 and 101 reflections among which 101 is of highest intensity. With increase in temperature, a systematic shift in peak positions towards lower 2θ values has been observed, which may be due to change in lattice parameters. Temperature dependence of lattice constants under vacuum shows linear increase in their values. Diffraction patterns obtained from TEM are also in agreement with the XRD data. The synthesized powder exhibited the estimated direct bandgap (Eg) of 3.43 eV. The optical bandgap calculated from Tauc’s relation and the bandgap calculated from the particle size inferred from XRD were in agreement with each other.
KeywordsHigh temperature XRD ZnO nanopowder ultrasonic mist chemical vapour deposition
Unable to display preview. Download preview PDF.
- Cullity B D 1970 Elements of X-ray diffraction (Addison-Wesley) p. 102Google Scholar
- Lamber R, Wetjen S and Jaeger N I 1995 Phys. Rev. B51 10968Google Scholar
- Nanda K K, Kruis F E and Fissan H 2002 Phys. Rev. Lett. 89 256103Google Scholar
- Tauc J (ed.) 1974 Amorphous and liquid semiconductor (New York: Plenum Press)Google Scholar
- Wood V E and Austin A E 1975 Magnetoelectric interaction phenomena in crystals (London: Gordon and Breach)Google Scholar