Highly crystalline ZnO nanoparticles

Abstract

Highly crystalline, defect free ZnO nanoparticles have been synthesised by the chemical co-precipitation technique. The product sample was characterised by the X-ray diffraction (XRD) and UV-visible absorption spectra. Analysis shows that there is no indication for oxygen vacancies in the as-prepared ZnO nanomaterials. Normally, a green absorption broad band at around 520 nm is observed in the absorption spectrum of ZnO due to oxygen vacancy. This defect is not observed in the present nanomaterial. The shape and size of the prepared nanoparticles were also observed by transmission electron microscope (TEM). The nanoparticles are of semispherical shape having average particle size ∼30 nm. The effect of sonicating time on the morphology of the prepared nanoparticles is also studied. Increasing the sonicating time provides quite spherical well-separated nanoparticles. These remarkable results for producing highly crystalline ZnO nanoparticles with a uniform shapes are quite useful for using them in several applications such as UV light emitting devices and biosensors.