Abstract
ZnO nanostructures were synthesized by a proteic sol-gel method, using zinc nitrate hexahydrate and gelatin as precursors. Size and shape evolution of ZnO nanostructures were achieved by annealing temperature in the range 250-1000 oC. The crystalline structure, morphology and optical properties of the ZnO nanoparticles were characterized by X-Ray Diffraction (XRD), Raman Spectroscopy (RS), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and room temperature Photoluminescence (PL). The result of structural characterization shows the formation of platelets and nanorods in the micro-scale and ZnO nanostructures with high quality hexagonal wurtzite crystal. Sharp peaks in RS after annealing temperature, related to wurtzite structure, were observed corroborating with XRD and TEM measurements. Room temperature PL spectra showed two contribution bands which peaked at ~380 nm, originating from the recombination of free excitons, and ~520 nm corresponding to the impurities and structural defects, like oxygen vacancies and zinc interstitial. The effects of annealing temperature in the structural and optical properties are detailed and the results compared among the experimental techniques. The high quality of the samples obtained by an alternative organic precursor method opens a low-cost route to technological applications of zinc oxide.
Highlights
Zinc oxide (ZnO) is an important semiconductor material with a direct wide band gap (3.37 eV) and a large exciton binding energy at room temperature1
The samples submitted to thermal degradation were annealed at temperatures between 450 oC and 1000 oC in order to study the thermal evolution of the material
In order to obtain more detailed information about ZnO nanoparticles, Transmission Electron Microscopy (TEM) analysis were conducted on this sample
Summary
Zinc oxide (ZnO) is an important semiconductor material with a direct wide band gap (3.37 eV) and a large exciton binding energy at room temperature (about 60 meV). ZnO has attracted much attention due to its strong commercial importance, such as in solar energy conversion, photocatalysis, ultra-violet lasers, and gas sensors. ZnO has attracted much attention due to its strong commercial importance, such as in solar energy conversion, photocatalysis, ultra-violet lasers, and gas sensors5 In this sense, ZnO has been postulated as a quasi-one-dimensional material with unique properties making it suitable for a series of applications. Nanostructured ZnO have been synthesized by distinct methods, such as ultrarapid sonochemical, hydrothermal synthesis, microwave assisted irradiate, sol-gel, and aqueous solution methods. Nanostructured ZnO have been synthesized by distinct methods, such as ultrarapid sonochemical, hydrothermal synthesis, microwave assisted irradiate, sol-gel, and aqueous solution methods11 In all these cases, the materials properties are strongly dependent on the synthesis parameters.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
