Zinc oxide-silica (ZnO/SiO 2 = 20:80, molar ratio) nanocomposites consisting of ZnO nanoparticles embedded in a dielectric matrix were prepared by a sol-gel technique (spin coating). Optical transmittance, Raman effect and photoluminescence measurements of the composites indicated effective capping of the ZnO nanoparticles (radii 1.4-1.5 nm) in the host showing practically no variation of particle size with the post-deposition-annealing treatments. The blue shift of the band gap (4.23-4.29 eV) from that of bulk ZnO (3.3 eV) indicated strong carrier confinement for samples annealed at T≤773 K. Highly intense UV emission (approx. 4.2 eV) at room temperature could be obtained by annealing the composites in static oxygen atmosphere, while the visible defect-related luminescence (approx. 2.62 and 2. 43 eV) could be reduced, resulting in a high intensity ratio (approx. 27) of the two.
- Optical properties
- Zinc oxide