Optical properties of sol-gel synthesized calcium doped ZnO nanostructures

Optical properties of Ca doped ZnO nanoparticles prepared at room temperature through wet chemical method have been investigated. X-ray diffraction studies show that particles are crystalline in nature and doping did not induce impurity phases. Optical absorption measurements show an absorption peak at similar to 372 nm which is due to excitonic absorption of the ZnO. Photoluminescence studies reveal a broad emission at an excitation wavelength of 335 nm and the bands are attributed to near band edge emission, oxygen vacancies, surface dangling bonds and zinc interstitials. Incorporating Ca2+ induces reduction in near band edge emission and there is an enhancement in the oxygen vacancy peaks which are attributed to the shape changes in the nanoparticles. (C) 2011 Elsevier B.V. All rights reserved.