Effect of aging time of ZnO sol on the structural and optical properties of ZnO thin films prepared by sol–gel method

• Published in: Applied surface science 2010-05, Vol.256 (14), p.4543-4547
• Main Authors: Li, Yaoming, Xu, Linhua, Li, Xiangyin, Shen, Xingquan, Wang, Ailing
• Format: Article
• Language: English
• Subjects: Aging time; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Materials synthesis; materials processing; Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity); Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Photoluminescence; Physics; Sol-gel processing, precipitation; Sol–gel method; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Transmittance; ZnO thin films
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2010.02.044

In this work, ZnO thin films were prepared by sol–gel method and the effect of aging time of ZnO sol on the structural and optical properties of the films was studied. The structural characteristics of the samples were analyzed by an atomic force microscope and an X-ray diffractometer. The optical properties were studied by a UV–vis spectrophotometer and a fluorophotometer. The results show that the ZnO thin film prepared by the as-synthesized ZnO sol had relatively poor crystalline quality, low optical transmittance in the visible range and relatively weak ultraviolet emission performance. After the as-synthesized ZnO sol was aged for 24 h, the degree of the preferred crystal orientation along the c-axis of the ZnO thin film prepared by this aged sol was improved. At the same time, this film had a very smooth surface with uniform grains and both its visible range transmittance and ultraviolet emission intensity were obviously increased. These results suggest that appropriate aging of ZnO sol is very important for the improvement of structural and optical quality of ZnO thin films derived from sol–gel method.