A Systematic Study of Solution Aging Time Impact on Surface Morphology of Sol-Gel Derived ZnO Thin Films
Pure ZnO thin films were spin coated on glass substrates using 0.5M Zinc acetate dihydrate precursor solution and then annealed at 500°C for 2h in air to get good quality thin films. The effect of sol-aging time, from as-synthesized to 4week aged, on microstructure and morphology of ZnO thin films was investigated. X-ray diffraction spectra revealed the polycrystalline wurtzite structure preferentially oriented along the (002) polar plane with variable peak intensity. AFM analysis exposed an asymmetrical cyclic morphology transition with sol-aging time from comparatively smooth surfaces with small spherical particles to a rigid wrinkle network of a high rms surface roughness value of at～42.4nm which finally untied and evolved as homogeneous surface of uniform grain distribution after 4 weeks of aging time. The minimum surface roughness of 1.6nm was obtained for the film prepared from 24h aged solution.
Yuhang Yang, Xilong Qu, Yiping Luo and Aimin Yang
B. Shahzad and Y. Qi, "A Systematic Study of Solution Aging Time Impact on Surface Morphology of Sol-Gel Derived ZnO Thin Films", Advanced Materials Research, Vol. 216, pp. 271-277, 2011