| Abstract: | ZnO crystals were synthesized from basic aqueous solutions including zincate ions stabilized with triethanolamine (N(C2H4OH)3, teaH3) by heating at 60°C. The influence of the basicity of the solutions on the morphology of the ZnO crystals was examined. The aqueous solutions were prepared using ZnSO4·7H2O, N(CH3)4OH (TMAOH), and teaH3 as a zinc source, a base, and a stabilizer, respectively, at a zinc concentration of 0.2 M at a teaH3 / Zn molar ratio of 4. Clear solutions were obtained at a molar ratio of TMAOH / Zn ≥ 3.0. When the clear solutions, in which glass or polyester substrates were placed, were heated at 60°C, agglomerates of ZnO crystals were deposited on the substrates in the TMAOH / Zn range from 3.0 to 3.6. With increasing the TMAOH / Zn ratio, the shape of the resulting ZnO crystals changed from a short asymmetric column with a hexagonal flat edge and a rounded one, through a rocket‐like shape formed by intergrowth, to a hexagonal rod. Although no films of ZnO were formed, ZnO crystals with different shapes were synthesized. When the glass substrates pre‐coated with a ZnO thin film by a sol‐gel method were used, highly oriented, dense ZnO films were formed. The films consisted of rod‐like crystals aligned normal to the substrate surface. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) |
