Thin film formation by oriented attachment of polymer-capped nanocrystalline ZnO

Chemical bath deposition has been introduced as a means to produce films of inorganic substances with low engineering expenditure and close to ambient temperature. Organic additives have been used to control the growth of zinc oxide particles in solution and prevent the formation of the typical rod-like morphology. In the present work an attempt is made to combine these two approaches in order to produce thin films of zinc oxide. In the presence of beta-cyclodextrin, spherical nano-crystalline deposits were obtained from solution; polyethylene glycol induced the formation of nanostructured thin films. With polyvinylpyrrolidone as an additive, uniform films were deposited. The structure of these films was analyzed by X-ray diffraction and transmission electron microscopy, which revealed the presence of domains of locally oriented nanocrystals. A mechanism of oriented attachment is proposed to explain the formation of domained ZnO films.