Morphological and Photoelectrochemical Properties of ALD TiO[sub 2] Films

films were grown by atomic layer deposition (ALD) at with and as gas sources. The relationships among deposition temperature, microstructure, and photoelectrochemical properties were investigated. The results showed that the crystalline form is anatase at deposition temperatures of and is a mixture of anatase and rutile at . The grain size changed with the deposition temperature and had a minimum at around . The potential sweep voltammograms demonstrated that the photoelectrochemical properties of these films were deteriorated by either the high defect density or the small grain size, or the existence of rutile phase. In order to modify the morphological properties of ALD films, a two-stage ALD with first stage for a nucleation layer and second stage for stress release and grain growth was proposed. Expectedly, the photoelectrochemical properties were significantly improved by this approach.