Synthesis of Anatase Nanosheets with Exposed (001) Facets via Chemical Vapor Deposition

Abstract

High-density anatase titanium dioxide (TiO2) nanosheets with high-energy (001) surfaces were successfully synthesized on silicon and silicon coated substrates via chemical vapor deposition (CVD). Randomly oriented nano sheets and aligned nanosheets were synthesized depending upon gas flow conditions, and different growth mechanisms were proposed for each structure. To prevent anatase-to-rutile phase transformation, the substrate temperature was maintained as low as 450 degrees C, and instead, hydrogen (H-2) autoignition was induced to provide additional heat and pressure to the substrates in a moment It is obvious that silicon vapor can suppress the growth of anatase crystals into a [001] orientation, resulting in the formation of two-dimensional (001) nanosheets. This strategy of passivating specific crystal facets using silicon can be simply extended to the tailoring of other nanosheet structures that are impossible to be obtained via general crystal growth approaches.