Surface Controlled Growth of Thin-Film Strontium Titanate Nanotube Arrays on Silicon

Abstract

We demonstrate the vertical self-organized growth of thin-film SrTiO3 (STO) nanotube arrays (NTAs) on SiO2 substrate. The surface morphology and crystal orientation of the grains at the exterior wall of the backbone TiO2 nanotube arrays were found to play an important role in the growth rate as well as the final morphology of the STO NTAs. A formation mechanism is proposed that involves nucleation of SrTiO3 nanocubes through a semitopochemical route followed by a self-assembly process resulting from the Ostwald-ripening-assisted oriented attachment of SrTiO3 nanocubes. It was shown that under appropriate reaction kinetics the nanotube architecture of the overall template can be maintained to form STO NTAs. The application of this novel platform enables a controlled and efficient mass fabrication of STO NTAs on widely used inexpensive silicon substrates, which can potentially lead to full integration with electronics in the near future.