Construction of TiO2/Si heterostructure by nanoepitaxial growth of anatase-type TiO2

Abstract

Nearly defect-free interfaces can be formed using two lattice-matched semiconductors and nanoepitaxial growth methods that can be controlled at the atomic level. In this work, the nanoepitaxy of anatase-type TiO2 on crystalline silicon substrates for fabricating TiO2/Si heterogeneous interface is demonstrated by combining self-assembly and hydrothermal methods. Solid-phase nanoepitaxy is formed in this heterogeneous interface according to the crystal type and crystal lattice matching between anatase-type TiO2 and crystalline silicon. X-ray diffraction (XRD) and crystal symmetry indicate that the nanoepitaxy growth of anatase-type TiO2 on the Si (001) plane is (001) plane. Anatase-type TiO2 atoms are directly connected with Si atoms. Inconsiderable SiO2 exists between anatase-type TiO2 and crystalline silicon substrate. These interfaces could promote the transfer rate of carriers and decrease the recombination rate of hole-electron pairs. This evidence is confirmed by comparison with rutile-type TiO2, which could not be grown on Si substrate due to the mismatching crystal lattice parameter. The rutile-type TiO2 can be removed easily in ultrasonic condition.