Size-Dependent Selective Etching Mechanism: Cavity Formation on Barium Titanate Nanocubes

We report here the selective formation of nanosized cavities on barium titanate (BaTiO3) nanocubes through a simple acid etching route in hydrothermal environment. Microstructural analysis reveals that the etching process is size dependent with small cavity preferentially formed on the nanocubes greater than a characteristic length of similar to 60 nm. A dislocation assisted etching mechanism is proposed to account for the experimental observations and discussed on the basis of the classical dislocation theory. This simple method could be extended to other perovskites for fabricating novel and complex ferroelectric nanostructures.