Characterization of dielectric nanocubes ordered structures fabricated by solution self-assembly process

Ordered structures of barium titanate (BT) nanocubes, strontium titanate (ST) nanocubes and BT-ST nanocube mixture were directly fabricated on Si and Pt-coated Si substrates using a colloidal solution assembly method inspired by convection self-assembly. BT/ST alternating layered structure was also fabricated by repeating the self-assembly process several times. The microstructure of the self-assembled structures was observed using field emission scanning electron microscopy (FE-SEM) and scanning probe microscopy (SPM). It was revealed that nanocubes were arranged with various degrees of ordering to develop monolayer regions at the surface of the substrates. The crystallographic phase and orientation of the assembly consisting of BT and ST nanocubes were evaluated by X-ray diffraction analysis. The (100) and (200) diffractions of BT and ST were observed and no other diffractions were observed. The BT and ST nanocubes had a {100} face and were arrayed orderly with their faces parallel to the surface of the substrates. The piezoresponse properties obtained by scanning probe microscopy (SPM) indicated that the heterointerface between BT and ST nanocubes would introduce an anomaly in piezoelectric properties.