Ferroelectricity and Piezoelectricity of Na 0.5 Bi 0.5 TiO 3 Nanotube Arrays: Implications for Functional Electronic Devices

Piezoelectric and ferroelectric properties of lead-free sodium bismuth titanate Na 0.5 Bi 0.5 TiO 3 (NBT) nanotube arrays were studied using piezoresponse force microscopy. The nanotube arrays prepared by sol filling in the porous anodic aluminum oxide template with an exposure height of 30–55 nm and vertical arrangement demonstrated enhanced piezoelectric properties compared with the other nanotube structures and a large piezoelectric coefficient with regular domain states. We further prepared a metal/NBT nanotube arrays/metal capacitor for the study of ferroelectric and piezoelectric properties. The piezoelectric properties of NBT nanotube arrays were found to be much improved in a capacitor and finite element modeling attributes such improvement to the uniform electric potential distribution from the tip of the nanotube in the capacitor. The improved piezoelectric properties could make NBT nanotube arrays as a promising candidate for piezoelectric nanostructure devices.