Bi4Ti3O12 Nanowall Growth Driven by Anisotropic Growth Rate and Size Control

Ferroelectric and piezoelectric Bi4Ti3O12 was epitaxially grown on TiO2(101) with a(b)-axis orientation by pulsed laser deposition (PLD). Owing to the strong growth anisotropy indigenous to bismuth-layered perovskites including Bi4Ti3O12, it grew rapidly along the a-and b-axes and slowly along the c-axis. Therefore, at low deposition temperatures below 700 degrees C, Bi4Ti3O12 nuclei did not merge with each other along the c-axis during the growth, which resulted in the formation of the nanowall-like structure. It was found that the width of nanowalls decreased with decreasing deposition temperature, which implies that the surface diffusivity of PLD species plays a role in changing the width of nanowalls. It was also found that the interval of nanowalls can be effectively controlled by adjusting the oxygen pressure during the deposition. (c) 2013 The Japan Society of Applied Physics