Effects of wall thickness on morphology and structure of lead titanate nanotubes

We report the effects of wall-thickness on the morphology and structure of PbTiO₃ nanotubes (PTO-NTs). The PTO-NTs were fabricated via template-directed growth in conjunction with sol-gel process and spin-coating technique. Wall-thickness was increased from 10 to 70 nm by repeating the process of spin-coating and subsequent pyrolysis. X-ray diffraction patterns showed that the PTO-NTs exhibited a tetragonal-structure. We found that their tetragonality increased from 1.0310 to 1.0487 as wall-thickness increased from 10 nm to 70 nm. Raman spectroscopy revealed that peak positions of E(1TO) phonon corresponding a-axis shifted toward higher frequency due to their residual stress in the PTO-NTs.