Fabrication and characterization of vertically well-aligned PbTiO3/TiN core-shell nanotube arrays

Abstract

“There’s plenty of room at the bottom’’, the 1959 dream statement of the legendary Richard Feyn-man has been realized in less than half a century by consistent efforts and significant contributions from the scientific community across the globe. Three decades later Feynman’s vision has become the greatest scien-tific frontier of the century. It opened a new field of “Nanostructures” having dimensions of about 1 to 100 nm. Advances in science and technology of ferroelectrics the last decade have resulted in the development of nanoscale ferroelectric structures and devices (< 100 nm). Scaling of the device dimensions to the range where ferroelectrics start to show pronounced size effects has emphasized the importance of studies of ferroelectric properties at the nanoscale. The 1D nanostructures of ferroelectrics has been much less studied compared to nanoparticles and thin films. Firstly, we fabricated highly ordered and well aligned TiN nanotube arrays using a template-assisted method with an AAO template and ALD technique. The dimensions and morphology of the TiN nanotube arrays were controlled by adjusting the anodization conditions and number of ALD cycles. The TiN nanotube arrays were well aligned at a low aspect ratio of 10. However, for an aspect ratio of 14, the TiN nanotubes were clustered and bundled together due to the lateral capillary forces between the nanotubes during the air drying process where water was removed. Furthermore, the films consisted of the TiN nanotube array exhibit-ed good ductility. Secondly, the adhesion properties of the flexible TiN nanotube arrays were improved with a Pt sub-strate using a Ti interlayer. Generally, the TiN nanotube arrays that are transferred to a Pt substrate peel off, delaminate, and facet from the substrate due to their poor adhesion properties. However, the TiN nanotube arrays deposited using a Ti interlayer between the TiN nanotube arrays and Pt substrate were attached perfectly to the Pt substrate. T...