Using an electroconductive carbon nanotube probe tip in scanning nonlinear dielectric microscopy

A scanning nonlinear dielectric microscope (SNDM), which can be used for detecting the surface and subsurface of ferroelectric polarization with high resolution, has been developed. Contact-mode atomic force microscopy typically uses a metal-coated conductive cantilever tip; however, SNDM imaging resolution declines upon repeated scanning because of the abrasion of the tip in the contact mode. To improve the lateral resolution of the tip, we used an electroconductive carbon nanotube (CNT) probe tip. Using the SNDM with the CNT probe, the ferroelectric domain boundary of stoichiometric lithium tantalate (LiTaO₃) is observed in air at room temperature and the results compared with those obtained using a platinum-coated tip.