Local C-V mapping for ferroelectrics using scanning nonlinear dielectric microscopy

摘要

Detailed analysis of local polarization switching will promote the further development of a wide range of applications using ferroelectrics. Here, we propose a local C-V mapping technique using scanning nonlinear dielectric microscopy (SNDM) that enables visualization of dynamic ferroelectric switching behavior in real space. Using this method, C-V butterfly curves characteristic of ferroelectrics can be measured on a scanning probe microscopy platform with nanoscale resolution by virtue of the high capacitance-detection sensitivity of SNDM. This provides real-space mapping of the net switchable polarization, the switching voltage, and the local imprint with a short measurement time (e.g., 10 min or less for 256 × 256 pixels). Furthermore, the proposed method will be useful for study of the electric-field response of domain walls. In this paper, we present some examples of experiments with LiTaO_3 single crystals and HfO_2 -based ferroelectric thin films and give an overview of what kind of evaluation is possible with the local C-V mapping technique.