Nanoscale Defect Engineering and the Resulting Effects on Domain Wall Dynamics in Ferroelectric Thin Films

Abstract

Defect engineering is one of the cornerstones of the modern electronics industry. Almost all electronic devices include materials that have been doped by ion bombardment. For materials where crystallinity is essential, such as ferroelectrics, defect type and concentration can vastly influence properties and are often used to optimize device performance. This study shows a method to effectively control the density and position on the nanoscale of defect sites in thin films of Pb(Zr,Ti)O3 via focused ion beam microscopy. This allows for exceptional clarity of observation of the role of defects in nucleation, polarization switching, and domain wall interaction through investigation with piezoresponse force microscopy and transmission electron microscopy, adding insight to accepted but seldom‐demonstrated facts on defect‐induced effects. This nanoscale defect engineering can be used as a tool to control material properties, and furthermore, a route is demonstrated toward a practical application.

Out‐of‐Plane Polarization Control in Monoclinic Ferroelectrics CuInP 2 S 6 via In‐Plane Electric Field

“…It is found that BiFeO 3 and PbZr 0.4 Ti 0.6 O 3 rely on multiple nucleation sites (≈15 um 2 ) due to the energetically favorable conditions at defects and domain walls, driven by displacive atomic movements. [32][33][34][35] In contrast, our experiment shows a single nucleation site (≈1/25 um 2 ) of CIPS. Previous research by He et al [30] reveal that domain wall motion and nucleation in CIPS demand comparable energy levels.…”

Nanoscale Doping and Its Impact on the Ferroelectric and Piezoelectric Properties of Hf0.5Zr0.5O2

“…In the region of the post-annealing implantation of the Ga ions, as expected, a simple pinning of domains was observed during the capacitor switching (Figure 3g,h). This result was consistent with the decrease in the measured switchable polarization (Figure 2a), and it was in line with a similar experiment on defect engineering in a ferroelectric PZT film [26].…”

“…We explored the effect of introducing defects into ferroelectric HZO on its ferroelectric properties, both locally and area-averaged. The testing of the homogeneously modified HZO revealed a deterioration in the measured switchable polarization of the capacitors with the postcrystallization implantation of the Ga ions (Figure 2a), which was in line with the results for the PbZr 0.1 Ti 0.9 O 3 (PZT) [26].…”

Nanoscale Tailoring of Ferroelectricity in a Thin Dielectric Film

“…This result confirms the existence of a built-in electric field, probably originating from the flexoelectric effect of the electrical coupling to a mechanical strain gradient. Strain gradient is expected due to gradient in Ga concentration across the HfO 2 film, which was simulated in our work (Supporting Information, Section S1) and reported for Ga implantation in PZT thin films . Flexoelectricity is a property of a dielectric material whereby it exhibits a spontaneous electrical polarization induced by a strain gradient.…”