High resolution scanning probes of ferroelectric thin films.

摘要

Advances in materials growth techniques enable precise control over the growth of novel functional materials such as ferroelectric thin films, which are interesting from both a physics and applications perspective. Physical properties of ferroelectric thin films differ a lot from their bulk counterparts, mainly due to the lattice mismatch at the film-substrate interface and differential thermal contraction experienced during growth. Those property anomalies are confined to a narrow range usually thinner than 1000 nm. High-resolution probes are important for understanding the spatial and temporal properties of these systems. We have developed mechanical and optical scanning probe techniques and used them to investigate various strain-engineered ferroelectric thin films. These optical and scanning probe techniques are designed to detect ferroelectric domain dynamics. Our experimental results either give direct evidence to verify material functionality, or reveal the relation between nano-scale dynamics to their macroscopic properties.