Enhanced piezoelectricity of thin film hafnia-zirconia (HZO) by inorganic flexible substrates

Hf0.5Zr0.5O2 (HZO) films are grown on rigid glass and flexible polyimide substrates using non-rapid thermal annealing. Films are comparatively investigated using macroscopic and local probe-based approaches to characterize their ferroelectric and piezoelectric properties. The polarization-electric field (P-E) measurements reveal that the ferroelectric characteristics of these thin films agree with the observed switchable piezoresponse hysteresis loops as well as electrically written, oppositely oriented domains. Moreover, the HZO thin films grown on flexible polyimide substrates display significantly enhanced piezoelectric response in comparison to the films grown on rigid substrates. This effect is likely due to improved domain wall motion caused by the mechanical release of the film-substrate couple. These findings suggest that inherently lead-free HZO thin films on flexible substrates are potential candidate materials for improved piezoelectric applications in wearable devices. Published by AIP Publishing.