All-inorganic transparent Hf_0.85Ce_0.15O₂ ferroelectric thin films with high flexibility and stability

Electronic devices that are transparent and flexible have a wide range of applications in the domains of vital sign parameter monitoring, health management, and so on. Ferroelectric memory is a revolutionary nonvolatile memory that is ideal for data storage and processing in transparent flexible electronic systems. In this study, Ce-doped hafnium oxide ferroelectric thin film is manufactured on mica substrate by the chemical solution deposition with transparent indium tin oxide (ITO) thin films as the bottom electrodes. The transmittance of mica/ITO/Hf_0.85Ce_0.15O₂ thin film is over 80%. The 2P_r of the transparent flexible Hf_0.85Ce_0.15O₂ ferroelectric thin film is increased by about 22.4% and the E_c is reduced by 26.7% compared with those of Hf_0.85Ce_0.15O₂ ferroelectric thin film grown on p+-Si substrate. The transparent flexible Hf_0.85Ce_0.15O₂ ferroelectric thin film can remain keeping good quality when being bent under ±2.5 mm bending radius. Additionally, degradation of polarization, retention, and endurance performance was not obvious even at a bending radius of 5.0 mm after 10⁴ bending cycles. This research provides a new strategy and an important experimental basis for the development and implementation of transparent flexible ferroelectric memories.