Low-temperature crystalline lead-free piezoelectric thin films grown on 2D perovskite nanosheet for flexible electronic device applications
lead-free piezoelectric thin films, low-temperature-deposition process, 2D nanosheet seed-layers, polymer substrates
A monolayer of Sr2Nb3O10 (SNO) is deposited on the Pt/Ti/SiO2/Si (Pt-Si) or Pt/Ti/polyimide (Pt-PI) substrate by using the Langmuir-Blodgett method and employed as a seed-layer for the growth of a crystalline (Na1−xKx)NbO3 (NKN) film at 350 °C. The crystalline NKN film is grown along the  direction on the SNO/Pt-Si (or SNO/Pt-PI) substrate. Due to the presence of oxygen vacancies in the SNO seed-layer, the NKN film exhibits low ferroelectric properties and large leakage current. To ameliorate these properties, the SNO/Pt-Si substrate is annealed in a 50 Torr oxygen atmosphere at 300 °C, which removes the oxygen vacancies. Consequently, the NKN film deposited on this substrate exhibits promising electrical properties, namely a dielectric constant of 278, dissipation factor of 1.7%, a piezoelectric constant of 175 pm·V−1, and a leakage current density of 6.47 × 10−7 A·cm−2 at −0.2 MV·cm−1. Similar electrical properties are obtained from the NKN film grown on the flexible SNO/Pt-PI substrate at 350 °C. Hence, the NKN films grown on the SNO seed-layer at 350 °C can be applied to electronic devices with flexible polymer substrates.
Tsinghua University Press
Jong-Hyun Kim,Sang Hyo Kweon,Sahn Nahm, Low-temperature crystalline lead-free piezoelectric thin films grown on 2D perovskite nanosheet for flexible electronic device applications. NanoRes.2019, 12(10): 2559–2567