Semchenko Alina V, Sidsky Vitaly V, Bdikin Igor, Gaishun Vladimir E, Kopyl Svitlana, Kovalenko Dmitry L, Pakhomov Oleg, Khakhomov Sergei A, Kholkin Andrei L
Faculty of Physics and Information Technology, Francisk Skorina Gomel State University, 246019 Gomel, Belarus.
TEMA, Department of Mechanical Engineering, University of Aveiro, 3810-193 Aveiro, Portugal.
Materials (Basel). 2021 Mar 30;14(7):1694. doi: 10.3390/ma14071694.
Pure BiFeO (BFO) and doped BiLaFeO (BLFO) thin films were prepared on Pt/TiO/SiO/Si substrates by a modified sol-gel technique using a separate hydrolysis procedure. The effects of final crystallization temperature and La doping on the phase structure, film morphology, and nanoscale piezoelectric properties were investigated. La doping and higher crystallization temperature lead to an increase in the grain size and preferred (102) texture of the films. Simultaneously, a decrease in the average effective piezoelectric coefficient (about 2 times in La-doped films) and an increase in the area of surface non-polar phase (up to 60%) are observed. Phase separation on the films' surface is attributed to either a second phase or to a non-polar perovskite phase at the surface. As compared with undoped BFO, La-doping leads to an increase in the average grain size and self-polarization that is important for future piezoelectric applications. It is shown that piezoelectric activity is directly related to the films' microstructructure, thus emphasizing the role of annealing conditions and La-doping that is frequently used to decrease the leakage current in BFO-based materials.
采用改进的溶胶 - 凝胶技术，通过单独的水解程序，在Pt/TiO/SiO/Si衬底上制备了纯BiFeO（BFO）和掺杂BiLaFeO（BLFO）薄膜。研究了最终结晶温度和La掺杂对相结构、薄膜形貌和纳米级压电性能的影响。La掺杂和较高的结晶温度导致薄膜的晶粒尺寸增大和择优（102）织构。同时，观察到平均有效压电系数降低（在La掺杂薄膜中约降低2倍），表面非极性相面积增加（高达60%）。薄膜表面的相分离归因于表面的第二相或非极性钙钛矿相。与未掺杂的BFO相比，La掺杂导致平均晶粒尺寸和自极化增加，这对未来的压电应用很重要。结果表明，压电活性与薄膜的微观结构直接相关，从而强调了退火条件和La掺杂的作用，La掺杂常用于降低基于BFO的材料中的漏电流。
