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利用溶胶-凝胶法在LaNiO_3/SiO_2/Si衬底上制备了0.7BiFeO_3-0.3PbTiO_3(BFPT7030)薄膜,利用快速退火方式将薄膜分别在空气、氧气流、空气流、氮气流中进行后续退火处理。在空气、氧气流及空气流中退火的薄膜均完全结晶并呈现高度(100)择优取向。而在氮气流中退火的薄膜由于结晶很差,测试不出其电滞回线。空气中退火的BFPT7030薄膜表现出最大的剩余极化及最小的漏电流,Pr为30μC·cm~(-2),而在空气流中退火的BFPT7030薄膜表现出最小的剩余极化(Pr:13μC·cm~(-2))及最大的漏电流。XPS测试结果表明,在空气、氧气流及空气流中退火的BFPT7030薄膜中Fe~(3+):Fe~(2+)分别为2.09:1,1.65:1及1.5:1。而在氧气流及空气流中退火的BFPT7030薄膜中Bi及Pb的相对含量低于在空气中退火的薄膜。铁离子的价态波动是产生氧空位的原因,增加氧气有助于抑制氧空位的产生。虽然Pb的挥发会导致较差的微观结构,但其挥发并不会导致氧空位的产生。
A thin film of 0.7BiFeO_3-0.3PbTiO_3 (BFPT7030) was prepared on LaNiO_3 / SiO_2 / Si substrate by sol-gel method. The films were respectively annealed in air, oxygen, air and nitrogen by rapid annealing . Films annealed in air, oxygen flow and air flow all crystallized completely and showed a preferred (100) preferred orientation. The thin films annealed in a nitrogen stream were not tested for their hysteresis loops due to poor crystallinity. The BFPT7030 film annealed in air showed the largest remanent polarization and the smallest leakage current with a Pr of 30μC · cm -2 while the BFPT7030 film annealed in the air stream showed the smallest remanent polarization (Pr: 13μC · Cm ~ (-2)) and the maximum leakage current. The results of XPS showed that Fe 3+: Fe 2+ in BFPT7030 films annealed in air, oxygen and air were 2.09: 1, 1.65: 1 and 1.5: 1, respectively. While the relative content of Bi and Pb in BFPT7030 films annealed in oxygen flow and air flow was lower than those annealed in air. Variations in the valence of iron ions are responsible for oxygen vacancies. Increasing oxygen helps to suppress oxygen vacancies. Although the volatilization of Pb results in a poorer microstructure, its volatilization does not lead to the generation of oxygen vacancies.