La,V共掺杂的Bi_4Ti_3O_(12)铁电薄膜的溶胶-凝胶法制备及性能测试

采用溶胶-凝胶(sol-gel)工艺在Pt/TiO2/SiO2/p-Si(100)衬底上制备出Bi4Ti3O12(BIT)和Bi3.25La0.75Ti2.97V0.03O12(BLTV)铁电薄膜,研究了La,V共掺杂对BIT薄膜的晶体结构和电学性能的影响.BIT薄膜为c轴择优取向,BLTV薄膜为随机取向,拉曼光谱分析表明V掺杂降低了TiO6(或VO6)八面体的对称性,也增强了Ti—O键(或V—O键)杂化.BLTV薄膜的剩余极化Pr为25.4μC/cm2,远大于BIT薄膜的9.2μC/cm2,表现出良好的铁电性能.疲劳、漏电流测试显示BLTV薄膜具有优良的抗疲劳特性和漏电流特性,表明La,V共掺杂能有效地降低薄膜中的氧空位.

Properties of La and V codoped Bi_4Ti_3O_(12) thin film prepared by sol-gel method

Bi_4Ti_3O_(12) (BIT) and Bi_(3.25)La_(0.75) Ti_(2.97) V_(0.03)O_(12) (BLTV) thin films were fabricated on the Pt/TiO_2/SiO_2/p-Si (100) substrate using sol-gel method. The effect of La and V codoping on the structural and electrical properties of BIT thin films was investigated. BIT thin film exhibits predominantly c-axis orientation while BLTV thin film shows random orientation. Raman spectroscopy shows that TiO_6 (or VO_6) symmetry decreases and Ti-O (or V-O) hybridization increases with V substitution. The residual polarization of BLTV thin film is 25.4 μC/cm~2, which is larger than that of BIT thin film (9.2 μC/cm~2). BLTV thin film also shows excellent fatigue endurance and low leakage current characteristics, which implies the oxygen vacancies are suppressed by La and V codoping in the thin films.