铌酸钾钠(KNN)无铅压电薄膜凭借高居里温度,优良的压电性以及良好的生物相容性,可广泛地应用于驱动器、传感器及致动器等领域。本文采用溶胶凝胶法制备KNN薄膜,探究了热裂解温度和退火温度,离子(Li~+,Mn~(2+))掺杂及引入缓冲层(Nb_2O_5,SiTiO_3)对KNN薄膜结构和性能的影响。主要研究结果如下:热裂解温度过低,薄膜内有机物不完全分解,产生大量孔洞;热解温度过高导致碱金属离子挥发严重,薄膜氧空位增多。退火温度较低,晶粒不完全长大,薄膜结晶性差;退火温度过高,碱金属离子大量挥发。当热裂解温度为400℃,退火温度为600℃时,薄膜性能最优:在1k Hz下,ε_r为712,在200 kV/cm电场下,2P_r和2E_c分别为6.2μC/cm~2、118.6 kV/cm。Li离子主要取代KNN薄膜的A位离子,可以细化晶粒,改善薄膜的结晶性,使薄膜更加致密均匀。当Li离子掺杂量为1.5 mol%时,薄膜结晶性好,电学性能最优:在1 k Hz,ε_r为449.7,在200 kV/cm电场下,2P_r和2E_c分别为10.3μC/cm~2、107.2 kV/cm;Mn离子通过变价降低薄膜中载流子空穴浓度,...
【英文摘要】
Lead-free sodium potassium niobate(KNN)piezoelectric thin film has been regarded as one of the best choices to substitute for lead-based materials because of its high Curie temperature and excellent piezoelectric properties together with fine biocompatibility,which can be widely applied to drivers,sensors,actuators and other electronic devices.In this thesis,the KNN thin films were fabricated by sol-gel method successfully.The effects of thermal treatment temperatures,Li~+/Mn~(2+) doping and introducing buf...