Preparation And Properties Of Doped Bi₄Ti₃O₁₂ And Na_0.5Bi_0.5TiO₃ Ferroelectric Thin Films

In resent twenty or thirty years, people aim at developing ferroelectric memories. They have intensively studied ferroelectric thin films integrated with semiconductor. As the widely used ferroelectric materials, PbTiO3, Pb(Zr,Ti)O3, Pb(Mg,Nb)O3,etc. contain PbO from 60% to 70% by weight, which do heavy damage to our environment. Bi4Ti3O12 films show property degradation after being subjected to 107 read/write switching cycles.(Bi4-xAx)Ti3O12 film has been investigated extensively for its higher remnant polarization and fatigue-free characteristic. Recently, Na0.5Bi0.5TiO3 and K0.5Bi0.5TiO3 as lead-free materials have attracted considerable attention from the viewpoint of environmental protection.In this work, the preparation and properties investigation about Pr-substituted Bi4Ti3O12 thin films and Na0.5Bi0.5TiO3-K0.5Bi0.5TiO3 system were studied.We prepared four different proportion of Bi4Ti3O12, 0.15Pr-Bi4Ti3O12, (Na1-xKx)0.5Bi0.5TiO3 (x=0,0.2)thin films by the method of MOSD+ spin-coating. We studied the structure, surface morphologies and electric properties of the films by thermal analysis, infrared spectrum analysis, the x-ray diffraction analysis, atomic force microscopy (AFM), scanning electron microscopy (SEM), P-E hysteresis loops analysis, C-V loops analysis.