Preparation, Characterization And Device Properties Of Barium Titanate-based Thin Films

Perovskite oxides exhibit abundant structural phases,which carry different physical phenomena,and thus produce a variety of technical applications.Among many perovskite oxides,barium titanate-based materials have been extensively studied in ferroelectric thin film devices due to their high dielectric constant,low dielectric loss and good ferroelectric properties.They exhibit a photovoltaic effect under near ultraviolet radiation,which makes them suitable for various applications,such as multilayer ceramic capacitors,thermistors,piezoelectric devices,electro-optical modulators,dynamic random access memory,solar cells,ultraviolet photodetection device.As we all know,doping is an effective method to change the electrical properties of thin films.In the ABO₃type such as barium titanate perovskite,the replacement of B-site cations with appropriate acceptors,donors or equivalent impurity ions will change the electrical properties of these materials.The rise of barium titanate-based thin film materials provides new ideas for exploring the mechanism of magnetoelectric and ferroelectric photovoltaics and improving their power conversion efficiency,and has become one of the current hot spots in the field of condensed matter physics.In the thin film preparation process,the sol-gel process is suitable for the synthesis of thin films and the mixing of starting materials at the atomic level due to its simple preparation conditions,low process cost,and resulting product homogeneity,high phase purity and relatively low the manufacturing temperature and other advantages have attracted much attention.Therefore,in this paper,sol-gel combined with rapid thermal processing technology is used to successfully prepare barium titanate（BaTiO₃,BTO）transition metal element Mn,Zr doped series films based on its structure,morphology,electrical and optical performance was characterized in detail.And the more excellent Mn doped barium titanate(BaTi_0.9Mn_0.1O₃,BTMO)was selected from it,used as the ferroelectric phase to compound with bismuth ferrite（BiFeO₃,BFO）to obtain 2-2 type BaTi_0.9Mn_0.1O₃/BiFeO₃（BTMO/BFO）composite structure film,and its performance has been systematically characterized.It is found that the magnetic parameters of the BTMO/BFO heterostructure film（2M_r=3.84 emu/cc）have been significantly increased,and compared with the BTO film,it has better ferroelectric properties.In addition,it has a strong absorption band below 450 nm,that is,it can absorb a certain amount of visible light,and has a lower optical band gap（E_g=2.36 e V）,so as to obtain a better ferroelectric PV response,and obtain a 0.25 V open circuit voltage and 18.15μA/cm²short circuit current.It shows that the use of BTMO/BFO composite structure film in photovoltaic devices has certain value and application prospects,and it also provides a way of thinking for studying the mechanism of ferroelectric photovoltaics.