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Chinese Physics B 2012年第6期21卷 504-509页

作者：彭静吴传菊孙堂友赵文宁吴小锋刘文王双保揭泉林徐智谋 Department of Physics Wuhan University College of Sciences Wuhan University of Science and Technology Wuhan National Laboratory for Optoelectronics&College of Optoelectronic Science and Engineering Huazhong University of Science and Technology

BaTiO3 （BTO） ferroelectric thin films are prepared by the sol,el method. The fabrication and the optical properties of an InGaN/GaN multiple quantum well light emitting diode （LED） with amorphous BTO ferroelectric thin film are studied. The photolumineseence （PL） of the BTO ferroelectric film is attributed to the structure. The ferroeleetric film which annealed at 673 K for 8 h has the better PL property. The peak width is about 30 nm from 580 nm to 610 nm, towards the yellow region. The mixed electroluminescence （EL） spectrum of InGaN/GaN multiple quantum well LED with 150-nm thick amorphous BTO ferroelectric thin film displays the blue-white light. The Commission Internationale De L＇Eclairage （CIE） coordinate of EL is （0.2139, 0.1627）. EL wavelength and intensity depends on the composition, microstructure and thickness of the ferroelectric thin film. The transmittance of amorphous BTO thin film is about 93% at a wavelength of 450 nm-470 nm. This means the amorphous ferroelectrie thin films can output more blue-ray and emission lights. In addition, the amorphous ferroelectric thin films can be directly fabricated without a binder and used at higher temperatures （200 ℃-400 ℃）. It is very favourable to simplify the preparation process and reduce the heat dissipation requirements of an LED. This provides a new way to study LEDs.

关键词： InGaN/GaN multiple quantum well light emitting diodes ferroelectric film BaTiO3,optical properties

Photovoltaic and photoelectric response of Sn_(2)P_(2)S_(6) ferroelectric films

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Journal of Advanced Dielectrics 2019年第1期9卷 22-26页

作者： A.V.Solnyshkin I.L.Kislovay A.N.Belov V.I.Shevyakov D.A.Kiselev I.P.Raevski D.N.Sandjiev S.I.Raevskaya ational Research University of Electronic Technology Zelenograd Moscow 124498Russia Department of Condensed Matter Physics Tver State University Tver 170100Russia National University of Science and Technology“MISiS” Moscow 119049Russia Research Institute of Physics Southern Federal University Rostov-on-DonRussia

In the present work,the comparative study of the electric response of Sn_(2)P_(2)S_(6) films to the visible light action was carried out without and under external electric *** light flux modulated by a chopper induces the integral response comprising time-dependent photoelectric and photovoltaic *** was shown that spontaneous polarization influences the electric response characteristics.

关键词： Photovoltaic response photoelectric properties ferroelectric film

Effect of electromechanical the properties of epitaxial boundary conditions on ferroelectric thin films

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Chinese Physics B 2011年第10期20卷 407-412页

作者： Zhou Zhi-Dong Zhang Chun-Zu Jiang Quan Department of Materials Science and Engineering College of Materials Xiamen University Xiamen 361005 China Department of Civil Engineering School of Architecture and Civil Engineering Xiamen University Xiamen 361005 China College of Civil Engineering Nantong University Nantong 226019 China

The effects of internal stresses and depolarization fields on the properties of epitaxial ferroelectric perovskite thin films are discussed by employing the dynamic Ginzbur~Landau equation （DCLE）. The numerical solution for BaTiO3 film shows that internal stress and the depolarization field have the most effects on ferroelectric properties such as polarization, Curie temperature and susceptibility. With the increase of the thickness of the film, the polarization of epitaxia] ferroelectric thin film is enhanced rapidly under high internal compressively stress. With the thickness exceeding the critical thickness for dislocation formation, the polarization increases slowly and even weakens due to relaxed internal stresses and a weak electrical boundary condition. This indicates that the effects of mechanical and electrical boundary conditions both diminish for ferroelectric thick films. Consequently, our thermodynamic method is a full scale model that can predict the properties of ferroelectric perovskite films in a wide range of film thickness.

关键词： ferroelectric film internal stresses thermodynamic equations polarizations

Enhanced ferroelectric and improved leakage of BFO-based thin films through increasing entropy strategy

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2263-2273页

作者： Dongfei Lu Guoqiang Xi Hangren Li Jie Tu Xiuqiao Liu Xudong Liu Jianjun Tian Linxing Zhang Institute for Advanced Materials Technology University of Science and Technology BeijingBeijing 100083China

BiFeO_(3)(BFO)has received considerable attention as a lead-free ferroelectric film due to its large theoretical remnant ***,BFO suffers from a large leakage current,resulting in poor ferroelectric ***,the sol-gel method was used to deposit a series of BFO-based thin films on fluorine-doped tin oxide substrates,and the effects of the substitution of the elements Co,Cu,Mn(B-site)and Sm,Eu,La(A-site)on the crystal structure,ferroelectricity,and leakage current of the BFO-based thin films were *** confirmed that lattice distortion by X-ray diffraction can be attributed to the substitution of individual elements in the BFO-based *** and Eu substitutions contribute to the lattice distortion in a pseudo-cubic structure,while La is biased toward *** force microscopy confirmed that reversible switching of ferroelectric domains by nearly 180°can be realized through the prepared *** ferroelectric hysteresis loops showed that the order for the polarization contribution is as follows:Cu>Co>Mn(B-site),Sm>La>Eu(A-site).The current density voltage curves indicated that the order for leakage contribution is as follows:Mnfilm with a qualitative leap in the remnant polarization from 25.5(Bi_(0.985)Sm_(0.075)FeO_(3))to 98.8µC/cm^(2)(SmLa-CoCu)was prepared through the syner-gistic action of Sm,La,Co,and Cu *** leakage current is also drastically reduced from 160 to 8.4 mA/cm^(2)at a field strength of 150 kV/***,based on the increasing entropy strategy of chemical engineering,this st

关键词： increasing entropy synergistic ferroelectric film remnant polarization leakage current

MINIMUM SIZE OF 180 DEGREE DOMAINS IN ferroelectric THIN filmS COVERED BY ELECTRODES

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Applied Mathematics and Mechanics(English Edition) 2006年第8期27卷 1031-1036页

作者：陈永秋刘玉岚王彪 School of Mechanical and Power Engineering Harbin University of Science and TechnologyHarbin 150080 P. R. China School of Physics and Engineering Sun Yat-sen University Guangzhou 510275 P. R. China

ferroelectric domain switching under low voltage or short pulses is of interest for the development of high-density random access memory （FRAM） devices. Being necessarily very small in size, instability and back switching often occur when the external voltage is removed, which creates serious problems. In this investigation, a general approach to determine the minimum size of ferroelectric domain to avoid back switching was developed, and as an example, a 180° domain in a ferroelectric thin film covered by the upper and lower electrodes was considered in detail. We note that our approach is generally applicable to many other fields, including phase transformation, nucleation and expansion of dislocation loops in thin films, etc.

关键词： ferroelectric film 180° domain stability analysis back switching

Visualization of ferroelectric Domains in Thin films of Molecular Materials Using Confocal Micro-Raman Spectroscopy

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Chemical Research in Chinese Universities 2022年第6期38卷 1394-1399页

作者： ZHOU Wenqin FENG Zijie XIONG Yuan DU Guowei LIN Xiumei SU Qidong LOU Yuheng AN Shili YOU Yumeng Jiangsu Key Laboratory for Science and Applications of Molecular ferroelectrics Southeast UniversityNanjing211189P.R.China School of Chemistry and Chemical Engineering Southeast UniversityNanjing211189P.R.China

ferroelectrics are an important class of functional *** all their unique properties,the study of their ferroelectric domains and domain walls is of great interest due to their importance in ferroelectric *** are many methods to characterize ferroelectric domains,namely,scanning probe microscopy,optical microscopy,electron microscopy,***,newly emerged molecular ferroelectrics are attracting much attention from chemists,physicists and researchers in material sciences due to their structural flexibility,light mass,simple fabrication,***,for the characterization of molecular ferroelectric domains,most conventional methods require either a complicated preparation process or direct contact between physical probes and material surfaces,limiting the development of molecular ferroelectric *** this report,we have demonstrated that confocal micro-Raman spectroscopy,as a nondestructive and noncontact in-situ method,is very suitable for studying the ferroelectric polarization and structures of domains in molecular *** recently reported molecular ferroelectric trimethylchloromethyl ammonium trichlorocadmium(II)(TMCM-CdCl_(3))as an example,the non-180°domains have been characterized and visualized at different *** a simple and extendable method requires minimum sample preparation,which would further benefit the research of molecular ferroelectric domain engineering and promote the miniaturization and integration of molecular ferroelectric films.

关键词： Molecular ferroelectric ferroelectric film Domain Polarized Raman spectroscopy Raman imaging

Enhanced ferroelectric Properties of Predominantly (100)-oriented Ca_(0.4)Sr_(0.6)Bi_4Ti_4O_(15) Thin films on Pt/Ti/SiO_2/Si Substrates

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Journal of Materials Science & Technology 2010年第11期26卷 981-985页

作者： Suhue Fan Quande Che Fengqing Zhang Ran Yu Wei Hu College of Material Science and Engineering Shandong Jianzhu University Jinan 250101 China

Predominantly （100）-oriented Ca0.4Sr0.6Bi4Ti4O15 （C0.4S0.6BTi） thin films were prepared on Pt （111）/Ti/SiO2/Si substrates by a sol-gel method at annealing temperatures ranging from 650 to 850 ℃.The growth mode of the predominantly （100）-oriented C0.4S0.6 BTi thin films fabricated by the sequential layer annealing was discussed based on the structure evolution with the annealing *** remnant polarization and coercive field of the C0.4S0.6 BTi film annealed at 800 ℃ are 16.1 μC/cm 2 and 85 kV/cm,*** evident fatigue can be observed after 10 9 switching cycles.

关键词： Ca0.4Sr0.6Bi4Ti4O15 ferroelectric film Orientation

Orientation of Bi_(3.2)La_(0.8)Ti_3O_(12) ferroelectric Thin films with Different Annealing Schedules

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Journal of Wuhan University of Technology(Materials Science) 2009年第3期24卷 359-362页

作者：贺海燕 School of Materials Science and Engineering Shaanxi University of Science and Technology

Fatigue-free Bi3.2La0.8Ti3O12 ferroelectric thin films were successfully prepared on p-Si （100） substrates using metalorganic solution deposition process. The orientation and formation of 5-layers thin films were studied under different processing conditions using XRD. Experimental results indicate that increase in annealing time at 700 ℃ after preannealing for 10 min at 400 ℃ can remarkably increase （200）-orientation of the films derived from the precursor solutions with two contents of citric acid. Meanwhile, high content of citric acid increases the film thickness and is conducive to the α-orientation of the films with the preannealing, and low concentration of the solution is conducive to the c-orientation of the films without the preannealing.

关键词： Bi3.2La0.8Ti3O12 ferroelectric film technologic condition orientation

Multiferroic tunnel junctions

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Frontiers of physics 2012年第4期7卷 380-385页

作者： Yue-Wei Yin Muralikrishna Raju Wei-Jin Hu Xiao-Jun Weng Ke Zou Jun Zhu Xiao-Guang Li Zhi-Dong Zhang Qi Li Department of Physics Pennsylvania State University University Park PA 16802 USA Hefei National Laboratory for Physical Sciences at Microscale Department of Physics University of Science and Technology of China Hefei 230026 China Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Department of Materials Science and Engineering Materials Research Institute Pennsylvania State University University Park PA 16802 USA

Magnetic tunnel junctions with ferroelectric barriers, often referred to as multiferroic tunnel junc- tions, have been proposed recently to display new functionalities and new device concepts. One of the notable predictions is that the combination of two charge polarizing states and the parallel and antiparallel magnetic states could make it a four resistance state device. We have recently studied the ferroelectric tunneling using a scanning probe technique and multiferroic tunnel junctions using ferromagnetic Lao.7Cao.3MnO3 and ***.3MnO3 as the electrodes and ferroelectric （Ba, Sr）TiO3 as the barrier in trilayer planner junctions. We show that very thin （Ba, Sr）TiO3 films can sustain ferroelectricity up till room temperature. The multiferroic tunnel junctions show four resistance states as predicted and can operate at room temperatures.

关键词： multiferroic tunnel junction ferroelectric film tunneling magnetoresistance effect tun-neling electroresisitance effect magnetoelectric coupling

Coupling Enhancement of a Flexible BiFeO_(3) film-Based Nanogenerator for Simultaneously Scavenging Light and Vibration Energies

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Nano-Micro Letters 2022年第12期14卷 137-150页

作者： Xiao Han Yun Ji Li Wu Yanlong Xia Chris RBowen Ya Yang CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-Nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 101400People’s Republic of China Department of Mechanical Engineering University of BathBath BA27AKUK School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing 100049People’s Republic of China Center On Nanoenergy Research School of Physical Science and TechnologyGuangxi UniversityNanning 530004People’s Republic of China

Coupled nanogenerators have been a research hotspot due to their ability to harvest a variety of forms of energy such as light,mechanical and thermal energy and achieve a stable direct current *** films are frequently investigated for photovoltaic applications due to their unique photovoltaic properties and bandgap-independent photovoltage,while the flexoelectric effect is an electromechanical property commonly found in solid ***,we effectively construct a new form of coupled nanogenerator based on a flexible BiFeO_(3) ferroelectric film that combines both flexoelectric and photovoltaic effects to successfully harvest both light and vibration *** device converts an alternating current into a direct current and achieves a 6.2% charge enhancement and a 19.3%energy enhancement to achieve a multi-dimensional"1+1>2"coupling enhancement in terms of current,charge and *** work proposes a new approach to the coupling of multiple energy harvesting mechanisms in ferroelectric nanogenerators and provides a new strategy to enhance the transduction efficiency of flexible functional devices.

关键词： ferroelectric film Coupled nanogenerators Photovoltaic effect Flexoelectric effect Energy collection