BiFeO_3薄膜的液相自组装制备与表征

利用自组装单层膜技术,以三氯十八烷基硅烷(OTS)为模板,以硝酸铋和硝酸铁为原料,柠檬酸为络合剂,在玻璃基片上制备了铁酸铋晶态薄膜.探讨了薄膜的煅烧温度和沉积温度对BiFeO3薄膜的影响.通过X射线衍射(XRD)、扫描电镜(SEM)及原子力显微镜(AFM)测试手段对BiFeO3薄膜的物相组成、显微结构和表面形貌进行了表征,EDS能谱测试为铁酸铋薄膜的化学组成提供了有力的证据.结果表明:利用自组装技术在600℃热处理后成功制备出了纯净的BiFeO3晶态薄膜,当沉积温度为70～80℃时铁酸铋薄膜结晶良好,样品表面均匀、致密.     

退火工艺对液相自组装法制备BiFeO3薄膜的影响

以Bi(NO3)3·5H2O,Fe(NO3)3·9H2O和柠檬酸为主要原料,采用液相自组装法,以OTS单分子层为模板,在ITO玻璃基片上成功制备了BiFeO3晶态薄膜.研究了退火温度以及保温时间对BiFeO3薄膜的影响.利用DSC/TG对铁酸铋前驱物结晶行为进行了表征,利用XRD和FE-SEM等测试手段对不同退火工艺下...     

微图案BiFeO_3薄膜的光刻自组装制备与表征(英文)

利用光刻自组装技术在玻璃基板上成功制备出图案化的BiFeO3薄膜.AFM和接触角测试表明,紫外光照射引起十八烷基三氯硅烷(OTS)单层膜改性,形成憎水的自组装单分子(SAM)区域和亲水的硅烷醇区域;XRD和XPS结果显示,OTS单层膜和紫外照射处理的玻璃基板表面诱导吸附的薄膜为纯相六方扭曲钙钛矿结构的BiFeO3薄膜;SEM和EDS表明,SAM区域沉积的BiFeO3薄膜不连续,在超声波震荡下容易脱落,而硅烷醇区域沉积的BiFeO3薄膜致密均一,与基底结合牢固,边缘轮廓清晰.     

pH值对液相自组装法制备纯相BiFeO3薄膜的影响

采用液相自组装法,Bi(NO3)3·5H2O,Fe(NO3)3· 9H2O为原料,柠稼酸为螯合剂,以OTS单分子层为模板,在ITO玻璃基片上成功制备了BiFeO3晶态薄膜.研究了前驱液pH值对BiFeO3薄膜的影响.利用XRD,EDS和SEM等测试手段对在不同pH值下沉积的BiFeO3薄膜进行了表征.结果表明,由于Bi...     

Fe3+/Bi3+对纯相BiFeO3薄膜的影响及生长机理研究

以Bi(NO3)3·5H2O,Fe(NO3)3·9H2O为原料,柠檬酸为螯合剂,用液相自组装法,在ITO玻璃基片上制备了纯相BiFeO3薄膜.研究了前驱液中Fe3+/Bi3+摩尔比对BiFeO3薄膜的影响.利用XRD,EDS,XPS,FE-SEM和FT-IR等测试手段对BiFeO3薄膜进行了表征.结果表明,由于柠檬酸对...     

Bi过量对BiFeO_3薄膜禁带宽度及光伏性能的影响

通过溶胶-凝胶法在掺氟的氧化锡(FTO)衬底上生长了前驱体溶液中Bi过量不同摩尔分数的铁酸铋(BiFeO3)多晶薄膜。利用X射线衍射仪(XRD),原子力显微镜(AFM),紫外-可见(UV-Vis)漫反射及光伏性能等测试手段进行表征,讨论了Bi过量对于BiFeO3薄膜晶粒尺寸、光学带隙及光伏性能的影响。结果表明:样品的晶粒尺寸随着Bi含量的增加先减小后增大。当Bi过量10%(摩尔分数,下同)时,BiFeO3薄膜的禁带宽度最小(Eg=2.31eV)。光伏性能研究表明,当Bi过量6%时,薄膜具有最大的开路电压值(Voc=0.31V)。     

自组装单层膜表面的Bi2Ti2O7薄膜制备与表征

以硝酸铋和钛酸四丁酯为原料,以三氯十八烷基硅烷(OTS)为模板,采用自组装单层膜(self-as-sembled monolayers,SAMs)技术,在玻璃基板上成功制备了Bi2Ti2O7晶态薄膜。借助X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)、X射线能谱(EDS)及原子力显微镜(AFM)等测试手段对Bi2Ti2O7薄膜进行了表征。结果表明,以OTS为模板利用自组装技术,经540℃煅烧2h可成功制得立方相Bi2Ti2O7晶态薄膜,且薄膜表面平整光滑,均匀致密。     

掺镧BiFeO3薄膜的制备及光伏特性研究

采用溶胶–凝胶法,用乙二醇甲醚作溶剂溶解Bi(NO3)3、Fe(NO3)3和La(NO3)3制备前体溶液,通过化学溶液沉积法在FTO导电玻璃基板上合成La3+掺杂的BiFeO3(BFO)薄膜,并研究了La3+掺杂对BiFeO3的能带及其光伏性能的影响。BiFeO3薄膜呈多晶钙钛矿结构,且随着La3+掺杂量的增加,BiFeO3的晶格常数依次递减。掺杂10%La3+的BiFeO3的能隙比未掺杂时稍有减小,为2.71 eV,随着La3+掺杂量的增加,BiFeO3的能隙增加到2.76 eV。采用改良法制备的La3+的掺杂量为10%的BiFeO3薄膜的最大开路电压为0.4 V,具有良好的光伏性能。     

钙钛矿铁酸铋微纳米粉体的水热合成

以BiCl3,FeCl3和KOH为原料,采用简便的水热法成功制备出不同形貌的铁酸铋粉体,通过XRD、SEM、FT-IR和TG—DSC对产物进行表征,结果表明,产物结晶为很好的三方相BiFeO3粉体,KOH加入量和表面活性剂对产物的形貌产生很大影响,红外图谱结果显示出BiFeO3的特征振动,TG—DSC结果获得BiFeO3产物的居里温度在830℃。     

二氧化铪晶态薄膜的自组装制备

利用自组装单层膜技术,在玻璃基板上生长有机硅烷单分子膜层,以Hf(SO4)2·4H2O和HCl配制HfO2前驱液,通过液相沉积在硅烷的功能性官能团上诱导生成二氧化铪薄膜.通过接触角测试仪、AFM、SEM及XRD等手段对膜材料的表面形貌和结构进行了研究分析.结果表明,利用自组装单层法成功制备出立方型的HfO2晶态薄膜,薄膜表面均一.     

Ferroelectric behavior in bismuth ferrite thin films of different thickness

The ferroelectric behavior of BiFeO(3) thin films is modified by changing the film thicknesses, where the BiFeO(3) thin films with different thicknesses were grown on SrRuO(3)/Pt/TiO(2)/SiO(2)/Si(100) substrates by radio frequency sputtering. The mixture of (110) and (111) orientations is induced for all BiFeO(3) thin films regardless of their thicknesses, together with the columnar structure and the dense microstructure. Their dielectric behavior is almost independent of the film thickness where all thin films have a low dielectric loss. A giant remanent polarization of 2P(r) ≈ 156.6-188.8 μC/cm(2) is induced for the BiFeO(3) thin films in the thickness range of 190-600 nm. As a result, it is an effective way to improve the ferroelectric behavior of the BiFeO(3) thin film by tailoring the film thickness.     

CSD法在亲水性的FTO基板上制备BiFeO3薄膜及其电性能的研究

利用化学溶液沉积法在亲水性的FTO基板上制备BiFeO3薄膜。利用XRD、FE-SEM、XPS、Agi-lent E4980A精密LCR仪及TF-Analyzer2000等分析手段对BiFeO3薄膜进行表征。结果表明,薄膜为纯相的结晶良好的多晶BiFeO3薄膜,由100～300nm的BiFeO3晶粒紧密的堆积而成,表面均匀平整。薄膜厚度为450nm。Fe的氧化态为Fe3+,并没有Fe2+出现。在10kHz时,介电常数和损耗分别为134和0.005。薄膜的剩余极化率为0.58μC/cm2,在0～250kV/cm的测试电场下漏导电流步伐保持在10-6 A/cm2以下。     

Adsorption-Controlled Growth of BiFeO3 by MBE and Integration with Wide Band Gap Semiconductors

BiFeO3 thin films have been deposited on (001) SrTiO3, (101) DyScO3, (011) DyScO3, (0001) AlGaN/GaN, and (0001) 6H-SiC single crystal substrates by reactive molecular beam epitaxy in an adsorption-controlled growth regime. This is achieved by supplying a bismuth over-pressure and utilizing the differential vapor pressures between bismuth oxides and BiFeO₃ to control stoichiometry in accordance with thermodynamic calculations. Four-circle x-ray diffraction and transmission electron microscopy reveal phase-pure, epitaxial films with rocking curve full width at half maximum values as narrow as 7.2 arc seconds (0.002°). Epitaxial growth of (0001)-oriented BiFeO3 thin films on (0001) GaN, including AlGaN HEMT structures, and (0001) SiC has been realized using intervening epitaxial (111) SrTiO₃ / (100) TiO₂ buffer layers. The epitaxial BiFeO3 thin films have 2 in-plane orientations: [1120] BiFeO>sub>3 || [1120] GaN (SiC) plus a twin variant related by a 180° in-plane rotation. This epitaxial integration of the ferroelectric with the highest known polarization, BiFeO3, with high bandgap semiconductors is an important step toward novel field-effect devices.     

Nanoscale control of exchange bias with BiFeO3 thin films

We demonstrate a direct correlation between the domain structure of multiferroic BiFeO3 thin films and exchange bias of Co 0.9Fe 0.1/BiFeO3 heterostructures. Two distinct types of interactions - an enhancement of the coercive field ( exchange enhancement) and an enhancement of the coercive field combined with large shifts of the hysteresis loop ( exchange bias) - have been observed in these heterostructures, which depend directly on the type and crystallography of the nanoscale ( approximately 2 nm) domain walls in the BiFeO3 film. We show that the magnitude of the exchange bias interaction scales with the length of 109 degrees ferroelectric domain walls in the BiFeO 3 thin films which have been probed via piezoresponse force microscopy and X-ray magnetic circular dichroism.     

Ce、V共掺杂BiFeO3多铁薄膜及其电性能研究

采用sol-gel法在Pt/Ti/SiO2/Si衬底上成功制备出纯BiFeO3(BFO)和Ce、V共掺杂Bi0.97 Ce0.03Fe1-x VxO3 (x=0,0.01,0.02,0.03)(BCFVx)薄膜.结构和形貌测试表明,Ce、V共掺杂使得BFO薄膜发生从菱方结构到伪四方结构的转变,且薄膜晶粒变小.介电性能和...     

不同退火方式对0.7BiFeO3-0.3PbTiO3薄膜的铁电性能及漏电流的影响

利用溶胶凝胶法在LaNiO3/SiO2/Si衬底上制备了0.7BiFeO3-0.3PbTiO3(BFPT7030)薄膜,研究了快速退火及常规退火两种不同的后续退火处理方式对薄膜铁电性能及漏电流性能的影响.XRD测试表明,经快速退火处理的BFPT7030薄膜结晶完好,呈现出单一的钙钛矿相.SEM测试结果显示,经快速退火处理的BFPT7030薄膜结晶充分,但经常规退火处理的BFPT7030薄膜表面致密性较好,且在升温速率为2℃/min时薄膜的晶粒更细小.经快速退火处理的BFPT7030薄膜的铁电性能较为优异,在升温速率为20℃/s时,其剩余极化Pr为22μC/cm2,矫顽场Ec为70 kV/cm,并具有较小的漏电流.XPS测试结果表明,经常规退火处理的BFPT7030薄膜其铁离子的价态波动较小.     

Fatigue-less relaxor ferroelectric thin films with high energy storage density via defect engineer

Thin film capacitors with excellent energy storage performances,thermal stability and fatigue endurance are strongly desired in modern electrical and electronic industry.Herein,we design and prepare lead-free 0.7Sr0.7Bi0.2TiO3-0.3BiFeO3-x％Mn(x=0,0.5,1.5,2,3)thin films via sol-gel method.Mn ions of divalent valence combine with oxygen vacancies,forming defect complex,which results in marked decline in leakage current and obvious enhancement in breakdown strength.A high energy storage density～47.6 J cm-3 and good efficiency～65.68％are simultaneously achieved in 2％Mn doped 0.7Sr0.7Bi0.2TiO3-0.3BiFeO3 thin film capacitor.Moreover,the 2％Mn-doped thin film exhibits excellent thermal stability in wide operating temperature range(35-115℃)and strong fatigue endurance behaviors after 108 cycles.The above results demonstrate that 2％Mn-doped 0.7Sr0.7Bi0.2TiO3-0.3BiFeO3 thin film capacitor with superior energy storage performances is a potential candidate for electrostatic energy storage.     

多铁性复合薄膜的结构及2-2 型双层复合磁电薄膜的制备方法

多铁性材料是一种新型材料,即一种材料同时具备铁电性、铁磁性和磁电耦和性。多铁性材料已成为当前国际上一个新的研究热点。介绍了多铁性复合薄膜的结构、2-2型多铁性复合薄膜的制备方法以及制备B iFeO3-Fe双层多铁性薄膜的最佳生长条件。     

Dielectric and electrical energy storage properties of BiFeO3–BaTiO3–SrTiO3 ternary bulk ceramics

Journal of Materials Science: Materials in Electronics - Recently, it is shown that the thin films of BiFeO3–BaTiO3–SrTiO3 have ultrahigh-energy storage density. However, the energy...     

Multiferroic BiFeO3 thin films for multifunctional devices

We report the metalorganic chemical vapor deposition of crystalline BiFeO3 films on platinized silicon substrates using n-butylferrocene, triphenylbismuth and oxygen. Based on thermogravimetric analysis data, the suitability of these two precursors for depositing BiFeO3 is discussed. The deposited films were characterized for structure and morphology using X-ray diffraction and scanning electron microscopy. Composition analysis using X-ray photoelectron spectroscopy revealed that the films were stoichiometric BiFeO3. Electrostatic force microscopy indicated that the film had polarizable domains that showed no deterioration in polarization over time long after electric poling. The film showed a saturation magnetization of 10 +/- 1 emu/cm3 at room temperature.