SrTiO3(111)衬底上KTa0.65Nb0.35O3薄膜的取向生长研究

以乙酸钾、乙醇钽、乙醇铌为前驱体，在SrTiO_3（111）衬底上取向生长了KTa_（0.65）Nb_（0.35）O_3薄膜.通过DTA-TG分析，确定了预烧工艺，发现钙钛矿结构KTN在高温（＞950℃）下可分解，产生缺钾中间相K_2Ta_4O_11．单层凝胶膜预热处理（＞450℃），多层覆盖，慢速升降温（1～2℃／min），750℃保温2h，可得到晶粒大小分布均匀，平均直径约0．2μm、致密的薄膜．升高温度、延长时间，晶粒长大，甚至团聚，产生气孔、裂纹，烧结温度应控制在950℃以下．     

BST薄膜的研究现状与发展趋势

综述了(Ba1-xSrx)TiO3(BST)薄膜材料的研究现状，包括薄膜的制备技术、电极材料的选择、组分与掺杂对电学及介电性能的影响，分析了与薄膜相关的缺陷和可靠性现象，并对未来可能的进展作了简单的描述。     

Preparation and dielectric properties of compositionally graded （Ba, Sr）TiO3 thin film by sol-gel technique

Compositional graded BaxSr1-xTiO3 （x=0.6, 0.7, 0.8, 0.9, 1.0） （BST） thin films （less than 400 nm） were fabricated on Si and Pt/Ti/SiO2/Si substrates by sol-gel technique. A special heating treatment was employed to form the uniform composition gradients at 700 ℃. The microstructures of the films were studied by means of X-ray diffraction, atomic force microscope and field emission scanning electron microscopy. The results show that the films have uniform and crack-free surface morphology with perovskite structure phase. The small signal dielectric constant （εr） and dielectric loss （tanδ） are found to be 335 and 0.045 at room temperature and 200 kHz. The dielectric properties change significantly with applied dc bias, and the graded thin film show high tunability of 42.3% at an applied field of 250 kV/cm. All the results indicate that the graded BST thin films prepared by sol-gel technique have a promising candidate for microelectronic device.     

Effects of B2O3-SiO2 doping on electrical properties of Ba0. 65 Sr0. 35 TiO3 ceramics

Ba0. 65 Sr0. 35 TiOa ceramics doped with B2O3-SiO2 glass composition were prepared by using conventional solid-state reaction method. The effects of glass dopant on the dielectric and ferroelectric properties were investigated. The results show that the dielectric constant decreases while the dielectric loss increases after doping. And as the glass content increases the dielectric constant decreases while the dielectric loss changes slightly. From the complex impedance analysis the resistance and the relaxation time of the grain and the grain boundary can be calculated.Comparing the P--E hysteresis loop of undoped Ba0.65 Sr0.35 TiO3 ceramics with that of B2O3-SiO2 doped Ba0.65 Sr0.35 TiO3 ceramics, it can be seen that the remanent polarization decreases when the B2O3-SiO2 content is lower than 8% (molar fraction), and the coercive field increases with the increase of B2O3-SiO2 content.     

低压ZnO压敏陶瓷晶粒边界电子陷阱态的研究

应用４１９２Ａ低频阻抗分析仪测量了低压ＺｎＯ压敏陶瓷的复电容曲线,研究了烧结温度对复电容曲线压低角的影响规律,探讨了晶粒边界耗尽层中电子陷阱的种类和起因并对电子陷阱的特征参数进行了表征．实验发现：在低压ＺｎＯ压敏陶瓷中存在两种非理想的Ｄｅｂｙｅ弛豫现象,对于每一种弛豫,其复电容曲线存在压低现象,且其压低角随着烧结温度的升高而迅速减小．在低压ＺｎＯ压敏陶瓷的耗尽层区域内存在两种电子陷阱,它们分别位于导带底０．２０９和０．３４２ｅＶ处,其中０．２０９ｅＶ处的陷阱能级对应于本征施主Ｚｎ×ｉ的二次电离,而０．３４２ｅＶ处的陷阱能级对应于氧空位ＶＯ的一次电离．     

Enhanced photovoltaic performance in TiO2/P3HT hybrid solar cell by interface modification

A TiO2/P3HT hybrid solar cell was fabricated by infiltrating P3HT into the pores of TiO2 nanorod arrays. To further enhance the photovoltaic performance, anthracene-9-carboxylic acid was employed to modify the interface of TiO2/P3 HT before P3HT was coated. Results revealed that the interface treatment significantly enhances the photovoltaic performance of the cell. The efficiency of the hybrid solar cells reaches 0.28% after interface modification, which is three times higher compared with the un-modified one. We find that except for the increased exciton dissociation efficiency recognized by the previous reports, the suppressing of electron back recombination is another important factor leading to the enhanced photovoltaic performance.     

Ba0.64Sr0.36TiO3薄膜的介电与热释电性能的研究

应用溶胶-凝胶工艺在Pt/SiO2/Si(100)衬底上制备了Ba0.64Sr0.36TiO3薄膜,研究了薄膜的结构与电学性能.实验结果表明Ba0.64*Sr0.36TiO 3薄膜经700 ℃热处理1h,薄膜呈现出钙钛矿结构.当测试频率为200 Hz 时, 薄膜的介电常数和损耗因子分别为592和0.028.在40 ℃时,Ba0.64Sr0.36TiO 3薄膜存在一扩散铁电-顺电相变.在室温(25 ℃)、100 kHz条件下测试薄膜的C-V 特性得到一"蝶形"曲线,表明Ba0.64Sr0.36TiO3薄膜在室温下处于铁电相, 且当直流偏压从-5 V增至+5 V期间, 薄膜电容由495 pF增至1 108pF.热释电性能测试结果表明室温下Ba0.64Sr0.36TiO3薄膜的热释电系数为1 860μC/(m2*K), 材料的优值为37.4 μC/(m3*K), 这些结果表明应用溶胶-凝胶工艺制备的Ba0.64Sr0.36TiO3薄膜完全能满足红外探测器和热成像应用的需要.     

ZrO2基陶瓷超微粉的热分解及晶化过程研究

以Ｚｒ（ＯＣ３Ｈ７）４和Ｙ（ＣＨ３ＣＯＯ）３为原料，应用溶胶－凝胶法制备了ＺｒＯ２＋９％摩尔分数Ｙ２Ｏ３超微粉末。通过ＴＧ－ＤＴＡ，ＸＲＤ分析技术，研究了粉末的热分解过程及晶化过程，结果表明：ＺｒＯ２＋９％Ｙ２Ｏ３超微粉末的热分解过程分为三个阶段；水份和有机溶剂的蒸发；有机基团的燃烧和无定形ＺｒＯ２的形成，无定形ＺｒＯ２向立方相ＺｒＯ２的转变，钇稳定立方相ＺｒＯ２的合成温度在４７０℃左右。     

溶胶－凝胶工艺合成ZrO_2超微粉末的研究

以自制Ｚｒ（ＯＣ_３Ｈ_７）_４和Ｙ（ＣＨ_３ＣＯＯ）_３为原料，应用溶胶、凝胶法制备了组份为ＺｒＯ_２－９ｍｏｌ％Ｙ_２Ｏ_３超微粉末．实验表明：温度、湿度、溶液的浓度．介质和催化剂等是影响形成溶胶、凝胶的主要因素．通过ＴＧ－ＤＴＡ、ＸＲＤ、ＢＥＴ比表面积测量以及ＴＥＭ等分析手段研究了粉末的结构与性能．结果表明：钇稳定立方相二氧化锆（ＹＳＺ）超微粉末的合成温度在４７０℃左右．粉末经５００℃以上热处理后变为纯立方相结构．５００℃煅烧２ｈ后的超微粉末颗粒呈球形或近似球形，比表面积为６４．０４ｍ￣２／ｇ，粒径为１５．７ｎｍ．随着烧结温度的升高，ＹＳＺ超微粉末的比表面积减小，粒径增大，预示着颗粒间发生团聚，一次颗粒间的团聚引起了表面积的明显损失和界面的形成．     

金属氧化物气敏传感器的研究现状及其发展趋势

综述了国内外金属氧化物气敏传感器的生产和应用概况，分析了国内外目前的生产技术水平与现状，展望了金属氧化物气噩在的发展前景。