Surface structure of silver thin films on In2O3:Sn and Al2O 3 †

Surface structure of thin silver films (200 Å) on two technologically important films, indium tin oxide (ITO) and aluminium oxide, has been studied using scanning tunneling microscope. ITO films were prepared by reactive electron beam evaporation. Aluminium oxide films were prepared by oxidizing 2000 Å thick aluminium films evaporated on to H₂ terminated single crystal silicon substrates. The surface structure of silver on ITO and aluminium oxide appeared to be same and was characteristic of Stranski-Krastanov type. The observed asymmetry in the island shape was attributed to the anisotropic nature of the strain fields surrounding the nucleation centres.     

YBa2Cu3O x superconducting thin films prepared by low temperature vacuum codeposition

Y-Ba-Cu-O films were prepared by low temperature codeposition of three components. The Y and Cu contents were evaporated from metallic sources, while Ba was vacuum-evaporated from Ba, BaO and BaF₂ sources in separate codeposition experiments. The lowest temperature at which superconducting YBa₂Cu₃O _x thin films (about 0.5μm thick) preparedin situ was near 500°C. This process enables preparation of superconducting films on various substrates (SrTiO₃, MgO, Al₂O₃, Si) without a buffer layer. Zero-resistance critical temperature was as high as 88 K and the critical current density was 10⁴ A/cm² at 4.2 K. The morphology of the films was granular with disordered grain orientation, the average grain size being typically 0.5μm.     

近红外区高透射率In2O3:W透明导电氧化物薄膜的研究

采用反应直流磁控溅射法制备了掺钨氧化铟(In2O3W,IWO)透明导电氧化物薄膜.薄膜中掺杂的钨离子与被替代的铟离子之间存在高价态差.与相同电阻率的ITO(In2O3Sn)相比,IWO薄膜具有载流子浓度低、迁移率高和近红外区透射率高的特点.研究了氧分压、溅射电流等参数对IWO薄膜电学和光学性能的影响.制备的多晶IWO薄膜最佳电阻率为3.1×10-4 Ω·cm,最高载流子迁移率为58 cm2 V-1s-1,可见光范围平均透射率大于90%,近红外区(700～2500 nm)平均透射率约为85%.     

Decompression‐Driven Superconductivity Enhancement in In2Se3

An unexpected superconductivity enhancement is reported in decompressed In₂Se₃. The onset of superconductivity in In₂Se₃ occurs at 41.3 GPa with a critical temperature (T_c) of 3.7 K, peaking at 47.1 GPa. The striking observation shows that this layered chalcogenide remains superconducting in decompression down to 10.7 GPa. More surprisingly, the highest T_c that occurs at lower decompression pressures is 8.2 K, a twofold increase in the same crystal structure as in compression. It is found that the evolution of T_c is driven by the pressure‐induced R‐3m to I‐43d structural transition and significant softening of phonons and gentle variation of carrier concentration combined in the pressure quench. The novel decompression‐induced superconductivity enhancement implies that it is possible to maintain pressure‐induced superconductivity at lower or even ambient pressures with better superconducting performance.     

Preparationin situ and properties of thin films HTSC YBa2Cu3O x

We describe the technique ofin situ preparation of thin (d=0, 1-1μm) YBCO films by the RF magnetron sputtering of the ceramic target in the argon-oxygen atmosphere on the heated substrates, and report the preliminary results of investigation of the multilayer structure based on such films.     

Ba0.5Sr0.5 TiO3薄膜、Ba0.1Sr0.9 TiO3/YBa2 Cu3O7-δ异质薄膜的制备及介电性能研究

铁电钛酸锶钡(BSTO)薄膜具备十分优越的铁电/介电性能,在可调谐微波器件和动态随机存储器(DRAM)方面显示出十分诱人的应用前景.而YBa2Cu3O-δ(YBCO)高温超导薄膜作为其电极引入,明显降低了微波损耗,能够大大优化器件的性能.本文针对微波器件性能要求对比了各种常用基片的性能参数,描述了目前BSTO薄膜与BSTO/YBCO异质薄膜制备中存在的问题以及薄膜介电性能测试表征方法.利用脉冲激光沉积(PLD)技术成功制备出结构完整和质量较高的Ba0.5Sr0.5TiO3薄膜.同时,在1.2°斜切LaAlO3基片上研制有Ba0.1Sr0.9TiO3/YBa2Cu3O7-δ异质双层膜,在1MHz频率、77K温度条件下,其介电常数为1200,介电损耗为0.0045,±30V直流偏压时可调性达到60%,在液氮温度下表现出良好的应用前景.     

Fe3O4缓冲层对CoFe2O4薄膜磁性能的影响

采用射频磁控溅射在基片Si（100）和Fe3O4（20nm）/Si（100）上制备了钴铁氧体（CoFe2O4）薄膜，制备的薄膜在空气气氛中进行300～1000℃的退火处理，采用XRD、VSM分析了薄膜的微结构以及磁性能。结果表明，制备的钴铁氧体薄膜均具有尖晶石结构，Fe3O4缓冲层薄膜促进了钴铁氧体薄膜的结晶，但降低了钴铁氧体薄膜的垂直各向异性和垂直于膜面方向的矫顽力，而钴铁氧体薄膜的磁化强度和矩形度得到了一定的提高。     

Reactive deposition of Y1Ba2Cu3O7 −x superconductor films by pulsed laser ablation from an unreacted mixture of Y2O3, BaCO3 and CuO

Superconducting thin films of Y₁Ba₂Cu₃ O_{7 −x} have been deposited on (100) Y-ZrO₂ substrates by pulsed excimer laser ablation from anunreacted mixture of Y₂O₃, BaCO₃ and CuO. The films deposited at substrate temperature of 680°C and oxygen partial pressure of 200 mtorr were found to be superconducting with zero resistive transition temperature of 89 K and critical current density of over 3 × 10⁵ A/cm² at 77 K. These results are compared with those obtained by laser ablation from a sintered superconducting pellet.     

MgAl2O4透明陶瓷中电子辐照诱导缺陷退火行为研究

用能量为1.7MeV,束流强度0.7μA*cm-2,总注量6.3×l016 cm-2的电子辐照镁铝尖晶石透明陶瓷,并对辐照后的样品进行等时退火,利用UV-VIS和PAT测试,表明通过电子辐照样品在237nm和370nm处产生吸收带,它们主要是F心及V型色心.通过退火可以使F心及V型色心吸收峰消除,但F心的消除温度要高于V型色心,且其在退火过程中形成F聚心,F聚心随F心聚集增加其峰位将向紫外移动.     

退火温度对透明导电Ga_2O_3/ITO周期多层膜性能的影响

用射频磁控溅射Ga2O3陶瓷靶材和直流磁控溅射ITO靶材在石英玻璃衬底制备Ga2O3/ITO周期多层膜。样品在300~800℃真空退火1小时,研究退火温度对薄膜光学和电学性能的影响。400℃退火的Ga2O3/ITO周期多层膜面电阻和电阻率低至68.76Ω/□和3.47×10-3Ω·cm,载流子浓度和霍尔迁移率高达1.30×1020cm-3和14.02cm2 V-1s-1。退火温度超过500℃后,Ga2O3膜层和ITO膜层之间开始相互扩散,薄膜结晶质量和导电性变差。所有退火薄膜在紫外-可见光范围的平均光学透过率高于83%,光学带边吸收随退火温度增加发生蓝移,光学带隙从4.59eV增加到4.78eV。     

In2O3薄膜及纳米颗粒制备进展

主要介绍了In2O2薄膜及其纳米颗粒的制备方法和特点,并比较了它们的优缺点。     

Superconductivity behaviour of screen-printed LnBa2Cu3O7 (Ln=Eu,Y) films

Thick films of the highT _csuperconducting oxides, LnBa₂Cu₃O₇, Ln = Eu, Y, have been fabricated by screen printing on alumina and SrTiO₃ substrates. Conditions for optimum superconductivity behaviour of the films have been established.T _c ^onset varies from 90–94 K for all the films but zero resistance was observed only in a few cases.     

以Al2L3／AlN为复合绝缘缓冲层的ZnO—TTFT透过率的研究

采用射频反应磁控溅射的方法，以ITO（铟锡氧化物）玻璃为衬底，在Al2O3／AN复合栅极绝缘层上沉积有源层ZnO薄膜，并以Al作为透明薄膜晶体管器件源极和漏极，通过XRD、透射光谱研究了透明薄膜晶体管的有源层ZnO的结晶情况以及对器件在可见光范围内的透过特性的影响，得出以Al2O3／AlN为复合缓冲层薄膜晶体管，在400℃温度下退火处理后，ZnO有源层有较好的c-axis（002）择优取向，器件在可见光的范围内整体透过率在88%以上，从而实现了ZnO-TFT器件在可见光范围内的透明。     

掺杂浓度对Al2O3:Ce3+薄膜发光性能的影响

应用中频反应磁控溅射技术在载玻片上制备掺铈的Al2O3薄膜,在固定的电源功率下,氩气流量为43ml/min,氧流量为10ml/min,室温下溅射时间为90min的条件下,通过控制薄膜中的Ce3 离子的掺杂量来改变薄膜的发光性能.通过X光能量散射谱(EDS)和光致发光测量,得到发光强度和发光峰位对薄膜中的Ce3 浓度有强烈的依赖关系,并且分析了产生这种关系的原因;对发光激发谱分析表明,薄膜发光是源于薄膜中形成的氯化铈集合体中的Ce3 .Al2O3:Ce3 发光膜可应用于需要蓝光发射的平板显示领域.     

Fe和Fe3O4硫化制备的FeS2薄膜的性能

用溅射Fe和电沉积Fe3O4先驱体硫化制备出FeS2薄膜,研究了不同先驱体对硫化过程和FeS2薄膜性能的影响．结果表明,两种先驱体结晶成的FeS2能够在一定程度上保留先驱体形貌特征．Fe生成FeS2的热力学驱动力比较高,虽然可能生成FeS的过渡相;Fe硫化生成的薄膜平整致密,晶粒生长比较充分,尺寸较大,其禁带宽度接近理论值．Fe3O4硫化生成FeS2的热力学驱动力较低,生成的薄膜表面疏松多孔,晶粒细小;薄膜的晶界等面缺陷比例较大和几何连续性较低使其电阻率较高、禁带宽度和载流子迁移率低于Fe膜硫化FeS2薄膜．     

纳米La2O3／TiO2复合薄膜的制备及光催化性能研究

采用溶胶-凝胶法在陶瓷基体上制备了纳米La2O3／TiO2复合薄膜。利用XRD研究了La2O3不同复合量对纳米TiO2晶型转化的影响，利用SEM研究了Al2O3底膜对La2O3／TiO2复合薄膜形貌的影响，利用亚甲基兰溶液紫外光降解实验研究了La2O3／TiO2复合薄膜的光催化性能．结果表明：复合0．5％（物质的量）La2O3的TiO2干凝胶经850℃煅烧后仍为锐钛矿（64％（质量分数））占主导的混晶结构，平均粒径在10nm左右；当Al2O3底膜和La2O3／TiO2复合薄膜的厚度分别为4层和3层时，经850℃煅烧后，复合薄膜致密且无微裂纹出现，而且具有佳的光催化性能．     

High-rate reactive deposition of transparent SiO2 films containing low amount of Zr from molten magnetron target

The paper reports on a reactive deposition of transparent SiO₂ films with a low amount (≤ 3 at.%) of Zr prepared from the molten target using the AC pulsed dual magnetron. It is shown that the deposition rate a_D of the transparent oxide film strongly increases at the critical target power density (W_t)_cr when the solid target starts to melt and the magnetron operates with a molten target. In this case, the evaporation of target material plays a dominant role in the reactive deposition of thin films. This process is called the ionized magnetron evaporation. Oxide films reactively deposited from the molten target are well transparent and highly elastic. The maximum deposition rate of the transparent oxide film achieved in our experiments is 814 nm/min.     

Preparation and characterization of indium oxide (In2O3) films by activated reactive evaporation

The electrical and optical properties of In₂O₃ films prepared at room temperature by activated reactive evaporation have been studied. Hall effect measurements at room temperature show that the films have a relatively high mobility 15 cm²v⁻¹s⁻¹, high carrier concentration 2·97 × 10²⁰/cm³, with a low resistivityρ = 1·35 × 10⁻³ ohm cm. As-prepared film is polycrystalline. It shows both direct and indirect allowed transitions with band gaps of 3·52eV and 2·94eV respectively.     

溶胶-凝胶法制备0.1BiFeO3-0.9SrBi2Nb2O9铁电薄膜的结构和光学性质研究

采用硝酸铋[Bi(NO3)3·5H2O]、硝酸锶[Sr(NO3)2]、硝酸铁[Fe(NO3)3·9H2O]和乙醇铌[Nb(OC2H5)5]作为起始原料,乙二醇甲醚[C3H8O2]作为溶剂配制掺Fe的SrBi2Nb2O9前驱体溶液,利用溶胶-凝胶法在石英衬底上制备出0.1BiFeO3-0.9SrBi2Nb2O9铁电薄膜.研究了该薄膜的表面形貌、组分、晶体结构和光学性质.结果表明,经400℃退火后薄膜为非晶结构,而在空气中经600℃退火1h后,沉积的薄膜晶化成钙钛矿结构.制备的薄膜表面平整,颗粒分布均匀,表现出良好的光透过性,该薄膜的光学能隙大约为2.5eV.     

H2C2O4稳定剂对SOl-Gel法制备LiNbO3薄膜的影响

研究了分别以H2C2O，HNO3，HCOOH和CH3COOH作稳定剂的LiNbO3薄膜先驱液的稳定性，发现H2C2O4作稳定剂的先驱液的稳定性最好，用sol-gel法在Si(110)基板上制备了以H2C2O4作稳定剂的LiNbO3薄膜，并对LiNbO3薄膜进行了IR，XRD和SEM表征，结果表明，生成的LiNbO3为多晶，与HNO3相比，以H2C2O4作稳定剂制备的LiNbO3薄膜形貌较差。