Si(100)衬底上CeO2薄膜的脉冲激光制备及性能研究

用CeO2陶瓷靶材,使用脉冲激光沉积(PLD)技术在Si(100)衬底上制备了CeO2薄膜.研究了衬底温度、沉积氧压对薄膜性能的影响,实验制备出了高度(111)取向的CeO2薄膜.使用X射线衍射(XRD)、反射式高能电子衍射(RHEED)对薄膜进行晶体结构的表征.结果表明:随着衬底温度的增加,薄膜中的残余宏观应力(拉应力)及微观应力逐渐减小,薄膜结晶质量不断提高,而沉积氧压对此影响较小.RHEED图像显示使用PLD方法在Si衬底上沉积的薄膜具备较高的结晶性及原子级平整的表面.使用原子力显微镜(AFM)对样品进行表面粗糙度分析,发现不同温度下生长的薄膜均具有光滑的表面,方均根粗糙度(RMS)均在0.4 nm以下.使用Keithley 4200半导体测试仪、椭偏仪对薄膜进行电性能及光学性能分析,发现衬底温度对薄膜的电学性能有显著影响,并且CeO2薄膜结晶状态与电学性能有直接的联系.     

脉冲激光沉积ZnO薄膜的表面研究

脉冲激光沉积技术（PLD）目前已成为一种重要的制备氧化锌（ZnO）薄膜的技术,但是由于脉冲瞬间沉积时不能避免产生液滴及形成大小不一的颗粒,因此在制备高质量ZnO薄膜的表面均匀性方面还存在一定弊端。文章采用PLD（KrF准分子激光器：波长248 nm,频率5 Hz,脉冲宽度20 ns）方法在衬底温度450℃和氧气流量10 sccm下以高纯ZnO为靶材、在单晶硅衬底表面沉积120 min成功生长了ZnO薄膜。扫描电子图像（SEM）显示ZnO薄膜表面有明显凸起的颗粒,文章通过俄歇能谱仪对ZnO薄膜进行了研究,分析了ZnO薄膜的表面成分及凸起颗粒微观区域的成分。实验结果表明制备的ZnO薄膜表面明显突起的颗粒为ZnO颗粒,文章为PLD法制备ZnO薄膜易形成大小不一的颗粒提供了理论依据。     

Room temperature ferromagnetism and magnetoelectric coupling in (K0.5Na0.5)NbO3 PLD nanocrystalline films

(K_0.5Na_0.5)NbO₃ nanocrystalline films have been successfully prepared on conductive Si substrate under different conditions by pulsed laser deposition. Room temperature ferromagnetism has been achieved through the introduction of cation (K, Na) vacancies during deposition at the expense of the deterioration of ferroelectricity. In addition to positive magnetocapacitance effect and electrical manipulation of magnetization, the new phenomenon that the orthometric application of an electric field and magnetic field on the surface of film leads to an enormous enhancement of in-plane saturation magnetization has been first observed, indicative of a strong magnetoelectric coupling which has a memory effect on the saturation magnetization at room temperature.     

Deposition of large-area graded (Pb1−xLax)TiO3 thin films by pulsed laser depesition

Abstract

Thin films of the composition (Pb_1?xLa_x)TiO₃, PLT, with x=0.05, 0.10 and 0.15 were sequentially pulsed laser deposited on Pt(Si) substrates at 200°C, followed by post-annealing at 550–600°C in furnace to result in a film with graded composition. The ferroelectric properties of the graded materials are markedly different from those of the uniform thin PLT films. For down graded materials, which contain PLT5 composition (x=0.05) at the top and PLT 15 composition (x=0.15) at the bottom of the films, the hysteresis loops are slim and the width of the P-E curves increases with voltage cycling, attaining an equilibrium polarization states similar to the P-E properties of PLT 15 thin films. By contrast, the ferroelectric hysteresis properties reaches the same value as those of PLT5 thin films when the composition is up-graded.     

原子氧处理对氧化锌薄膜的结构及光学特性的影响

本文采用脉冲激光沉积方法在Al2O3(0001)基底上,500℃的衬底温度条件下,制备出了具有高度C轴择优取向的氧化锌薄膜.用自行研制的同轴源型原子氧地面模拟装置,以1.62×1016AO·cm-2·s-1的原子氧束流强度(氧原子能量约5ev)对制备的薄膜进行了不同时间(30、60、90和120min)的处理.通过X射线衍射(XRD)、透射光谱和拉曼光谱等分析手段对原子氧处理前后薄膜的结构及光学特性进行了分析.氧化锌薄膜的结晶质量随原子氧作用时间增加而显著变好,晶粒尺寸呈变大趋势,缺陷浓度明显降低;氧化锌薄膜的禁带宽度随原子氧作用时间增加而变小.采用本方法处理的氧化锌薄膜,可用于制备高性能的氧化锌基光电器件.     

ISP芯片在机舱自动化中的应用

介绍了PLD器件的基本概念及在系统可编程技术的特点;具体剖析了ISP芯片结构实例及ISP芯片在实船机舱自动化中的应用。实际运用表明,ISP芯片的使用可大大降低工作量和成本,具有广阔的应用前景。     

Influence of vanadium concentration on the microstructure and magnetic properties of V-doped ZnO thin films

Vanadium doped ZnO thin films (Zn_1 − xV_xO, where x = 0.05 or x = 0.13) were grown on c-cut sapphire substrates using pulsed laser deposition technique. Their structure and magnetic properties were examined in relation to the doping concentration. All deposited films were highly oriented along the c-axis and exhibited ferromagnetic behavior with a Curie temperature up to 300 K. The crystal structure was found to be better for layers with lower vanadium concentration. The films had a porous fine-grained microstructure and a column-like character as the V concentration was reduced. A weak dependence of magnetization on temperature was observed. The saturation magnetization was found to be strongly dependent on the crystal structure, grain size and V-ion concentration.     

PLD grown ZnO-K3[Fe(CN)6] composite thin film for biosensing application

Zinc oxide-potassium ferricyanide (ZnO-KFCN) composite film was prepared on ITO coated corning glass using pulsed laser deposition (PLD). The composite film has proved to be a suitable platform for enzyme immobilization. The composite matrix exhibits the advantages of ZnO along with enhanced redox property due to the presence of a mediator in the matrix. Glucose oxidase (GOx) has been chosen as the model enzyme for studying the application of the present matrix to biosensing. The sensing response of the bio-electrode, GOx/ZnO-KFCN/ITO/glass, towards glucose was studied by electrochemical and photometric techniques. The bio-electrode exhibits good linearity and low value of Michaelis-Menten constant. Due to efficient biosensing in a mediator-less system the present bio-electrode should lead to a hand held integrated lab-on-chip device.     

Protel99在逻辑电路中的应用

介绍了可编程逻辑器件(ＰＬＤ)应用和相应软件的发展及利用ＥＤＡ工具Ｐｒｏｔｅｌ９９的ＰＬＤ设计简单逻辑电路的一般方法。     

异步时序型PLD解析技术新算法研究

讨论了可编程逻辑器件（ＰＬＣ）可解析性的数学证明,并在此基础上给出一种异步时序列ＰＬＤ的解析新算法。理论分析和实验结果证明了该算法的高效性。