Optical and Micro-Structural Properties of ZnO Thin Films Grown on Silicon Substrate by Pulsed Laser Deposition

ZnO thin films were deposited on n-Si (111) at various substrate temperatures and oxygen pressures by pulsed laser deposition (PLD) using a Nd∶YAG laser with the wavelength of 1064 nm. X-ray diffraction (XRD), photoluminescence (PL), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyze the microstructure, optical property and morphology of the ZnO thin films. A comparatively optimal crystallized ZnO thin film was obtained at the substrate temperature of 600 ℃ in oxygen pressure of 50 mTorr. The intensity of the luminescence strongly depends on the stoichiometry of the film as well as the crystalline quality.     

Prediction and Analysis on Oxidation of H13 Hot Work Steel

The understanding of oxidation behaviors on H13 steel was helpful to improve the service life and performance of hot work moulds and dies. Thermal-Calc Software was performed to calculate the oxidation phases on H13 steel along with different partial oxygen pressures in the interesting temperature range of 500-700 ℃. In this range H13 steel samples were treated respectively in different atmosphere including flowing water vapor （0.2 MPa）, normal pressure air （0.1 MPa） and low pressure air （0. 001 MPa）. The different oxidation films were detected with optical microscopy and X-ray diffraction. The microstructures and phase constitutions of the films formed in low pressure air were similar to those of the films formed in water vapor, and obviously different to those of the films formed in normal pressure air. The oxidation mechanisms of H13 steel in different atmosphere were also discussed.     

磁控溅射Ti/WO_3薄膜的微结构及光学性能

采用直流反应磁控溅射技术在玻璃基片上制备不同氧分压的Ti掺杂的WO3薄膜。用X射线衍射(XRD)、分光光度计、台阶仪等对薄膜的结构、光学性质进行表征;分析不同的氧分压对气敏薄膜透光率和结构的影响。结果表明,氧分压增大,膜厚减小,薄膜的平均晶粒尺寸增大,晶面间距增大,光学带隙变小。并用包络线法和经验公式法计算出薄膜的光学常数,结果表明,折射率和消光系数随氧分压的增加而增大。     

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.     

Sputtering-pressure dependence of magnetic properties in amorphous Tb_（40）（FeCoV）_（60） films

The Tb40(Fe49Co49V2)60 films were fabricated by magnetron cosputtering from a multiple target arrangement at different argon pressures.The samples were investigated using X-ray diffraction,magnetic force microscope and vibrating sample magnetometer.A strong perpendicular anisotropy was obtained for the sample prepared at 0.4 Pa.The easy direction of magnetization could be turned from perpendicular to in-plane direction either at high working pressures(P Ar >2.0 Pa) or by annealing at temperatures higher than 250 °C.An excellent magnetic softness with coercivity below 3 mT and saturating field of 20 mT in film-plane direction was obtained for the sample prepared at 0.7 Pa and then annealed at 350 °C.     

Effect of cerium addition on oxidation behavior of 25Cr20Ni alloy under low oxygen partial pressure

The influence of Ce addition on the oxidation behavior of 25Cr20Ni alloy at 950 oC under low oxygen partial pressure was inves-tigated. The oxidized samples were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and scratch tester to obtain the oxide phases, morphology, thickness, composition and adhesion property of the oxide scales. The experiment results indicated that a small amount of Ce addition (0.02 wt.% or 0.05 wt.%) promoted oxidation resistance and inhibited the growth of the needlelike oxide. The Ce addition also decreased the formation of MnCr2O4 but promoted the SiO2 formation un-derneath the Cr2O3, which largely contributed to the improvement of oxide scale spallation resistance. For the sample with 0.3 wt.% Ce addi-tion, the oxidation rate significantly increased and the spallation resistance of the oxide scale decreased.     

Phase control of magnetron sputtering deposited Gd2O3 thin films as high-κ gate dielectrics

Gd2O3 thin films as high-κ gate dielectrics were deposited directly on Si(001) substrates by magnetron sputtering at a pressure of 1.3 Pa and different temperatures. X-ray diffraction results revealed that all the films grown from 450 to 570℃ were crystalline, and the Gd2O3 thin films consisted of a mixture of cubic and monoclinic phases. The growth temperature was a critical parameter for the phase constituents and their relative amount. Low temperature was favorable for the formation of cubic phase while higher temperature gave rise to more monoclinic phase. All the Gd2O3 thin films grown from different temperatures exhibited acceptable electrical properties, such as low leakage current density (JL) of 10-5 A/cm2 at zero bias with capacitance equivalent SiO2 thickness in the range of 6-13 nm. Through the comparison between films grown at 450 and 570℃, the existence of monoclinic phase caused an increase in JL by nearly one order of magnitude and a reduction of effective dielectric constant from 17 to 9.     

氧化铍金刚石膜及其导热性能

提高氧化铍的热导率,既能助其开拓新的发展空间,又能满足电子器件的散热需求,因而利用热丝化学气相沉积法在氧化铍上沉积得到与基体串、并联方式不同的、利于提高导热率的各种金刚石薄膜.通过扫描电镜和原子力显微镜观察薄膜表面的晶体形貌:采用X射线衍射仪分析薄膜成分;借助热物性激光测试仪测量金刚石膜/氧化铍基复合体的热扩散系数,并计算其热导率.结果表明:镀膜后可使氧化铍的热导率提高12.1%～34.4%;基体预处理方法、金刚石膜和氧化铍基体的串、并联方式对复合体的热导率均有较大影响.     

沉积压力对磁控溅射Mg薄膜结构的影响

采用直流磁控溅射方法在氧化锆固体电解质表面制备了Mg金属薄膜,利用XRD和SEM研究了沉积压力(0.9～2.1Pa)对薄膜形貌和结构的影响.结果表明:随着沉积压力的提高,薄膜结晶程度逐渐变差,晶粒尺寸减小,表面粗糙度增大;薄膜呈(002)择优生长的柱状晶结构,且随着沉积压力的提高薄膜厚度先增加后减小.     

Effects of Hydrogen Ion Implantation on TiC-C Coating of Stainless Steel

Titanium carbide coatings are widely used as various wear-resistant material.The hydrogen erosion resistance of TiC-C films and the effect of hydrogen participation on TiC-C films were studied.Seventy-five percent TiC-C films are prepared on stainless steel surface by using ion mixing,where TiC-C films are deposited by rf magnetron sputtering followed by argon ion bombardment.The samples are then submitted to hydrogen ion implantation at 1.2×10-3 Pa.Characterization for the 75% TiC-C films was done with SIMS,XRD,AES,and XPS.Secondary ion mass spectroscopy (SIMS) was used to analyze hydrogen concentration variation with depth,X-Ray diffraction (XRD) was used to identify the phases,and Auger electron spectra (AES) as well as X-ray photoelectron spectra (XPS) were used to check the effects of hydrogen on shifts of chemical bonding states of C and Ti in the TiC-C films.It is found that TiC-C films on stainless steel surface can prevent hydrogen from entering stainless steel.     

高温还原性气氛下TiOx-SiO2-MgO系结晶过程的研究

实验通过定组成的H2/CO2混合气控制氧分压,在温度为1873 K、1673 K、1473 K,氧分压为1.22×10-8~2.18×10-12 Pa、4.92×10-8~8.79×10-12 Pa的范围内,研究了TiOx-SiO2-MgO 系的析出相.结合XRD和EDS分析并对比汪大亚等人的研究可知,当氧分压较高（PCO∶PCO2=5∶1）时,对于初始成分TiO2∶MgO∶SiO2摩尔比为60∶25∶15的试样,在1873 K 和1673 K 时的析出相为TiO2,在1473 K 时其析出相为MgTi2O5;对于初始成分TiO2∶MgO∶SiO2摩尔比为60∶15∶25的试样,在1873 K时其析出相为TiO2,在1673 K和1473 K时析出相为MgTi2O5.而当氧分压较低（PH2∶PCO2=600∶1、300∶1、150∶1）时,2种不同成分的试样在不同温度下的析出相均为黑钛石,并且随着氧分压的降低,黑钛石中的Mg 含量逐渐减少.     

Nanocrystalline Diamond Films Deposited by Electron Assisted Hot Filament Chemical Vapor Deposition

Nanocrystalline diamond films were deposited on polished Si wafer surface with electron assisted hot filament chemical vapor deposition at 1 kPa gas pressure, the deposited films were characterized and observed by Raman spectrum, X-ray diffraction, atomic force microscopy and semiconductor characterization system. The results show that when 8 A bias current is applied for 5 h, the surface roughness decreases to 28.5 nm. After 6 and 8 A bias current are applied for 1 h, and the nanocrystalline films deposition continue for 4 h with 0 A bias current at 1 kPa gas pressure. The nanocrystalline diamond films with 0.5×109 and 1×1010 Ω·cm resistivity respectively are obtained. It is demonstrated that electron bombardment plays an important role of nucleation to deposit diamond films with smooth surface and high resistivity.     

Grain Size and Wettability of TiO2/SiO2 Photocatalytic Composite Thin Films

The uniform transparent TiO2/SiO2 photocatalytic composite thin films are prepared by sol-gel method on the soda lime glass substrates, and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), BET surface area, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that the addition of SiO2 to TiO2 thin films can suppress the grain growth of TiO2 crystal, increase the hydroxyl content on the surface of TiO2 films, lower the contact angle for water on TiO2 films and enhance the hydrophilic property of TiO2 films. The super-hydrophilic TiO2/SiO2 photocatalytic composite thin films with the contact angle of 0-° are obtained by the addition of 10%-20% SiO2 in mole fraction.     

Structure and chemical states of highly eptiaxial CeO2（001） films grown on SrTiO_3 substrate by laser molecular beam epitaxy

Highly epitaxial and pure（001）-oriented CeO2 films were grown on SrTiO3（001） substrates by laser molecular beam epitaxy method without any gas ambient.Layer-by-layer epitaxial growth mode of CeO2 was confirmed by in situ reflection high-energy electron diffraction（RHEED） observations.High-resolution X-ray diffraction（HRXRD） and high-resolution transmission electron microscopy（HRTEM） results indicated the STO（100）//CeO2（100）,STO[100]//CeO2 [110] epitaxial relationship for out-of-plane and in-plane,respectively.The formation mechanism of the epitaxial film was also discussed in the light of a theoretical model.Chemical states of the LMBE ceria films were evaluated and evidences for the existence of Ce3＋and oxygen vacancies were presented.     

Synthesis of ZnFe2O4 nanosized powders by pulsed wire discharge

Nanocrystalline zinc ferrite (ZnFe₂O₄) powders have been synthesized successfully by high-power short-pulse electric discharge of Fe and Zn wires in oxygen gas. The powders were characterized by X-ray diffraction and transmission electron microscopy (TEM). Mean size of the obtained particles determined by both BET and TEM was 12 to 56 nm depending on the oxygen pressure. X-ray analysis showed that the zinc ferrite spinel was clearly obtained. __________ Translated from Poroshkovaya Metallurgiya, Nos. 7–8(450), pp. 3–6, July–August, 2006.     

Preparation,characterization and infrared emissivity study of Ce-doped ZnO films

Ce-doped ZnO films were prepared by the sol-gel method with spin coating onto glass substrates.Zinc acetate dihydrate,ethanol,diethanolamine and cerium nitrate hexahydrate were used as starting material,solvent,stabilizer and dopant source,respectively.Structure and microstructure of the films were characterized with X-ray diffraction(XRD),field emission-scanning electron microscopy(FE-SEM) and the energy dispersive X-ray spectrometry(EDS).The infrared properties were also investigated.It was found that Ce-...     

Growth and interface of amorphous La2Hf2O7/Si thin film

Amorphous La2Hf2O7 thin films were deposited on Si(100) substrate by pulsed laser deposition (PLD) method under different con-ditions. The interfacial states of the La2Hf2O7/Si films were studied by synchrotron X-ray reflectivity (XRR) and X-ray photoelectron spec-troscopy (XPS). When grown under vacuum condition, silicate, silicide and few SiOx were formed in the interface layer. However, the Hf-silicide formation could be effectively eliminated by the ambient oxygen pressure during film growth. The result revealed that the La2Hf2O7/Si interlayer was intimately related with growth condition. Insufficient supply of oxygen would cause Hf-silicide formation at the interface and it could be most effectively controlled by the ambient oxygen pressure during film growth.     

稀土-硼共渗预处理对YG6表面金刚石薄膜质量的影响

分别对YG6(WC-wt.6%.Co)硬质合金基体表面进行常规固态渗硼和固态稀土(CeO2)共渗处理,再以甲烷和氢气为反应气体,采用热丝化学气相沉积法在合金基体表面沉积金刚石膜,通过调控灯丝功率和进气总流量制备微米晶或纳米晶金刚石膜。利用场发射扫描电镜、X射线衍射仪、激光拉曼光谱仪和洛氏硬度计对渗硼基体和金刚石膜进行检测分析,研究YG6硬质合金基体稀土硼共渗与常规固态渗硼处理对微米晶金刚石膜与纳米晶金刚石膜的物相组成、结构形貌和附着性能的影响。结果表明,与常规固态渗硼处理相比,稀土(CeO2)硼共渗样品表面残留物较少,沉积的金刚石膜样品表面粗糙度低,在1 000 N载荷下薄膜无剥落现象,表现出较好的附着性能;纳米晶金刚石膜的生长速率低于微米晶金刚石膜,但其附着性能明显优于微米晶金刚石膜。     

Photocatalytic degradation of Rhodamine B under visible light with Nd-doped titanium dioxide films

Microporous titanium dioxide films were prepared by the sol-gel methods on glass substrates, using tetrabutyl titanate as source material. In order to absorb the visible light and increase the photocatalytic activities, different concentrations of neodymium ions (Nd/Ti molar ratio was 0.5%, 0.7%, 0.9%, and 1.1% respectively) were added into the sol. X-ray diffraction (XRD), X-ray photoelectron spectros-copy (XPS), and atom force microscopy (AFM) were applied to characterize the modified films. A kind of typical textile industry pollutant (Rhodamine B) was used to evaluate the photocatalytic activities of the films under visible light. The results showed that the activities of the films were improved by doping Nd ions into the sol.     

Structure and Properties of TiO2-CeO2 Films Deposited on Soda-Lime Silicate Glass Substrates by R.F.Magnetron Sputtering

TiO2-CeO2 films were deposited on soda-lime glass substrates at different ratio of O2 to Ar (0.10, 0.15,0.20) by R. F. magnetron sputtering. The structure, surface composition, UV-visible spectrum of the films were measured by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and spectrometer. The results show that the films are amorphous, and the relative molar ratio of Ce to Ti is higher than that of the target at lower ratio of O2 to Ar. Only tetravalent Ti 4 and Ce 4 ions are present in the films, and the obtained TiO2 -CeO2 films appear good uniformity and high density. The films deposited on the glass can shield ultraviolet light without significant absorption of visible light.