稀土元素在Ag-BaO光电薄膜中的作用

根据光电阴极的固溶胶理论,结合实验结果对稀土元素在Ag-BaO薄膜中的作用及其对光电发射性能的影响进行了分析。结果表明,增强光吸收和改善光电子输运条件是提高Ag-BaO薄膜光电发射电流的两个因素,而Ag纳米粒子的粒度对这两个因素都有重要影响。由于金属纳米粒子的光吸收是表面等离子激元的吸收,稀土元素在Ag-BaO薄膜中对Ag纳米粒子的细化,球化和密集的作用,使纳米粒子总表面增大,有利于增强薄膜的光吸收能力。Ag纳米粒子的细化还能够增大等效洛仑兹振子能量,降低金属微粒与半导体等效界面位垒,改善光电子输运条件,因而稀土元素在Ag-BaO薄膜中可以起到提高Ag-BaO薄膜的光电发射性能的作用。     

络合剂对ZnO薄膜的结构及其光催化性能的影响

采用溶胶-凝胶技术,以醋酸锌为前驱体,分别以乙醇胺、二乙醇胺、三乙醇胺为络合剂,在玻璃载玻片上制备了ZnO薄膜。利用X射线衍射(XRD)、原子力显微镜(AFM)、紫外-可见(UV-Vis)吸收光谱和X射线光电子能谱(XPS)等技术研究了以不同络合剂制备的ZnO薄膜的结构、表面形貌和光吸收性能以及表面化学态。以浸渍在ZnO薄膜表面的亚甲基兰为目标降解物评价薄膜的光催化活性。结果表明,乙醇胺为络合剂制备的ZnO薄膜具有良好的c轴择优取向,主要是由较小的晶粒扩散距离所致;以二乙醇胺为络合剂制备的ZnO薄膜显示较高的光催化活性,可能是由相对较好的光吸收性能以及较多的氧缺陷所致。     

Structure,optical, and magnetic properties of Mn-doped ZnO films prepared by sputtering

The microstructural, optical, and magnetic properties and room-temperature photoluminescence (PL) of Mn-doped ZnO thin films were studied. The chemical compositions were examined by energy dispersive X-ray spectroscopy (EDS) and the charge state of Mn ions in the ZnO:Mn films was characterized by X-ray photoelectronic spectrometry (XPS). From the X-ray diffraction (XRD) data of the samples, it can be found that Mn doping does not change the orientation of ZnO thin films. All the films prepared have a wurtzite structure and grow mainly along the c-axis orientation. The grain size and the residual stress were calculated from the XRD results. The optical transmittance of the film decreases with the increase of manganese content in ZnO. The room-temperature photoluminescence of the films shows that the intensity of near band energy (NBE) emission depends strongly on the Mn content. The hysteresis behavior indicates that the films with the Mn content below 9at% are ferromagnetic at room temperature.     

CdS薄膜/p-Si异质结的制备及其光伏性能研究

采用喷雾热解法在p型单晶硅(Si)上制备了硫化镉(CdS)薄膜,分支结构的金属Au作为正电极、金属铟作为背电极构成CdS薄膜/Si异质结光电器件.采用X-射线衍射(XRD)和原子力显微镜(AFM)对样品的晶体微结构及表面形貌进行表征,并通过紫外可见光谱研究CdS薄膜的光学吸收性能.最后,通过数字源表Keithley2400和高精度数字电桥TH2828测试异质结器件在不同光照强度(10、20、30、75、100、150 mW?cm^-2)下的伏安特性、光电导率和交流阻抗.     

Synthesis and characterization of Au@Pt nanoparticles

Aucore-Ptshell （Au@Pt） nanoparticles were synthesized at room temperature by reducing K2PtCl6 with hydrogen in the solution containing Au colloids and polyvinylpyrrolidone （PVP）. The particles obtained were characterized with UV-Vis, TEM and XPS techniques. UV-Vis spectra show that the surface plasmon absorption feature of Au colloids is significantly reduced with increasing the amount of reduced Pt. TEM images that the metals are found always appear as spherical nanoparticles and their sizes grow apparently due to the reduction of PtCl6^2- ions, indicating that Pt is deposited from solution onto Au particle surface and forms a Pt-layer with uniform thickness. In the XPS spectra, the signals of Au metal decrease due to the reductive deposition of Pt on the surface of the Au colloids. UV-Vis and XPS data are consistent in showing that when the amount of Pt in the AuPt colloids is increased to reach an overall atomic ratio of Pt/Au=2, the Pt deposits form a shell covering completely the surface of Au particles, demonstrating the core-shell structure of the synthesized AuPt particles.     

Effects of Fe content on the microstructure and properties of CuNi10FeMn1 alloy tubes fabricated by HCCM horizontal continuous casting

Heating-cooling combined mold (HCCM) horizontal continuous casting technology developed by our research group was used to produce high axial columnar-grained CuNi10FeMn1 alloy tubes with different Fe contents. The effects of Fe content (1.08wt%–2.01wt%) on the microstructure, segregation, and flushing corrosion resistance in simulated flowing seawater as well as the mechanical properties of the alloy tubes were investigated. The results show that when the Fe content is increased from 1.08wt% to 2.01wt%, the segregation degree of Ni and Fe elements increases, and the segregation coefficient of Ni and Fe elements falls from 0.92 to 0.70 and from 0.92 to 0.63, respectively. With increasing Fe content, the corrosion rate of the alloy decreases initially and then increases. When the Fe content is 1.83wt%, the corrosion rate approaches the minimum and dense, less-defect corrosion films, which contain rich Ni and Fe elements, form on the surface of the alloy; these films effectively protect the α-matrix and reduce the corrosion rate. When the Fe content is increased from 1.08wt% to 2.01wt%, the tensile strength of the alloy tube increases from 204 MPa to 236 MPa, while the elongation to failure changes slightly about 46%, indicating the excellent workability of the CuNi10FeMn1 alloy tubes.     

溶胶—凝胶法研制NiO薄膜

用溶胶－凝胶法合成了结构均匀而无裂纹的ＮｉＯ薄膜．借助Ｘ射线衍射仪和光学显微镜等手段，对ＮｉＯ薄的晶体结构和形貌进行了分析；利用光干涉仪测定了薄膜的厚度．讨论了浸沉涂布时垂直引上速度对薄膜厚度和成膜性的影响．为了制备结构均匀而无裂纹的ＮｉＯ薄膜，引上速度不应超过１２ｃｍ／ｍｉｎ．     

Effect of Ni on the corrosion resistance of bridge steel in a simulated hot and humid coastal-industrial atmosphere

The corrosion resistance of weathering bridge steels containing conventional contents of Ni (0.20wt%, 0.42wt%, 1.50wt%) and a higher content of Ni (3.55wt%) in a simulated hot and humid coastal-industrial atmosphere was investigated by corrosion depth loss, scanning electron microscopy-energy-dispersive X-ray spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical methods. The results showed that, with increasing Ni content, the mechanical properties of the bridge steel were markedly improved, the welding parameters were satisfactory at room temperature, and the corrosion resistance was enhanced. When the Ni content was low (≤ 0.42wt%), the crystallization process of the corrosion products was substantially promoted, enhancing the stability of the rust layer. When the Ni content was higher (~3.55wt%), the corrosion reaction of the steel quickly reached a balance, because the initial rapid corrosion induced the formation of a protective rust layer in the early stage. Simultaneously, NiO and NiFe₂O₄ were generated in large quantities; they not only formed a stable, compact, and continuous oxide protective layer, but also strongly inhibited the transformation process of the corrosion products. This inhibition reduced the structural changes in the rust layer, thereby enhancing the protection. However, when the Ni content ranged from 0.42wt% to 1.50wt%, the corrosion resistance of the bridge steel increased only slightly.     

Influence of Dispersion of Nano-ZnO Particles in Polymer Matrices on Properties of Relevant Nano Composite Fibers

IntroductionIt is well knownthat nanoparticles have rich propertiesand are useful for functional composites . The nanometricsize ,leading to huge specific surface area up to or morethan1 000m2/g ,andtheir unique properties have attractedintensive interests . Thus many articles have elucidated thepreparation of polymer matrix nanocomposites( PMNC)[1 6]. Polymers are very i mportant matricesbecause of their flexibility and easy processing .Nanoparticles i mpart larger-size congeries because of…     

射频溅射Si膜的微结构与光学性质研究

采用射频磁控溅射法,在300℃衬底温度下制备了不同厚度的Si薄膜,用X射线衍射仪、紫外-可见分光光度计和原子力显微镜(AFM)分别对薄膜的微结构、光学性质及表面形貌进行了测试分析.结果表明:不同时间下制备的Si膜均呈多晶状态;在中红外波段内出现了很强的Si-Si吸收峰;在紫外可见光范围,随着膜厚的增加,Si膜的透过率减弱;AFM测出Si膜的颗粒平均直径在5.65~8.41 nm之间.     

Ohmic contact properties of p-type surface conductive layer on H-terminated diamond films prepared by DC arc jet CVD

With the advantages of high deposition rate and large deposition area, polycrystalline diamond films prepared by direct current (DC) arc jet chemical vapor deposition (CVD) are considered to be one of the most promising materials for high-frequency and high-power electronic devices. In this paper, high-quality self-standing polycrystalline diamond films with the diameter of 100 mm were prepared by DC arc jet CVD, and then, the p-type surface conductive layer with the sheet carrier density of 1011-1013 cm?2 on the H-terminated diamond film was obtained by micro-wave hydrogen plasma treatment for 40 min. Ti/Au and Au films were deposited on the H-terminated diamond surface as the ohmic contact electrode, respectively, afterwards, they were treated by rapid vacuum annealing at different temperatures. The properties of these two types of ohmic contacts were investigated by measuring the specific contact resistance using the transmission line method (TLM). Due to the formation of Ti-related carbide at high temperature, the specific contact resistance of Ti/Au contact gradually decreases to 9.95 × 10?5 Ω·cm2 as the temperature increases to 820℃. However, when the annealing temperature reaches 850℃, the ohmic contact for Ti/Au is degraded significantly due to the strong diffusion and reaction between Ti and Au. As for the as-deposited Au contact, it shows an ohmic contact. After annealing treatment at 550℃, low specific contact resistance was detected for Au contact, which is derived from the enhancement of interdiffusion between Au and diamond films.     

Study of titanium nitride for Iow-e coating application

The paper reports our novel work on chemical vapor deposition coating of titanium nitride （TIN） thin film on glass for energy saving. TiN films were deposited on glass substrates by atmospheric pressure chemical vapor deposition （APCVD） using titanium tetrachloride （TiCl4） and ammonia （NH3） as precursors. As a result, TiN films with a thickness of 500 nm were obtained. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, atomic force microscopy （AFM）, four-point probe method and optical spectroscopy were respectively employed to study the crystallization, microstructure, surface morphology, electrical and optical properties of the coated TiN films. The deposited TiN films are of NaCI structure with a preferred （200） orientation. The particles in the film are uniform. The reflectivity of the TiN coating in the near-infrared （NIR） band can reach over 40%, the visible transmittance is approximately 60%, and the visible refiectivity is lower than 10%. The sheet electrical resistance is 34.5 Ω. According to Drude theory, the lower sheet resistance of 34.5 Ω gives a high reflectivity of 71.5% around middle-far infrared band. The coated films exhibit good energy-saving performance.     

Mg0.1Zn0.9O薄膜制备和光学性能研究

采用溶胶-凝胶技术在石英衬底上制备了Mg0.1Zn0.9O薄膜并研究了退火温度对薄膜结构、形貌和光学性能的影响.XRD结果表明,所有薄膜均呈六角钎锌矿结构,当退火温度高于700℃时,薄膜结晶质量变差;AFM结果显示,随退火温度升高,晶粒尺寸增大,当退火温度高于700℃时,薄膜表面出现团聚颗粒;UV-Vis结果表明,所有薄膜均在紫外区存在较强带边吸收,随退火温度升高吸收边红移;PL谱显示,所有薄膜均存在较强的紫外发射峰,随着退火温度升高,紫外发射峰逐渐红移且在700℃退火处理下紫外发射最强.     

Tunability of physical properties of (Cd:Zn)S thin film by Close Space Sublimation Process (CSSP)

The present paper reports on a systematic study of the influence of Zn alloying on the structural and optical properties of Cd1 xZnxS thin films. X-ray diffraction study for structural analysis reveals that the two binary compounds have been completely transformed into ternary compound with hexagonal (wurtzite) structure with preferred orientation along c-direction with (002) planes. The optical properties such as optical constants and band gap energy of the films were examined by using spectroscopic ellipsometer and Photospectrometery. It was found that the optical constants (n and k) decrease with the addition of Zn content in the alloy. It was also confirmed that the band gap increases with increasing Zn amount in the alloy and is attributed to quantum size effect in the grain size. Raman spectroscopy analysis shows one dominant phonon band at 326 cm 1, the so-called longitudinal optical (LO) mode for all the alloy composition (x). The appearance of a single phonon band in the Raman spectra established the formation of single phase hexagonal structured Cd1 xZnxS thin film. The LO band is asymmetrically broaden and high frequency shifted due to potential fluctuation caused by the dopant material. The AFM results showed that the surface roughness was decreased with increasing Zn content.     

Microstructure and properties of SiC gradiently coated Cf/C composites prepared by a RCLD method

The SiC gradiently coated carbon fiber/carbon (C_f/C) composites were prepared by a two-step rapid chemical liquid deposition (RCLD) method. The microstructure and properties of the composites were investigated using X-ray diffraction, scanning electron microscopy together with energy dispersive X-ray analysis, bending tests, and oxidation tests. The experimental results show that the surface layer of the composites is composed of SiC, pyrocarbon, and carbon fibers. Their inner area consists of pyrocarbon and carbon fibers. The SiC content gradiently decreases with increasing distance from the outer surface to the center of the composites. Furthermore, the thickness of the SiC layer increases with increasing tetraethylorthosilicate content and deposition time. SiC coatings have no significant influence on the bending strength of the composites. However, the oxidation resistance of the composites increases with increasing thickness of the SiC layer.     

Angular dependent NEXAFS study of the molecular orientation of PTCDA multilayers on Au （111） surface

The molecular orientation of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) multilayers adsorbed on Au (111) surface has been investigated using angular dependent O K-edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The significant angular dependence of important resonant structures (π* and σ*) reveals that PTCDA molecules adopt an ordered geometry on the substrate surface. The average tilt angle of the PTCDA molecular planes is 27°±10° from the Au (111) surface.     

氧浓度对磁控溅射Ti／WO3薄膜光学性能的影响

在不同氧浓度下,采用直流反应磁控溅射技术在玻璃基片上制备了Ti掺杂的WO3薄膜并在450℃退火。用X射线衍射（XRD）、分光光度计、台阶仪等对薄膜的结构和光学性质进行表征,分析了不同氧浓度对气敏薄膜的透光率、微结构及光学带隙的影响。结果表明,氧浓度增大,沉积速率越慢,膜厚度减小,薄膜的平均晶粒尺寸增大,晶面间距增大;透射率曲线随着氧浓度的增加逐渐向短波方向移动,表明薄膜的光学带隙宽度随氧浓度的增大而变大。     

Microstructures and optical properties of sol-gel derived TiO2 anatase thin films

TiO₂ anatase thin films on quartz substrates were prepared with sol-gel method. The dry gel films, made by spin coating 10 times, were calcined at various temperatures. From X-ray diffraction analyses, it is found that the anatase to rutile phase transformation temperature of the films is higher than 850°C, the films are preferentially oriented on (0 0 1) plane, i. e.c-axis oriented. The thickness, refractive indexes, absorption coefficients and extinction coefficients of the films were determined from UV-Vis transmission spectra of the films using a UV-Vis spectrophotometer. The thickness of the films is about 570 nm. The refractive indexes, absorption coefficients and the extinction coefficients of the present films are larger than the values of anatase films prepared by sputtering. This indicates that the films made with sol-gel method are very dense. Biography: LIU Zhong-chi(1967-), male, Master candidate. Research direction: non-linear optical materials.     

利用同步辐射XRD研究BiFeO3 外延多铁薄膜的微结构

使用脉冲激光沉积在SrTiO₃ 衬底上生长了不同厚度的BiFeO₃(BFO)薄膜, X 射线衍射分析表明薄膜是BFO 外延薄膜. X 射线反射率测量发现BFO 薄膜密度随着厚度的增加而增加, 同时薄膜表面存在厚度为数纳米的非设计覆盖层. 随着厚度的增加, BFO 薄膜由完全应变过渡到应变部分弛豫状态, 同时BFO 从四方相转变为单斜相.     

Effect of Mg content on the structural and optical properties of Mg<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Zn<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>O alloys

Mgx Zn1–x O thin films with x = 0, 0.11, 0.28, 0.44, 0.51, and 0.65 were grown by plasma-assisted molecular beam epitaxy on (0001) sapphire substrates. X-ray diffraction measurement reveals that phase separation of the Mgx Zn1–x O films occurred at x =0.44 and 0.51. Optical absorption spectra show that the absorption edges of the films shift to high-energy side with increasing Mg contents. In resonant Raman spectra, multiple-order Raman peaks originating from ZnO-like longitudinal optical phonons were obser...