沉积温度对IMO透明导电薄膜光电性能的影响

采用射频磁控反应溅射法在K9玻璃衬底上制备了掺钼氧化铟(Mo:In2O3,IMO)透明导电薄膜,研究了不同沉积温度条件下IMO薄膜的晶体结构、形貌及光电性能。结果表明:不同沉积温度下IMO薄膜均具有(222)择优取向。随着沉积温度的升高,IMO薄膜的载流子浓度增大、载流子迁移率增大、电阻率减小;沉积温度为350℃时,薄膜的最低电阻率为6.9×10-4Ω.cm,载流子浓度为2.15×1020cm-3,迁移率为45 cm2V-1s-1。在可见及近红外区,IMO薄膜的平均透过率大于80%以上。在近红外区,薄膜透过率随沉积温度的升高而增大;在中红外区,由于载流子的吸收,薄膜透过率迅速下降。     

透明导电IMO薄膜的载流子迁移率研究

采用van der Pauw法、等离子振荡波长法和光谱拟合法等三种方法对IMO(In2 O3 ∶Mo)薄膜和ITO(In2 O3 ∶Sn)薄膜的载流子迁移率进行了测量和比较。结果表明 ,IMO薄膜的载流子迁移率高达 10 0cm2 V-1s-1以上 ,远超过已报导的其他掺杂透明导电氧化物 (TCO)薄膜的载流子迁移率 ;IMO薄膜的载流子有效质量约为电子静止质量的 0 35倍 ;IMO薄膜的高载流子迁移率主要是由于载流子受到的散射作用较弱所引起。这无法用通常的掺杂TCO薄膜的载流子散射理论来解释 ,为此引入复合效应进行分析。在ITO薄膜中 ,每形成一个电中性复合粒子 ,就会使两个掺杂的Sn4 失去贡献载流子的电活性 ;而在IMO薄膜中 ,即使一个掺杂Mo6 与晶格间隙中的一个O2 -结合成复合离子后 ,该复合离子仍然会贡献出一个载流子 ,故薄膜中形成的电中性复合粒子数目较少 ,从而导致价态差为 3的IMO薄膜中的电中性复合粒子对载流子的散射远低于价态差为 1的ITO薄膜 ,因此 ,IMO薄膜有可能获得较高的载流子迁移率     

透明导电IMO薄膜的载流子迁移率研究

采用van-der-Pauw法、等离子振荡波长法和光谱拟合法等三种方法对IMO(In2O3：Mo)薄膜和ITO(In2O3：Sn)薄膜的载流子迁移率进行了测量和比较。结果表明，IMO薄膜的载流子迁移率高达100cm^2V^-1s^-1以上，远超过已报导的其他掺杂透明导电氧化物（TCO）薄膜的载流子迁移率；IMO薄膜的载流子有效质量约为电子静止质量的0.35倍；IMO薄膜的高载流子迁移率主要是由载流子受到的散射作用较弱所引起。这无法用通常的掺杂TCO薄膜的载流子散射理论来解释，为此引入复合效应进行分析。在ITO薄膜中，每形成一个电中性复合粒子，就会使两个掺杂的Sn^4 失去贡献载流子的电活性；而在IMO薄膜中，即使一个掺杂Mo^6 与晶格间隙中的一个O^2-结合成复合离子后，该复合离子仍然会贡献出一个载流子，故薄膜中形成的电中性复合粒子数目较少，从而导致价态差为3的IMO薄膜中的电中性复合粒子对载流子的散射远低于价态差为1的ITO薄膜，因此，IMO薄膜有可能获得较高的载流子迁移率。     

氧分压对掺钼氧化铟透明导电薄膜光电性能的影响

采用射频磁控反应溅射法在k9玻璃衬底上制备了In2O3∶Mo(IMO)透明导电薄膜,分析了不同氧分压条件下IMO薄膜的晶体结构、化学成分及光电性能.结果表明:不同氧分压下制备的IMO薄膜具有不同晶粒的取向性;随着氧分压的增加,薄膜的载流子浓度、载流子迁移率先增加后减小;薄膜的电阻率呈现先增加再减少然后再增加的趋势.在可...     

退火温度对铜铟镓硒薄膜电学性能的影响

使用磁控溅射铜铟镓硒(CuIn1-xGaxSe2,CIGS)四元陶瓷靶材制备沉积态预制膜,在240-550℃对预制膜进行退火处理,着重研究了退火温度对薄膜电学性能(载流子浓度及迁移率)的影响。结果表明:退火温度低于270℃时薄膜中存在CuSe低电阻相,CIGS薄膜的载流子浓度在1017-1019cm-3,迁移率在0.1 cm2·V-1·s-1左右,不适于作为太阳电池的吸收层;当退火温度高于410℃时薄膜中不存在CuSe相,薄膜具有10 cm2·V-1·s-1左右的较高迁移率,载流子浓度在1014-1017cm-3;退火温度高于410℃时,随着退火温度的升高薄膜晶粒长大,结晶性增强,此时薄膜内部缺陷减少,载流子浓度升高;对于用作太阳电池吸收层的CIGS,从载流子浓度及迁移率的角度评判,合适的退火温度区间为450-550℃。     

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%.     

共掺杂n型CVD金刚石薄膜的结构和性能

利用微波等离子体化学气相沉积(MPCVD)技术制备硫掺杂及硼/硫共掺杂n型金刚石薄膜,探讨n型CVD金刚石薄膜的特性和共掺杂机理.研究结果显示:随着单一硫(S)掺杂含量的增加,金刚石薄膜导电激活能降低,薄膜生长速率减小,薄膜中非金刚石结构相增多;硼/硫(B-S)共掺杂有利于增加硫在金刚石中的固溶度,提高硫在金刚石晶体中的掺杂率,降低金刚石薄膜的导电激活能(在0.26～0.33eV);与单一S掺杂相比较,B-S共掺杂金刚石薄膜生长速率低,薄膜质量和晶格完整性好;霍耳效应测试表明硫掺杂和硼/硫共掺杂金刚石薄膜具有n型导电特征,载流子浓度在1016-1018/cm3之间,载流子迁移率在7～80cm2V-1s-1之间.采用B-S共掺杂技术有利于提高CVD金刚石薄膜的晶格完整性,使得B-S共掺杂金刚石薄膜具有更高的载流子迁移率.     

掺钼氧化锌透明导电薄膜光学性质研究

采用直流磁控反应溅射制备了掺钼氧化锌透明导电薄膜。研究了掺钼氧化锌薄膜的结构、表面形貌及其光学和电学性能。原子力显微镜扫描显示薄膜表面较为平整致密。制备出的掺钼氧化锌薄膜最低电阻率为9.4×10-4Ω.cm,相应载流子迁移率为27.3cm2V-1s-1,载流子浓度为3.1×1020cm-3。在可见光区域的平均透射率大于85%,折射率(550nm)为1.853,消光系数为7.0×10-3。通过调节氧分压可以调节薄膜载流子浓度,禁带宽度随载流子浓度的增加由3.37增大到3.8eV,薄膜的载流子有效质量m*为0.33倍的电子质量。     

新型透明导电ZnO:Mo薄膜

采用直流磁控反应溅射技术成功制备了新型ZnOMo(ZMO)透明导电薄膜.研究了钼掺杂量和基片温度等参数对ZMO薄膜结构和光电性能的影响.结果表明,薄膜的结构和光电性能与钼含量以及基片温度有关.x光衍射图谱(XRD)显示薄膜具有六角纤锌矿结构,并且在基片温度为200℃,钼含量(Mo/Zn Mo)为1.5wt%时薄膜具有较好的c轴取向.制备出的ZMO薄膜最低电阻率为1.97×10-3 Ω·cm,相应载流子迁移率达37.0 cm2V-1s-1,载流子浓度为8.57×1019 cm-3,在可见光区域的平均透射率达到80%左右.     

膜厚对AZO∶Si薄膜性能的影响

近年来,Si基ZnO∶Al透明导电薄膜界面处Si的渗透对薄膜性能的影响引起了人们的关注。本文采用射频磁控溅射法,在石英和Si衬底上沉积了不同厚度的Al、Si弱掺杂(1wt.%)的ZnO薄膜(AZO∶Si),系统研究了膜厚(等价于Si的渗透深度)对薄膜电学、光学性质的影响。结果显示,膜厚在几十nm时,薄膜的电阻率、载流子浓度和迁移率都强烈地依赖于膜厚,在膜厚为19nm时,载流子浓度和迁移率接近最小,电阻率较大,且呈现p型导电特性。随着膜厚增加,载流子浓度和迁移率都变大,电阻率减小并趋于稳定,膜厚在396nm附近时电阻率最小是7×10-3Ωc#m,此时的载流子浓度和迁移率分别是1.54×1020cm-3和5.66cm2 V-1s-1。膜厚达300nm以上时,Si的影响已可忽略。结合薄膜的X射线衍射(XRD)图谱、X射线光电子能谱(XPS)和紫外-可见光(UV-Vis)透射光谱探讨了膜厚(Si的渗透深度或过渡层厚度)对薄膜性能的影响及其相关机制。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Effect of Oxide Assisted Metal Nanoparticles on Microstructure and Morphology of Gallium oxide Nanowires

Several researches have been reported about the characteristic of β-Ga2O3 nanowires which was synthesized on nickel oxide particle. But indeed, recent researches about synthesis of β-Ga2O3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst. In this work, Gallium oxide (β-Ga2O3 ) nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700 - 1000℃ using the iron, nickel, copper, cobalt and zinc oxide as a catalyst, respectively. The β-Ga2O3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850, 900 and 950℃ in all the catalysts. But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst. As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods, and its diameter increased. From these results, we could be proposed that the growth mechanism of β-Ga2O3 nanowires was changed with synthesis temperature of nanowires. Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM, FE-SEM, EDX and XRD.     

The Influence of Nitrogen and Boron Implant into Silicon Substrate on the Phase and Internal Stress of c-BN Films

Cubic boron nitride(c-BN) film was deposited on a Si (100) substrate by the RF-magnetron sputtering.The mainly problems for fabrication of c-BN films are the low purity and high intrinsic compressive stress. In order to solve the two problems, the c-BN film with the buffer interlayer was deposited on the substrate which had been implanted with nitrogen and/or boron ions. The results show: the implantation of nitrogen ions can obviously increase c-BN content and reduce the internal stress slightly; while the implantation of boron shows no obvious improvement to the content of c-BN, which can reduce the internal stress in the film obviously. In addition, it is suggested that the implantation of nitrogen and boron shows the best result, which not only can increase the content of c-BN, but also reduce the internal stress in the c-BN film obviously.