Au/Gd多层膜的制备和表征

介绍了用磁控溅射法制备Au/Gd(金/钆)多层膜的初步实验结果.在摸索出的工艺条件下,采用计算机定时控制膜厚的方法,按照设计的周期结构(设计周期厚度10nm,Au/Gd=5nm/5nm,总周期数为25)制备了界面清晰、表面光滑的多层膜样品.X-Ray衍射仪小角衍射测试的周期厚度为9.95nm,和设计值十分吻合,原子力显微镜(AFM)的检测表明,薄膜的表面粗糙度小于1.7nm.     

纳米材料

正科学家首次创造出双层硼烯材料比石墨烯更"逆天"据报道,美国西北大学工程师首次创造出一种双层原子厚度的硼烯,打破了硼在单原子层限制之外形成非平面团簇的自然趋势。该研究发表在《自然·材料》杂志上。硼烯是一种单原子厚的硼薄片,是由硼原子构成的单原子层厚的二维材料,比石墨烯更强、更轻、更柔韧,被科学界寄予厚望,     

不同工艺条件下Ni／Ti周期性多层膜界面粗糙度的研究

本文采用直流磁控溅射法制备了一系列Ni／Ti周期性多层膜,用X射线小角衍射进行周期结构分析。主要研究了不同的制备工艺条件下,Ni／Ti周期性多层膜周期厚度和界面粗糙度的变化规律,从而归纳出最佳的溅射工艺条件。研究发现采用移动模式制备出的多层膜,其周期厚度的均匀性以及界面粗糙度均优于固定模式;并且在移动模式下制备的多层膜其界面粗糙度,随基片架移动速率的增大而减小。     

基于(100)定向金刚石薄膜的辐射探测器研究

采用微波等离子体化学气相沉积（MPCVD）方法制备了100μm米厚高质量(100)定向金刚石薄膜. 利用(100)定向金刚石薄膜成功制备了α粒子探测器, -100V偏压下电荷平均收集效率为37.7%, 最大的电荷收集效率达到60%以上. 在此基础上, 通过在α粒子探测器条状电极面蒸镀一层合适厚度的硼(10B)膜转化层, 成功研制了金刚石中子探测器. 镀硼之后探测器对中子有明显的响应, 在1V/μm电场下, 对252Cf中子的能量分辨率达到9.3%,探测效率达到1.67%. 同时还研究了电场强度和硼(10B)层厚度对器件探测效率的影响规律. 在厚度<1.5μm时, 随着厚度的增加, 探测效率上升, 当厚度>1.5μm时, 探测效率下降.     

硅中氮离子注入的研究进展

综述了硅中氮离子注入的应用和研究进展。主要讨论了氮离子注入形成SOI层的原理、质量的影响因素和电学性能；介绍了氮离子注入在制备超薄氧化栅极及其抑制掺杂杂质原子特别是硼原子扩散等方面的研究和应用。     

对金属陶瓷硬质覆层材料界面层扩散的研究

根据三元硼化物金属陶瓷硬质覆层材料6B的制备工艺,研究了该硬质覆层材料界面过渡层的形成机理.利用菲克第二定律,建立了其界面过渡层扩散厚度的理论模型,根据该模型对6B的界面过渡层厚度进行了计算.利用扫描电镜和电子探针对6B界面过渡层的扩散机理和扩散过程进行了试验研究,试验研究结果与理论分析结果相符.根据理论分析和试验结果确定了一定制备工艺条件下该硬质覆层材料界面过渡层扩散组元的扩散系数.     

二维层状WS2/MoS2异质结中镧系近红外光子发射与能量转移（英文）

镧系离子由于其独特的光子特性而备受关注.二维层状范德华异质结的光电特性和器件性能受到界面耦合的极大影响,该异质结通常是由两层或多层过渡金属二硫化物(TMD)堆叠而成.本文通过两步合成构建了镧系离子掺杂的层状WS2/MoS2异质结.所制备的掺杂薄膜是在晶圆衬底上生长的高度织构纳米片.更重要的是,由于两个TMD层中镧系离子之间的能量转移,层状异质结的结构减少了因均匀掺杂或浓度猝灭而引起的无益交叉松弛,所制备的堆叠异质结能够在近红外通讯窗口产生高效的光子发射.镧系掺杂和能量转移的研究结果表明,镧系离子可以有效地扩展TMD薄膜的发射波段及其异质结构.本工作所发展的镧系掺杂TMD异质结有助于进一步研究原子级超薄近红外光子器件.     

Q235钢固体粉末渗硼及渗层生长动力学行为

各类材料渗硼工艺不同,硼的扩散也不同,其中有许多现象往往不能定量分析.采用固体粉末法对Q235钢进行了渗硼,得到的渗硼层为锯齿状,垂直于钢表面楔入基体.用sigma Plot 10.0软件对试验数据进行了分析和拟合,得出了渗硼层等厚度图,为制定渗硼工艺提供了依据:利用此图,既可以对设定的渗硼时间和温度预测渗硼层厚度,又可以用一定的固体渗硼厚度值确定渗硼时间和温度.通过动力学研究得到了渗层相组成为单一的Fe2B相硼,在不同温度下的扩散速率常数:K800℃=1.074×10-13m2/s,K850℃=1.622×10-13m2/s,K900℃=3.921×10-13m2/s,平均扩散激活能为134.473 kJ/mol.     

硼在纳米晶氧化钛中的掺杂状态

用两步水热合成方法制备硼掺杂纳米晶TiO2粉体,研究了硼在纳米晶氧化钛中的掺杂状态.结果表明,一定硼源加入和水热过程是在TiO2粉体中实现有效硼掺杂的必要条件.当硼含量较高时,硼原子在Ti02表面形成具有可调节Ti02能带结构的B-Ti-O表面掺杂态,可有效提高TiO2的可见光吸收性能,而且可见光吸收强度随着硼掺杂量的增大而提高.     

湿法去除N型硅硼扩散过程形成的富硼层

硼扩散被广泛应用于n型硅基的p-n结制结工艺,然而硼扩散难免会在硅片表面形成一层很薄的的富硼层,该层由于富集无活性硼原子会严重影响电池性能。本研究制备HF-HNO3化学腐蚀液来去除富硼层,采用该方法去除富硼层后的硅片少子寿命从26.829μs增加到69.106μs;WCT-120测得一个光照下Voc从610mv增加到了625mv,发射极饱和电流密度显著降低;去除富硼层后的方块电阻均匀性表现良好,甚至比采用传统后氧化法更具优势。虽然反射率有细微增加,但是对于镀完氮化硅减反膜后腐蚀所带来的反射率升高只有0.13%,因此,认为该方法可以成功应用到富硼层的去除中。     

A direct metal transfer method for cross-bar type polymer non-volatile memory applications

Polymer non-volatile memory devices in 8 × 8 array cross-bar architecture were fabricated by a non-aqueous direct metal transfer (DMT) method using a two-step thermal treatment. Top electrodes with a linewidth of 2?μm were transferred onto the polymer layer by the DMT method. The switching behaviour of memory devices fabricated by the DMT method was very similar to that of devices fabricated by the conventional shadow mask method. The devices fabricated using the DMT method showed three orders of magnitude of on/off ratio with stable resistance switching, demonstrating that the DMT method can be a simple process to fabricate organic memory array devices.     

Superplastic boronizing of duplex stainless steel under dual compression method

In this work, SPB of duplex stainless steel (DSS) under compression method is studied with the objective to produce ultra hard and thick boronized layer using minimal amount of boron powder and at a much faster boronizing time as compared to the conventional process. SPB is conducted under dual compression methods. In the first method DSS is boronized using a minimal amount of boron powder under a fix pre-strained compression condition throughout the process. The compression strain is controlled in such a way that plastic deformation is restricted at the surface asperities of the substrate in contact with the boron powder. In the second method, the boronized specimen taken from the first mode is compressed superplastically up to a certain compressive strain under a certain strain rate condition. The process in the second method is conducted without the present of boron powder. As compared with the conventional boronizing process, through this SPB under dual compression methods, a much harder and thicker boronized layer thickness is able to be produced using a minimal amount of boron powder.     

Characterization deep boron diffused p++ silicon layer

In recent years the boron impurity-based dissolved wafer process has been repeatedly demonstrated as a powerful tool for forming single crystal Si microstructures. However, there is very little report on detailed characterization of the deep boron diffused silicon layer. This paper presents the optimization of deep boron diffused p⁺⁺ silicon layer (>10?μm thick) of boron concentration above 5?×?10¹⁹?atoms/cm³. Detailed characterization of the p⁺⁺ silicon layers, by using high resolution x-ray diffraction, secondary ion mass spectrometry, secondary electron micrograph are done. The optical behaviour of the p⁺⁺ layers in mid-IR range is also carried out. The stress generated due to the deep diffusion is estimated to be 822?MPa by Raman spectroscopy.     

Poly-Si films with long carrier lifetime prepared by rapid thermal annealing of Cat-CVD amorphous silicon thin films

Polycrystalline silicon (poly-Si) films thicker than 1.5 μm, consisting of dense small grains called nano-grain poly-Si (ngp-Si), are formed by flash lamp annealing (FLA) of amorphous silicon (a-Si) films prepared by catalytic chemical vapor deposition (Cat-CVD) method. Crystallinity of the ngp-Si films can be controlled by changing lamp irradiance. Secondary ion mass spectroscopy (SIMS) profiles of dopants in the ngp-Si films after FLA shows no serious diffusion. A minority carrier lifetime of over 5 μs is observed from these ngp-Si films after defect termination process using high pressure water vapor annealing (HPWVA), showing possibility of application for high-efficient thin film solar cells.     

Few layers of graphene as transparent electrode from botanical derivative camphor

Here, we report synthesis of large area graphene sheets by control pyrolysis of solid botanical derivative camphor (C₁₀H₁₆O) and fabrication of transparent electrodes. Raman study shows highly ordered graphene sheet with minimum defects. Second order Raman spectrum shows that graphene layers are more than single layer and can be controlled with amount of camphor pyrolyzed. Transmission electron microscopic images show presence of 4 layers for thinner and 13 layers for thicker graphene sheets. Transferred graphene sheets on glass substrates show very good transparency in wide range of wavelength (0.3-2 μm). Electrical measurements of the graphene sheets show thickness dependent sheet resistance. A sheet resistance of 203 Ω/sq is obtained at a transmittance of 63.5% of the graphene sheet. The technique to fabricate few layer of graphene as transparent electrode from camphor is both viable and scalable for potential large area optoelectronic applications.     

稀土热扩渗在注塑模具中的运用

在＂以塑代钢＂、＂以塑代木＂的必要趋势下,注塑模具的发展就更显得重要,尤其是最能代表生产力的长寿命、高精度的模具。文中简要介绍了稀土热扩渗技术在注塑模具表面处理中的运用,并将其与未添加稀土渗剂的传统热扩渗技术相比较,全面有效的说明了稀土热扩渗的优势,有效催渗,并能增加渗层厚度与硬度,提高注塑模具的使用寿命与精度。     

Effect of B/C ratio on the physical properties of highly boron-doped diamond films

Highly boron-doped diamond films were deposited on silicon substrate by hot filament chemical vapor deposition in a gas mixture of hydrogen and methane. The chemical bonding states, surface texture, and electrical resistivity of these films were analyzed by X-ray photoelectron spectroscopy, scan electron microscope, and four-point probe method. It was found that boron dopants play an important role in the texture and chemical bonding states of the diamond films. An appropriate concentration of boron dopants (B/C ratio of 10 000 ppm) can simultaneously improve crystal quality and reduce resistivity of the diamond films. The minimum resistivity of diamond films reaches 1.12 × 10⁻² Ω cm, which is applicable as electrodes.     

Suppression of boron diffusion due to carbon during rapid thermal annealing of SiGe based device materials—some comments

The development of silicon-germanium alloys to extend the range of silicon high-frequency circuits has highlighted the need to understand diffusion mechanisms in this important material. To optimise performance, it is necessary to minimise the diffusion of dopants such as boron, in these very narrow width devices. This paper discusses recent progress in understanding the role of carbon doping in retarding boron diffusion. Much progress in understanding the diffusion mechanisms in silicon has been gained using selective defect injection, building on the discovery in 1972 that broadening of marker layers could monitor the injection of defects. The technique has now been used successfully in silicon-germanium alloys, and has shown that interstitial type defects are responsible for boron diffusion both in SiGe and in SiGe:C. The effects of carbon in retarding boron diffusion in as-grown structures, as well as ion-implanted structures, are discussed.     

固/液相等离子喷涂制备固体氧化物燃料电池复合电极

提出并研究以硅片为基体、采用固/液相等离子喷涂工艺制备固体氧化物燃料电池复合电极.固相送料方式喷涂阳极和阴极;悬浮液束流送料方式喷涂电解质.用CCD监测悬浮液束流与等离子射流形态,其特征分析结果表明最佳注射气压为0.25MPa.采用SEM和EDAX对电极涂层微观组织和组分进行分析,结果表明:喷涂距离是影响电解质涂层形貌...     

Thermal stability of undoped polycrystalline silicon layers on antimony and boron-doped substrates

The structure of as-deposited and annealed polycrystalline silicon layers has been investigated by scanning electron microscopy and x-ray diffraction. The structure of intentionally undoped layers prepared by low pressure chemical vapor deposition at a temperature of 640 °C was found to be stable upon annealing at temperatures lower than about 900 °C. On the other hand, primary recrystallization of the layers has been observed during annealing at temperatures in the range of 900 to 1150 °C. Isochronal annealing revealed the activation energy for the primary recrystallization of undoped layers as 0.6 eV. The activation energy for diffusion of silicon self-interstitials along the grain boundaries was calculated to be 2.2 eV. The difference in grain-growth process was observed for the undoped layers grown either (i) on lightly boron-doped substrate or (ii) on the substrate heavily doped with antimony. The different grain-growth mechanism was found to be a consequence of antimony diffusion into the polycrystalline layer.