氢致LaMg2Ni合金薄膜的光电性能变化

采用电子束蒸发法沉积LaNi/Mg多层膜,再于350℃真空退火合金化的方法制备了厚度为375nm的LaMg2Ni合金薄膜.在吸、放氢过程中,该合金薄膜能够在高反射的金属态和透明的半导体态之间可逆地转变.在可见光波长范围内的平均透射率和电阻率在反射态和透明态之间的对比度大于104.利用扫描电子显微镜和原子力显微镜观察了吸放氢前后薄膜的表面及剖面形貌.结果表明,在氢化过程中薄膜表面的平整性降低且不可恢复,是脱氢态中出现低反射现象的主要原因.     

非晶Ni88P12合金薄膜的表面形貌特征与晶化行为的研究

采用化学镀的方法在363K和p型Si（100）衬底上制得非晶Ni₈₈P₁₂合金薄膜．利用X射线衍射、X射线光电子能谱、扫描隧道显微镜和原子力显微镜对非晶合金薄膜及其经处理后形成的氧化态、还原态和晶态的结构、组分和表面的形貌特征作了研究，并对它的晶化行为作了初步探讨．结果表明，非晶合金薄膜是由纳米级微粒聚集成微米级颗粒组成；在低于晶化温度条件下经氧化和还原处理后的薄膜表面晶化；在晶化过程中，合金薄膜的非晶纳米微粒转变为微晶后长大成晶粒，其表面结构光滑平坦，几何边界 关键词：     

溶胶-凝胶法制备ZnO薄膜的成核-生长和失稳分解研究

采用溶胶-凝胶法在ZnWO₄单晶上制备出透明的ZnO薄膜.通过光学显微镜观察了Z nO薄膜的表面形貌.实验结果表明，ZnO薄膜的形成经历了表面成核，晶粒长大和岛的形成三 个不同的阶段.由于ZnO晶核是在非平衡条件下生长的，在生长过程中不可避免地出现了枝晶 生长和分形生长以及失稳分解. 关键词： 氧化锌薄膜 成核 枝晶生长 分形生长 失稳分解     

H2 气对脉冲磁控溅射铝掺杂氧化锌薄膜性能的影响

实验采用脉冲磁控溅射法制备铝掺杂氧化锌(AZO)薄膜.为了进一步提高AZO薄膜的光电性能,在溅射过程中加入一定流量的氢气,以高纯ZnO ∶Al₂O₃陶瓷靶为溅射靶材,制备AZO/H透明导电薄膜.通过测试薄膜的结构特性、表面形貌及其光电性能,详细地研究了氢气流量对AZO薄膜性能的影响.溅射过程中引入氢气,可以促进薄膜的晶化,提高薄膜的迁移率和透过率(400—1100 nm).采用纯氩气溅射制备AZO薄膜的电阻率为5.664×10^-4 Ω·cm 关键词： 氧化锌 氢气流量 磁控溅射 太阳电池     

Al掺杂对合金Mg1-xTix及其氢化物稳定性的影响

用密度泛函理论,研究了Al对合金Mg_1-xTi_x及其氢化物稳定性和电子结构的影响. 通过计算不同掺杂浓度的Mg-Ti-Al合金的形成焓,发现当Al和Ti的浓度之比为1:1时, 合金结构最稳定,有利于氢的可逆吸收;而掺杂体系的氢化物稳定性降低, 可提高放氢性能.通过对态密度,电子密度和键长的分析, 表明Al改善Mg-Ti系统的放氢性能的原因是掺杂后减少了低能级区成键态的电子以及减弱了Mg-H, Ti-H原子间的相互作用. 关键词： 1-xTi_xH₂储氢材料')" href="#">Mg_1-xTi_xH₂储氢材料 赝势平面波 电子结构 稳定性     

氢、氧终端掺硼金刚石薄膜的电子结构

利用氢微波等离子体溅射和浓酸中沸煮方法分别制备了氢、氧终端掺硼金刚石薄膜.借助X射线光电子能谱及接触角检测对两种终端薄膜表面进行了分析,通过扫描探针显微镜研究了针尖和样品间的扫描隧道谱.结果表明,氢终端掺硼金刚石表面能带向上弯曲,在高于价带顶位置存在浅受主能级;氧终端表面能带向下弯曲,带隙较宽,带隙中不存在表面态.对两种终端金刚石薄膜的导电机理进行了讨论. 关键词： 氢终端 氧终端 掺硼金刚石薄膜 电子结构     

蓝宝石基片的处理方法对ZnO薄膜生长行为的影响

采用反应射频磁控溅射方法,在经过不同方法处理的蓝宝石基片上,在同一条件下沉积了ZnO薄膜.利用原子力显微镜、X射线衍射、反射式高能电子衍射等分析技术,对基片和薄膜的结构、表面形貌进行了系统表征.研究结果显示,不同退火条件下的蓝宝石基片表面结构之间没有本质的差异,均为α-Al₂O₃ (001)晶面,但基片表面形貌的变化较大.在不同方法处理的蓝宝石基片上生长的ZnO薄膜均具有高c轴取向的织构特征,但薄膜的表面形貌差异较大.基片经真空退火处 关键词： ZnO薄膜 反应磁控溅射 基片处理 形貌分析     

透明薄膜的干涉相干峰分离算法

白光干涉技术具有高度唯一性,广泛地被使用在三维表面形貌和台阶高度的测量。但是测量透明薄膜时,薄膜表面和基面都有光线反射与参考光线交汇,在被测表面的同一个位置不同高度两次产生干涉条纹,其干涉相干图中出现两个峰值。通过分析透明薄膜产生的干涉相干图的特点,提出了两种算法用来分离不同表面产生的干涉条纹。理论分析和试验结果表明,利用垂直扫描白光干涉法测量透明薄膜,由峰值分离算法和定位算法分别提取薄膜的上下表面,能够得到透明薄膜的高精度三维形貌和厚度信息。     

脉冲偏压电弧离子镀TiO2薄膜的力学与光学性能

用脉冲偏压电弧离子镀技术在玻璃基片上制备均匀透明的TiO₂薄膜.利用X射线衍射仪、原子力显微镜、扫描电子显微镜、紫外-可见透射光谱仪和纳米压痕仪等手段,对不同脉冲负偏压下合成薄膜的相结构、微观结构、表面形貌、力学和光学性能进行表征.结果表明，沉积态薄膜为非晶态.脉冲负偏压对薄膜性能有明显的影响.随偏压的增加，薄膜厚度、硬度和弹性模量均先增大后减小，前者峰值出现在100—200 V负偏压范围，后两者则在250—350V范围.300 V负偏压时薄膜硬度最高，薄膜达到原子级表面光滑度，均方 关键词： 2薄膜')" href="#">TiO₂薄膜 脉冲偏压电弧离子镀 硬度 折射率     

微晶硅薄膜的表面粗糙度及其生长机制的X射线掠角反射研究

采用等离子体增强化学气相沉积技术沉积一系列处于不同生长阶段的微晶硅薄膜.通过同步辐射X射线掠角反射技术研究微晶硅薄膜的表面粗糙度随时间等的演化，探讨微晶硅薄膜的生长动力学过程及其生长机制.研究结果表明，在衬底温度为200 ℃，电极间距为2 cm，沉积气压为6.66×1０² Pa，射频功率密度为0.22 W/cm²，氢稀释度分别为99%和98%的沉积条件下，在玻璃衬底上生长的微晶硅薄膜生长指数β分别为0.21±0.01和0.24±0.01.根据KPZ模型，微晶硅薄膜的生长机制为有限扩散生长. 关键词： X射线掠角反射 微晶硅薄膜 表面粗糙度 生长机制     

三元合金Cu76Ni15Sn9的离子溅射研究

在２７ｋｅＶ Ａｒ⁺离子轰击时,用收集膜技术结合俄歇谱仪（ＡＥＳ）,研究了三元合金Cu₇₆Ni₁₅Sn₉系统的择优溅射行为。同时使用扫描电子显微镜（ＳＥＭ）与电子探针微分析（ＥＰＭＡ）．观察了靶点表面形貌变化并测定了形貌特征微区的合金组份原子的相对百分浓度。结果表明,Ｃｕ原子较Ｎｉ原子、Ｎｉ原子较Ｓｎ原子,在所测定范围（０─６０°）内择优发射。最后讨论了靶点表面形貌特征和“元素局域富集”现象对择优溅射过程的影响。 关键词：     

Microstructure, hydrogenation and optical behavior of Mg-Ni multilayer films deposited by magnetron sputtering

Mg-Ni multilayer films with sequential Mg and Ni layers were prepared by direct current magnetron sputtering. The substrate temperature influences the microstructure of the films greatly. The film deposited at 298 K exhibits multilayered structure, while the film shows nanocrystalline/amorphous composite structure at the deposition temperature of 473 K. The optical properties between hydrogenation/dehydrogenation states of the films were performed using spectrophotometer in visible light region. The film deposited at 473 K can switch from mirror-like metallic state towards brownish yellow transparent state under 0.6 MPa H₂ at 298 K, and the optical transmittance modulation reaches up to 20% both at a wavelength of 770 nm and IR region, while the film deposited at 298 K exhibits low optical change, and the optical switching behavior can hardly be found. The extra free energy stored in the boundary of the nanocrystallines benefits the formation of magnesium-based hydride, resulting in the enhancement of the optical switching properties of the Mg-Ni film deposited at 473 K.     

Novel and low reflective silicon surface fabricated by Ni-assisted electroless etching and coated with atomic layer deposited Al2O3 film

In this paper, nickel nanoparticles (Ni NPs) were deposited on planar silicon and pyramidal silicon wafers by the magnetron sputtering method, and then these Ni NP-covered samples were etched in a hydrofluoric acid, hydrogen peroxide, and deionized water mixed solution at room temperature to fabricate a low reflective silicon surface. An alumina (Al₂O₃) film was then deposited on the surface of the as-etched pyramidal sample by atomic layer deposition to further reduce the reflectance. The morphologies and compositions of these samples were studied by using a field emission scanning electron microscope attached to an energy-dispersive X-ray spectrometer. The surface reflectance measurements were carried out with a UV-Vis-NIR spectrophotometer in a wavelength range of 200–1100 nm. The SEM images show that the as-etched planar and pyramidal silicon samples were covered with many rhombic nanostructures and that some nanostructures on the planar silicon surface were ready to exhibit a flower-like burst. The reflectances of the as-etched planar and pyramidal silicon samples were 5.22 % and 3.21 % in the wavelength range of 400–800 nm, respectively. After being coated with a 75-nm-thick Al₂O₃ film, the etched pyramidal silicon sample showed an even lower reflectance of 2.37 % from 400 nm to 800 nm.     

Propagation distances of surface electromagnetic waves on Ni,Pd, Pt,and W metal surfaces

The propagation distances, L_x, of surface electromagnetic waves (SEW) on Ni, Pd, Pt, and W were measured using the two-prism coupling technique at wavelengths from 9.3 to 10.6 microm. Metal samples consisted of films, deposited on glass substrates by electron beam deposition, and metal foils. The measured L_x values for the Pd and Pt firms and Pt foil agree to within 20% of the calculated values from the two-media dispersion relation. The measured values of the propagation distance for the Ni film and foil and the W foil agree to within 50% of the calculated L_x. Scanning electron microscope (SEM) photographs and Auger analysis indicate that film imperfections and foil surface roughness contributed to the lower propagation distances observed for Pt and Pd while imperfections, roughness, and oxidation contributed to the disagreement between measured and calculated propagation distance for Ni and W.     

Elemental and phase composition analysis of hydrogen-sensitive Pd/Mg–Ni films

A magnesium–nickel (Mg–Ni) film with a palladium (Pd) overcoat is switchable between a conducting metallic state and a semiconducting state through hydridation and dehydridation processes. The Pd overcoat is added to suppress possible oxidation of the alloy layer. However, some Pd and oxygen (O) atoms are still able to diffuse into the alloy layer, such that the distributions of elemental and phase compositions along the direction of depth are quite complicated. In this work, we propose a method to obtain more detailed information on the elemental and phase compositions in a Pd/Mg–Ni film by means of analyzing Pd 3d_5/2, Pd 3p_3/2, Ni 2p_3/2, Mg 1s and O 1s photoelectron spectra. The method was applied to analyze a typical Pd/Mg–Ni film sample. Results verified that Pd can diffuse into the alloy layer. An Mg–O phase is formed near the surface. An Mg–Ni alloy phase dominates at deeper regions. The Mg–Ni phase contains 80% of the total number of atoms in the film, and is non-stoichiometric and highly disordered. Nevertheless, it can give a remarkable change of electrical resistivity during hydridation–dehydridation processes. PACS 79.60.-i; 61.05.C-; 79.60.Ht     

The effect of polymer coatings on switching behavior and cycling durability of Pd/Mg-Ni thin films

Although Pd-capped Mg-Ni alloy switchable mirror thin films have potential applications in smart windows and optical switches, they degrade quickly and cannot be switched after about 150 cycles. This must be improved for practical use. In this study, we tested several polymer coatings on the surface of Pd/Mg₄Ni switchable mirror thin films as a protective membrane and evaluated the optical switching property and durability. The polymer membrane is able to suppress the oxidization of Mg because it has an excellent gas separation characteristic. Polymer coating extended the switching durability of samples to about 1000 cycles. In addition, the transmittance of the thin film in the transparent state is improved by the coating.     

Microstructure and mechanical properties of a large-dimensional bulk nanocrystalline-based Fe–Al–Cr alloy prepared by an aluminothermic reaction casting and followed annealing at 1000 °C

A large-dimensional bulk nanocrystalline phase-based Fe–Al–Cr alloy with 10?wt.% Cr, which was about 200?mm in diameter and 10?mm in thickness, was prepared by an aluminothermic reaction casting and followed annealing at 1000?°C. Microstructures of the alloy were investigated by optical microscope, electron probe microscope, scanning electron microscope attached with electron backscattered diffraction, X-ray diffraction and transmission electron microscope. The magnetization curves of the alloy were tested by Lake Shore 7410 vibrating sample magnetometer. Compressive properties of the alloy were tested. The results show the alloy was consisted of a Fe–Al–Cr nanocrystalline matrix, Cr₇C₃ phase and contaminants in micrometre. Average grain size of the nanocrystalline matrix was 19?nm. Volume fraction of the Cr₇C₃ phase in the alloy was about 4.5%. After annealing, the saturated intensity of magnetization and the specific magnetic susceptibility of the alloy increased slightly from 99 emu/g and 0.083 emu/g?Oe to 104 emu/g and 0.113 emu/g?Oe, respectively. Compressive strength of the alloy was 1200?MPa and much higher than that of the small-scale nanocrystalline alloy and alloy with grains in micrometre.     

Epitactic growth of a decagonal phase in an Al–Ni–Co alloy film deposited on a (0001) sapphire substrate

Thin films of Al–Ni–Co alloy with an average thickness of 15?nm were produced by means of conventional vacuum deposition technique on (0001) sapphire substrates heated at various test temperatures. The microstructures and textures of the films obtained were thoroughly investigated by atomic force microscopy, X-ray diffraction and transmission electron diffraction and imaging techniques. The diffraction measurements have evidenced that the vacuum deposition of Al₇₂Ni₁₅Co₁₃ alloy on the substrates heated above 400°C allows a homogeneous poly-quasicrystalline film, consisting of the Ni-rich basic decagonal phase to grow. It has been further indicated by in-plane XRD analysis that the film deposited at 550°C contains a considerable amount of the decagonal grains epitaxially grown on the sapphire substrate. Possible epitaxial relations occurring between the deposit and the substrate will be detailed on the basis of results obtained from electron diffraction measurements.     

Cu<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Ni<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript> alloy nanoparticles embedded SiO<Subscript>2</Subscript> films: synthesis and structure

Cu–Ni fcc alloy nanoparticles (NPs) of tunable atomic ratios were generated in SiO₂ films. The films were prepared using the Cu(NO₃)₂ and Ni(NO₃)₂ co-doped inorganic–organic hybrid silica sols by single dipping. Transparent, crack-free, glassy SiO₂ films of 310 ± 10 nm in thickness embedded with high mol percent of Cu–Ni alloy NPs were yielded after annealing at 750 °C in 10% H₂-90% Ar atmosphere. Nominal compositions of the films were 20 mol% (Cu–Ni)-80 mol% SiO₂. Optical spectral study of the heat-treated films showed disappearance of Cu plasmon bands due to Cu–Ni alloy formation. Grazing incidence X-ray diffraction (GIXRD) studies revealed the formation of Cu–Ni alloy (2:1, 1:1 and 1:2) NPs inside the SiO₂ film. GIXRD showed a systematic shifting of the diffraction peaks with respect to the fcc Cu–Ni alloy composition, maintaining the nominal ratios. Transmission electron microscopy (TEM) studies of the representative Cu_0.5Ni_0.5-doped film showed existence of homogeneously dispersed Cu–Ni alloy NPs of average size 6.35 nm inside the SiO₂ matrix. The energy dispersive X-ray scattering (EDX) analysis of the individual NPs using the nano-probe (scanning TEM mode) confirmed the presence of both the Cu and Ni with the desired atomic ratio.