Si基体上双层Ti－O薄膜的XPS和AES分析研究

采用沉积－离子轰击－沉积工艺制备了双层Ｔｉ－Ｏ薄膜，并利用ＸＰＳ和ＡＥＳ对膜层进行了深度分析．结果发现：在氩离子轰击后的薄膜上再沉积同质薄膜，在膜表层一定厚度内可得到具有化学配比的ＴｉＯ２薄膜；氩离子的轰击使钛及碳氧化物内迁入Ｓｉ基体，而Ｓｉ外迁到膜内，并造成多价形式的Ｔｉ氧化物共存，ＴｉＯ２在这些Ｔｉ氧化物中所占的比例随沉积膜深度呈现先逐渐减少而后又逐渐增大的分布规律；此外，氩离子的轰击使得薄膜与基体在界面处形成较宽的、复杂的混合层．混合层主要由ＴｉＯ２、Ｔｉ２Ｏ３、ＴｉＯ、未氧化完全的ＳｉＯ２－ｘ及纯Ｓｉ组成。     

Numerical Study on the Two-Dimensional Temperature Fields of Titanium/Aluminum Double-Layer Target Irradiated by High-Intensity Pulsed Ion Beam

Interaction between high-intensity pulsed ion beam (HIPIB) and a double-layer target with titanium film on top of aluminum substrate was simulated. The two-dimensional nonlinear thermal conduction equations, with the deposited energy in the target taken as source term, were derived and solved by finite differential method. As a result, the two-dimensional spatial and temporal evolution profiles of temperature were obtained for a titanium/aluminum double-layer target irradiated by a pulse of HIPIB. The effects of ion beam current density on the phase state of the target materials near the film and substrate interface were analyzed. Both titanium and aluminum were melted near the interface after a shot when the ion beam current density fell in the range of 100A/cm2 to 200A/cm2.     

Sensitizing Mechanism and Adsorption Properties of Dye—Sensitized TiO2 Thin Films

The dye-sensitized TiO2 complex films were prepared by the dye coat onto TiO2 surfaces,and the sensitizing mechanism and adsorption properties of the dye-sensitized TiO2 complex films were inverstigated.The influence of the application conditions of dye adsorbed on TiO2 films on the amount of dye adsorption was discussed.Experimental results show that the concentration,the temperature of dye solutions and the dipping time of TiO2 films in the dye solutions have a significant influence on the amount of dye adsorption.Cell test indicates that the conversion efficiency of light to electricity increases with the amount of dye adsorption.     

Analysis of counter ions of cyanine dye in Langmuir–Blodgett films by PIXE

Langmuir–Blodgett (LB) films of 1-methyl-1^′-octadecylquinocyanine bromide, iodide and perchlorate were prepared from subphases containing NaClO₄, KBr and/or KI. Each sample consists of an arachidic cadmium layer and about 100 cyanine dye layers on a Si substrate. Anions incorporated into the film as counter ions from the subphase were analyzed by particle induced X-ray emission (PIXE) using a 2.5 MeV He²⁺ beam. It was found that the dissociation of the cationic dye molecule in the monolayer at the air/water interface leads to the substitution of counter anions of the dye molecules, and the subsequent incorporation of the counter anions in the LB films. Some of the dissociation constants of cyanine halide dyes were estimated.     

用于同位素电池的储能复合电极的可行性研究

借鉴太阳能电池Ti/Pd/Ag复合电极的设计方案，将其优化设计为Ti/Pd/Au复合电极并加载氚源，以此验证同位素源与换能器件整合的可行性。在N型单晶硅基体上制备电极，为研究氚在电极中的行为，用氘气模拟氚气对电极进行同位素加载，采用XRD、SEM和四探针研究复合电极的储氚性能、微结构、电学性能等的变化。结果表明：复合电极能吸附氘并生成TiD_x（x≤2），具备一定的储氚性能；在Ti与Si界面处出现了TiSi₂相，表明膜基间发生了合金化，这提高了复合电极与硅基体的结合强度，同时降低了接触电阻；10^-4 Ω•cm量级的表面电阻率基本可满足对电极导电性能的要求。由此可见，Ti/Pd/Au复合电极应用于伏特效应同位素电池是可行的。     

Study of swift heavy ion irradiation effect on indium tin oxide coated electrode for the dye-sensitized solar cell application

Our long term objective is to study the swift heavy ion (SHI) irradiation effect on photoanode of dye-sensitized solar cell (DSSC) with the aim to investigate the stability of DSSC component in space irradiations and possibility of improvement in efficiency of DSSC due to ion induced effects in oxide layer. The DSSC photoanode consists of three layers viz; transparent conducting oxide (TCO), porous oxide with wide band gap and monolayer of dye molecule on top of corning glass substrate respectively. In the present study, procured radio frequency (RF) sputtered indium tin oxide (ITO) film on corning glass substrate were irradiated by SHI using 110 MeV Ni⁸⁺ ions at different fluences ranging from 3.0 × 10¹¹ ion/cm² to 1.0 × 10¹⁴ ion/cm². After irradiation significant changes have been observed in the structural, optical and electrical properties using X-ray diffraction (XRD), UV-Vis and Four Probe measurements, respectively. Overall there is 13% increase in optical transmittance which is favorable and moderate increase in sheet resistance from 8 Ω/□ to 18 Ω/□ which is still within acceptable limits for DSSC applications.     

高激光损伤阈值化学膜透射元件的研制

以K9和熔石英玻璃为基底结合溶胶-凝胶镀膜技术,制备了用于负载1 064 nm和355 nm激光辐射的高损伤阈值透射玻璃元件。综合考虑基底表面和亚表面质量及薄膜质量,系统分析了影响激光损伤阈值的因素,并通过基底加工与薄膜改性的结合大幅提高了元件的损伤阈值。在薄膜改性方面,采用溶胶内添加聚乙二醇和氨气氛处理相结合的方法,使薄膜的结构缺陷减少,孔径分布更合理,所得薄膜的抗激光损伤能力远大于未处理的基底的。在基底加工方面,采用超级抛光和化学腐蚀的方法获得了超光滑表面和低缺陷亚表面,使用于红外波段的K9玻璃和紫外波段的熔石英玻璃的激光损伤阈值分别提高到原来的1.3和4.1倍。将上述改性后的薄膜镀在改性后的基底上,所得透射元件的激光损伤阈值不小于相应基底的。     

Annealing behavior of ultrathin Mo layer located at interface or on surface of Ti－Si system

Annealing behavior,at different annealing temperatures,of an ultrathin Mo layer located between a Ti film and Si substrate or deposited on the top of surface of a Ti film was investigated by Rutherford backscattering spectrometry(RBS), cross-sectional transmission electron microscopy(TEM) and energy dispersive X-ray spectrometry(EDS),In a Ti/Mo/Si structure,partially reacted film with layer structure of Ti-rich silicide/TiSi2/(Mo,Ti) Si2 on a Si substrate was formed after 550℃ annealing for 30min.The ratio of Mo to Ti in(Mo,Ti)Si2 layer decreases from near Si substrate upwards and becomes zero at about 20nm away.In a Mo/Ti/Si structure, The surface Mo layer enhances the Si diffusion from the substrate during annealing.Mo bearing Ti rich silicide exists on the surface until 600℃ and then converts to (Mo,Ti )Si2 after 650℃ annealing,and the atomic ratio of Mo to Ti decreases from the top surface into Ti silicide film,and becomes zero at about 30nm away from the surface.In both cases of interface Mo and surface Mo layer,thd atomic ratio of Mo to Ti in the region of (Mo,Ti)Si2 was found to be very low,with an average value of less than 0.2.Low content of Mo in Mo containing ternary silicide leads easily to the formation of the stable phase of C54(Mo,Ti)Si2,which acts as a template for the formation of C54 TiSi2 beneath when Mo is deposited on the surface.     

单晶硅表面钝化层在低能电子辐照前后的SIMS和XPS分析

为了研究低能电子辐照对单晶硅器件表面钝化材料中产生的化学微结构的变化,在轻掺杂P型单晶硅基底上制作了三种表面钝化膜,分别是单一SiO₂钝化膜、SiO₂/Si₃N₄复合钝化膜、硼硅玻璃/Si₃N₄复合钝化膜,开展了表面钝化单晶硅在最大能量70 keV的加速器电子束下的辐照实验。样品在空气气氛下辐照6 h,用二次离子质谱（SIMS）测试了辐照前后三种表面钝化膜中Si、N、B的纵深变化,同时用Ar离子刻蚀X射线表面光电子能谱（XPS）对Si元素的化学结合状态进行测试分析。结果表明：对单一SiO₂钝化的轻掺杂P型材料,辐照在SiO₂/Si界面产生明显的材料结构变化,界面附近的SiO₂不再是完整化学计量比,而是SiO_x（x<2）;对SiO₂/Si₃N₄复合钝化的轻掺杂P型材料,辐照对SiO₂/Si₃N₄界面结构影响较小,主要的影响仍然在SiO₂/Si界面,SiO₂辐照分解后产生的游离O元素可扩散到SiO₂/Si₃N₄界面;辐照在硼硅玻璃/Si界面和硼硅玻璃/Si₃N₄界面引起的变化小于在SiO₂/Si界面和SiO₂/Si₃N₄界面的变化。研究表明低能电子辐照对单晶硅表面钝化层的化学微结构损伤主要存在于SiO₂/Si界面,该结构损伤并不能通过SiO2/Si₃N₄复合钝化得到明显改善,而采用硼硅玻璃/Si₃N₄复合钝化有助于增强单晶硅表面及钝化层各界面材料结构的稳定性。     

用于光电化学水分解的高光氢转换效率TiO2纳米棒阵列

半导体一维纳米材料具有独特的光电性质,且相对于零维纳米颗粒,具有良好的电子传输途径,因而在光电化学(PEC)分解水中有着重要的应用前景。TiO2纳米棒和纳米线已被证实具有优良的PEC性质。本文采用水热方法在氟掺杂二氧化锡导电玻璃(FTO)上制备了紧密规整的金红石型TiO2纳米棒阵列,研究了活化温度对TiO2纳米棒电极的光活性影响,并计算其光氢转换效率。该光氢转换效率高于同类报道的数据。     

RBS study of Ti/ZnO interface

We have studied the interface stability of the Ti(overlayer)/ZnO(substrate) system. Ti thin film was grown on the Zn face of single crystal ZnO(0 0 0 1) substrate by the vacuum deposition technique. The Ti film thickness was typically 16 nm. Then the samples were annealed in air at 300 and 400 °C for 15 min, respectively. The deposition and annealing effects on the interface structure were investigated with Rutherford backscattering and channeling spectroscopy using 2 MeV He⁺ ion beam. After Ti deposition the minimum yield from the ZnO substrate increased from 2% to 7%. This suggests severe damage caused by deposition, i.e. the interface reaction between Ti and ZnO (even at room temperature). A significant amount of Zn (approximately 6.4 × 10¹⁶ atoms/cm²) moved onto the surface after post-annealing at 400 °C. Since Ti has a stronger tendency to react with O than Zn, it is expected that Ti reacts with substrate oxygen leaving behind free Zn atoms, which can easily migrate onto the surface. We discuss how the Ti/ZnO interface reaction in detail, and seek to find another good metallic contact for ZnO devices, which are attracting much attention recently for practical applications as well as scientific aspects.     

水化学对Zr-4合金氧化膜形貌的影响

为了研究LiOH水溶液影响Zr-4合金耐腐蚀性能的机理,用扫描电子显微镜和扫描探针显微镜观察Zr-4合金样品在不同介质中腐蚀后氧化膜内外表面的形貌。实验结果表明：由于氧化过程体积膨胀,氧化膜中存在平行于界面的压应力。在压应力的作用下,氧化膜向外鼓起,并在垂直于平面的方向上产生张应力,导致氧化膜破裂,从而使腐蚀加速。LiOH水溶液浓度越高,这个过程越快。     

Study of Characteristics of the Radio-Frequency Sheath over a Substrate with a Circular Trench

Since processed substrates usually exhibit nonplanar surface structures in Micro-Electro-Mechanical-Systems (MEMS) etching, a two-dimensional (2D) fluid model is developed to simulate the characteristics of the sheath near a conductive substrate with a circular trench, which is placed in an argon discharge powered by a radio-frequency (rf) current source. The model consists of 2D time-dependent fluid equations, the Poisson equation, and a current balance equation that can self-consistently determine the instantaneous voltage on the substrate placed on a powered electrode. The effects of both the aspect ratio (depth/width) and the structure of the trench on the characteristics of the sheath are simulated. The time-averaged potential and electric field in the sheath are calculated and compared for different discharge parameters. The results show that the radial sheath profile is not uniform and always tends to adapt to the contour of the substrate, which is believed to be the moulding effect. Affected by the structure of the substrate surface, the potential and electric field near the inner and outer sidewalls of the trench exhibit obvious non-uniformity, which will inevitably lead to non-uniformity in etching, such as notching. Furthermore, with a fixed amplitude of the rf current source, the potential drops and the sheath thickness decrease with an increase in aspect ratio.     

The characteristics of primary and secondary arcs on a solar array in low earth orbit

In this paper, the characteristics of the primary arc and secondary arc on a solar array in low earth orbit(LEO) are investigated. The vacuum plasma environment in LEO has been used to study the primary arc and secondary arc of a high-voltage solar array. Silicon solar cells with rigid substrate specimens are used for the experiment. The series-parallel spacing of the silicon solar cells is 1 mm. The string currents of the solar cells are 0.7 A, 1.5 A and 2 A. The primary arc and secondary arc are photographed by high-speed cameras. The differences between the primary arc and secondary arc are observed. The secondary arc can be observed before the primary arc is extinguished. The primary arc is a single arc when the string current is 0.7 A. Multiple arc columns are accompanied by higher arc current. Two arc columns of the primary arc can be observed at 1.5 A string current and 2 A string current. The multiple primary arc columns are related to higher bias voltage. The threshold for sustained arcing is near 145 V/0.7 A, 105 V/1.5 A and 100 V/2 A at 1 mm string gap. Moreover, the transition time of secondary arc formation is analyzed, and found to be about 10–13 μs. The string currents, string voltages and primary arc have no effect on the transition time of the secondary arc formation.     

Surface Electromechanical Coupling on DLC Film with Conductive Atomic Force Microscope

Diamond-like carbon (DLC) film composed of microscopically insulation but microscopically a mixture of conducting (sp^2) and insulating (sp^3) phases was discussed on the local modification with a conductive atomic force microscope (C-AFM). Especially, a topographic change was observed when a direct current (DC) bias-voltage was applied to the DLC film. Experimental results show that a nanoscale pit on DLC surface was formed when applying a positive 25 V on DLC film. According to the interacting force between CoCr-coated microelectronic scanning probe (MESP) tip and DLC surface, as well as the Sondheimer oscillation theory, the “scalewing effect“ of the pit was explained. Electromechanical coupling on DLC film suggested that the depth of pits increased with an increase of load applied to surface when the cantilever-deflected signal was less than a certain threshold voltage.     

Track-etched nanopores in spin-coated polycarbonate films applied as sputtering mask

Thin polycarbonate films were spin-coated on silicon substrates and subsequently irradiated with 1-GeV U ions. The ion tracks in the polymer layer were chemically etched yielding nanopores of about 40 nm diameter. In a second process, the nanoporous polymer film acted as mask for structuring the Si substrate underneath. Sputtering with 5-keV Xe ions produced surface craters of depth ∼150 nm and diameter ∼80 nm. This arrangement can be used for the fabrication of track-based nanostructures with self-aligned apertures.     

电子束辐照制备Pd/TiO2光催化薄膜

用电子束辐照浸泡在浓度分别为1×10-5、1×10-4、1×10-3、1×10-2和1×10-1mol/L的PdCl2溶液中的TiO2薄膜,在TiO2薄膜表面形成Pd纳米颗粒.通过X射线衍射(X-ray diffractometry,XRD)、场发射扫描电镜(Field emission scanning electron microscope,FESEM)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)和紫外可见(Ultraviolet visible,UV-Vis)吸收光谱对辐照后的Pd/TiO2薄膜进行表征.分析表明,TiO2薄膜表面上沉积了直径20-50 nm的颗粒,为面心立方结晶的金属Pd;Pd/TiO2薄膜的UV-Vis光谱吸收边向可见光方向发生了偏移.用甲基橙作为光催化降解反应物,研究了Pd/TiO2薄膜分别在紫外光、可见光作用下的光催化降解效率.结果表明,Pd/TiO2薄膜的光催化能力显著地提高,在紫外光、可见光作用下的光催化效率分别提高了2.25倍和3.4倍.     

电沉积法制备镍-63放射源工艺研究

微型核电池用镍-63放射源要求放射源表面发射率高、镀层薄、衬底小,以小体积、高比活度、低镍浓度的镍-63溶液作为电沉积液,建立一种直流恒流电沉积制备镍-63放射源的方法。采用该方法,衬底为紫铜材质、Ni²⁺浓度为1 g/L、电沉积液pH为3.5～4.5、氨基磺酸浓度为0.1 g/L条件下电沉积1 h,电沉积率可达95.8%。制备的镍-63放射源源片镀层紧密、光亮,厚度0.3~1.6 μm,其表面发射率最高可达2.40×10⁷ s^-1·(2πSr)^-1,活度最高可达1.89×10⁹ Bq,满足微型核电池的应用需求。同时,通过对剩余电沉积液进行回收、组分调节,实现了电沉积液的重复利用,减少了镍-63原料的浪费。     

Physical Properties of Titanium Oxide Thin Films Prepared by DC Magnetron Sputtering: Influence Substrate Temperature and O2/Ar in the Gas Mixture

Titanium oxide thin film compounds were grown on p-type Si (100) and BK7 glass as substrate using reactive DC magnetron sputtering. The effect of temperature growth on structural, optical and morphological properties was investigated. By means of X-ray diffraction (XRD) the phase composition was characterized. UV–Vis-NIR spectroscopy was used for reflection and transmission measurements of deposited thin film layers. Atomic force microscopy was used to evaluate and compute the surface roughness changes for different temperatures growth. The XRD results show that the temperature growth effects on the phase formation and structure. Increasing the substrate growth temperature would result in change of film thickness due to different phase and structure formation. The calculated band gap from optical measurements of the thin films shows a decrease at higher substrate temperature growth.     

Synthesis of Cu-Doped Mixed-Phase TiO2 with the Assistance of Ionic Liquid by Atmospheric-Pressure Cold Plasma

An atmospheric-pressure dielectric barrier discharge(DBD) gas-liquid cold plasma was employed to synthesize Cu-doped TiO_2 nanoparticles in an aqueous solution with the assistance of[C_2MIM]BF_4 ionic liquid(IL) and using air as the working gas.The influences of the discharge voltage,IL and the amount of copper nitrite were investigated.X-ray diffraction,N_2adsorption-desorption measurements and UV-Vis spectroscopy were adopted to characterize the samples.The results showed that the specific surface area of TiO_2 was promoted with Cu-doping(from 57.6 m~2·g~(-1) to 106.2 m~2·g~(-1) with 3%Cu-doping),and the content of anatase was increased.Besides,the band gap energy of TiO_2 with Cu-doping decreased according to the UV-Vis spectroscopy test.The 3%Cu-IL-TiO_2 samples showed the highest efficiency in degrading methylene blue(MB) dye solutions under simulated sunlight with an apparent rate constant of 0.0223 min~(-1),which was 1.2 times higher than that of non-doped samples.According to the characterization results,the reasons for the high photocatalytic activity were discussed.