红外激光在线烧结EHD打印多层微米导电薄膜的性能实验研究

以相片纸为基底,以自制的纳米银导电墨水为介质,通过EHD电流体动力学设备制备出1～4层不同打印厚度的导电薄膜。采用激光烧结的方式对不同薄膜厚度的薄膜图案进行固化;用电阻表测量出固化后各厚度的导电薄膜的电阻率;采用扫描电子显微镜观察烧结前后不同层厚导电薄膜的表面形貌。结果表明：不同厚度薄膜图案烧结后的电阻率、表面形貌、薄膜表面孔隙率存在较大差异;3层厚导电薄膜的电阻率为2.9μΩ·cm,与块状银的电阻率接近,其导电薄膜表面形貌均匀,且孔隙率仅为7.9%,整体效果明显优于1、2和4层薄膜。通过研究给出薄膜制备相应的印刷层数以及不同厚度导电薄膜对应的最佳烧结参数,为纳米银导电薄膜的制备提供参考。     

本底真空对磁控溅射镍铬合金薄膜电阻的影响

目的研究本底真空对溅射镍铬合金薄膜性能的影响。方法在不同溅射时间下制备了不同厚度的镍铬合金薄膜,采用4、6、8、10 h不同的抽真空时间制备薄膜样品,并在空气、氮气及真空气氛中,对同一工艺条件下制备的镍铬合金薄膜样品分别在300、400、500℃下进行热处理,所有样品分别测试方块电阻。结果不同厚度的镍铬合金薄膜的方块电阻与薄膜厚度之间存在非线性关系,样品的方块电阻随着溅射前抽真空时间的增加而降低。在真空和空气中进行热处理的薄膜的方块电阻变化规律一致,而在氮气中的则相反。结论本底真空残留气体对镍铬合金薄膜的氧化是引起薄膜电阻率增大的主要原因,即射频磁控溅射镍铬合金薄膜被氧化而使电阻率增大,随着溅射时间的增加,残留气体影响减小,导致电阻率降低。前期抽真空时间大于9 h,靶材溅射清洗时间大于110 min时,制备的镍铬合金薄膜电阻率才趋于稳定。     

射频磁控溅射沉积ITO薄膜性能及导电机理

将In2O3和SnO2粉末按质量比1：1热压烧结制成靶材，采用射频磁控溅射制备了高性能的ITO薄膜。实验结果表明：氩气压强对薄膜的电阻率、可见光透射率TVITL有着重要的影响，其最佳值为0．2Pa。ITO膜的方阻、TVIL和颜色与膜厚有着密切的关系。提高基体温度ts可以改善薄膜的性能，在ts为200℃时，ITO薄膜的1k达到90％以上（含玻璃基体），方阻为13．1Ω／□。根据薄膜生长的3个阶段理论，建立了薄膜厚度与电阻率的关系：在ITO薄膜生长过程中，依次出现热发射和隧道效应、逾漏机制以及Cottey模型导电机理。由实验结果求得了临界厚度吐约为48-54nm，AFM表征结果进一步表明ITO薄膜随着厚度增加表现出不同的导电机理和尺寸效应。     

ZnO:Si透明导电薄膜厚度对其光电性能的影响

目的研究ZnO∶Si薄膜厚度对其生长速率、结晶度、光透率和电阻率的影响。方法用直流磁控溅射系统在玻璃基片上沉积不同的时间,获得5个厚度不同的ZnO∶Si薄膜样品,对比研究了其薄膜生长取向和结构特性、微观形貌、电学参数及透过率曲线。结果 5个ZnO∶Si薄膜样品都为多晶膜,具有单一的(002)衍射峰,沿垂直于基片的c轴方向择优生长。当薄膜厚度从207.6 nm增加到436.1 nm时,薄膜的晶粒尺寸增大,晶化程度提高,电阻率变小;膜厚增至497.8 nm时,薄膜的晶化程度反而降低,电阻率增加。在可见光范围内,5个薄膜样品的平均透过率都高于91.7%。结论膜厚对ZnO∶Si薄膜的电学性能有较大影响,对光学性能的影响则较小。     

氧化铟锡(ITO)薄膜溅射生长及光电性能调控

目的 选取影响氧化铟锡(ITO)薄膜生长关键的3种参数,即薄膜生长的氧气流量、薄膜厚度和热处理退火,系统研究其对ITO薄膜光学和电学性能的影响规律。方法 采用直流溅射法,在氩气和氧气混合气氛中溅射陶瓷靶材制备ITO薄膜样品。利用真空热处理技术对所制备的ITO薄膜进行真空退火处理。通过表面轮廓仪测试厚度、X-射线衍射仪(XRD)表征结构、X-射线光电子能谱仪(XPS)分析元素含量、分光光度计测试透过率和四探针测试薄膜方块电阻,分别评价薄膜厚度、光学性能和电学性能,并对比研究热处理对薄膜结构和光电性能的影响规律。结果 电阻率随氧气流量的增加呈现出先缓慢后急剧升高的规律,在氩气和氧气流量比为150∶8时,可得到400 nm厚、电阻率为8.0×10^?4 ?.cm的ITO薄膜。厚度增加可降低薄膜电阻率,氧气流量的增加可明显改善薄膜透光性。通过真空热处理可提高室温沉积ITO薄膜的结晶性能,较大程度地降低电阻率。在真空热处理条件下增大薄膜厚度可降低薄膜电阻率,氧气流量增加不利于ITO薄膜电阻率的降低。在氩气和氧气流量为150∶6条件下制备的ITO薄膜,经500 ℃真空热处理后电阻率可达到最低值(2.7×10^?4 ?.cm)。结论 通过调控氧气流量和厚度来优化ITO薄膜的结构和氧空位含量,低温下利用磁控溅射法可制备光电性能优异的ITO薄膜;真空热处理可提高薄膜结晶性能,通过氧气流量、厚度和热处理温度3种参数调控可获得最低电阻率的晶态ITO薄膜(2.7×10^?4 ?.cm),满足科技和工程领域的需求。     

退火温度对磁控溅射Mo薄膜结构和性能的影响

采用磁控溅射技术在石英基体上制备了厚度为600 nm的Mo薄膜,并在不同温度下(400～ 900℃)对其进行退火处理.通过XRD、SEM、四探针测试仪对Mo薄膜的结构和性能进行了分析.结果表明,随着退火温度的升高,(110)晶面择优取向特性增强.Mo薄膜在退火温度为800℃时电阻率达到最小值3.56×10-5 Ω·cm,在900℃退火时薄膜出现宽度约为50 nm的微裂纹且薄膜电阻率较大.     

Co和Cu薄膜电学特性和连续性特征的判据

采用离子束溅射沉积了不同厚度的Co膜和Cu膜,利用四电极法测量了薄膜的电阻率,从而得到了Co膜和Cu膜的电导率随薄膜厚度的变化关系。实验结果表明,Co膜和Cu膜的电学特性都具有明显的尺寸效应。比较了同时考虑表面散射和晶界散射的电导理论得到的电导率公式与实验结果,不同薄膜厚度电导率的理论结果与实验结果符合较好。提出了厚度作为金属薄膜生长从不连续膜进入连续膜的一个特征判据,并利用原子力显微镜(AFM)观测了膜厚在特征厚度附近的Co膜和Cu膜的表面形貌。     

热处理条件对溶胶-凝胶法制备多孔TiO2薄膜微观结构的影响

以钛酸异丁酯为先驱物,乙二醇甲醚为溶剂,羟基纤维素(HPC)为添加剂,用溶胶-凝胶法制备了厚度在270 nm～420 nm的多孔TiO2薄膜.重点研究了薄膜微观形貌与热处理时间的关系,并对薄膜的截面电阻率进行了研究.在二次热处理温度550℃下处理60 min下得到多孔、厚度最大,截面电阻率最小的TiO2薄膜.     

辅助气体CH4和Ar对IBED制备碳膜性能的影响

采用离子束辅助沉积技术(IBED)制备了一系列碳膜,重点分析辅助气体CH4、Ar对碳膜组成相、电阻率、厚度和硬度的影响.结果表明:采用CH4辅助轰击制得的薄膜厚度高于采用Ar辅助轰击的薄膜厚度;采用Ar辅助轰击的薄膜在硬度、结合强度方面要优于CH4辅助轰击的薄膜;相对于类金钢石薄膜,所制备的碳膜更接近于类石墨膜.     

低温沉积ITO薄膜划擦行为、微结构、电学和光学性能的研究（英文）

通过RF磁控溅射技术制备不同溅射气压下的ITO薄膜,对其电阻率、光学透过率、XRD图、AFM图和划擦行为进行了研究。薄膜和基板的附着力通过划擦测试进行表征,重点研究了薄膜划擦测试的不同阶段的特征。研究表明随着Ar溅射气压的下降,薄膜附着力下降。而且,ITO薄膜的表面形貌和电阻率强烈的依赖于Ar气压。低温沉积ITO薄膜均为非晶态,在溅射气压0.8 Pa时得到电阻率(1.25×10~(-3)Ω·cm)和高可见光透过率薄膜(90%)。研究结果表明该薄膜光学禁带约为3.85 eV,电阻率主要受载流子浓度控制,受溅射气压的变化影响有限。     

超薄金属膜的电导特性

在Ｆ－Ｓ理论的基础上,考虑表面和晶界的散射,给出了超薄金属膜的电导率与厚度的关系式,与超薄铝膜的电导率随厚度变化的实验结果对比表明,计算曲线与实验曲线符合得较好。     

Evaluation of dispersion state and thermal conductivity measurement of carbon nanotubes/UV-curable resin nanocomposites

We describe (i) the evaluation of bundled degrees of single-walled carbon nanotubes (SWNTs) in SWNT/UV-curable resin composite films based on the intensity change in the radial breading mode (RBM) of their Raman spectra at a 785-nm excitation, and (ii) the thermal conductivity measurements of the composites films using the temperature wave analysis method. The homogeneous dispersion of the SWNTs produced a gradual increase in the thermal conductivity with an increase in the SWNT loading up to 5.0 wt%. This observed behavior is quite different from that of the electric conductivity of the composite films, in which the electric conductivities dramatically decrease at around only a 0.05 wt%-SWNT loading as previously reported.     

Metallic Glass Nano-composite Thin Films for High-performance Functional Applications

Metallic glass nanocomposite thin films were synthesized for an immiscible Ag-Cu alloy system by magnetron sputtering. The structure of the films was unique, consisting of homogeneously dispersed nanocrystallites in an amorphous matrix. The size and volume fraction of the nanocrystallites increased with increasing film thickness resulting in increased elastic modulus and hardness. The high electrical conductivity of the nanocomposite films was examined by a valence-band study, which showed that exchange interaction between Ag and Cu in the nanocomposite structure resulted in enhanced charge carrier concentration. The inverse correlation between electrical conductivity and film thickness was explained by surface and interface scattering of electrons with increasing volume fraction of nanocrystallites. The small temperature dependence of conductivity was attributed to the distorted Fermi surface of the nanocomposite films resulting in a greater contribution from structure scattering, which is temperature-independent.     

Influence of Nitrogen Vacancy Concentration on Mechanical and Electrical Properties of Rocksalt Zirconium Nitride Films

To study the influence of the nitrogen vacancy(V_N)on mechanical and electrical properties of zirconium nitride deeply,Zr N_x films with different V_N concentrations were synthesized on the Si(111)substrates by enhanced magnetic filtering arc ion plating.The morphologies,microstructures,residual stresses,compositions,chemical states,mechanical and electrical properties of the as-deposited films were characterized by field-emission scanning electron microscopy,X-ray diffraction,X-ray photoelectron spectrometry,Nanoindenter and Hall effect measurements.The results showed that Zr N_x films exhibited rocksalt single-phase structure within a V_N concentration ranging from 26 to 5%.The preferred orientation,thickness,grain size and residual stress of the Zr N_x films kept constant at different V_N concentrations.Both the nanohardness and elastic modulus first increased and then decreased with the decrease in V_N concentration,reaching the peaks around 16%.And the electric conductivity of the Zr N_x films showed a similar tendency with nanohardness.The underlying atomic-scale mechanisms of V_N concentration-dependent hardness and electric conductivity enhancements were discussed and attributed to the different electronic band structures,rather than conventional meso-scale factors,such as preferred orientation,grain size and residual stress.     

The electric and thermoelectric properties of CuInSe2-based chalcopyrite

It has been found that CuInSe₂ chalcopyrite is an extrinsic semiconductor that exhibits a more complex temperature dependence of its electric conductivity than conventional extrinsic semiconductors. This temperature dependence of the electric conductivity results from the complex structure of the electron energy spectrum in these crystals. The temperature dependence of the electric conductivity has been used to determine the activation energies of the energy levels of the intrinsic defects that are formed upon the violation of the stoichiometry of the CuInSe₂ structure. The analysis of the temperature dependence of the thermoelectric power has revealed that the main scattering mechanism at high temperatures is acoustic-phonon scattering.     

MICROSTRUCTURE AND PROPERTIES OF ANNEALED ZnO THIN FILMS DEPOSITED BY MAGNETRON SPUTTERING

1.IntroductionZnO especially in the form ofthin film shasbeen attracting attention because ofits m any applica-tions,such astransparentelectrodes,varistors,phosphors,gassensors,surface acousticw ave devicesandpiezoelectric actuators[1,2].M ore recently,re…     

Influence of phonon focusing on the Knudsen flow of phonon gas in single-crystal nanofilms of spintronic materials

Influence of the anisotropy of elastic energy on the phonon transport has been investigated in single- crystal nanofilms of Fe, Cu, MgO, InSb, and GaAs materials used for spintronic instruments and devices in the Knudsen flow regime of phonon gas. The dependences of the lattice thermal conductivity and lengths of free paths of phonons for all acoustic modes on the geometric parameters of the films have been considered for low temperatures with the dominance of the diffuse scattering of phonons at the boundaries. Physical aspects of the propagation of phonon modes in the films have been analyzed. It has been shown that the anisotropy of phonon transport in single-crystal films is due to the features of the propagation of phonon modes in elastically anisotropic films with a different relationship of the geometric parameters. The directions of heat flow and orientations of the film planes that yield the maximum and minimum thermal conductivity of phonons in film planes have been determined.     

Correlation between the chemical composition and the conduction mechanism of barium strontium titanate thin films

Sol-gel barium strontium titanate thin films with different barium-to-strontium (Ba:Sr) values have been fabricated as MFM configurations. The Perovskite phase for the films is confirmed via XRD. In order to correlate the effect of the chemical composition of the films with the conduction mechanism, different AC electrical parameters have been addressed. The results show that the impedance and dielectric constant decrease as Ba content in the film increases, whereas the conductivity shows the opposite variation; this is attributed to the grain size and dipole dynamics. Complex impedance (Z*) and electric modulus (M*) planes show three overlapping regions as the response for the bulk, the grain boundaries and the film/electrode interface mechanisms. These mechanisms have been represented by an equivalent circuit. The imaginary component of electric modulus (M″) versus frequency plots, which reveal relaxation peaks that are not observed in the dielectric loss (?″) plots, and it is found that these peaks are of a non-Debye-type. Furthermore, the frequency dependent conductivity plot shows three regions of conduction processes.     

Anomalous electric conductivity for insoluble SiO2/Pb films prepared by sputtering

Dual phase sputtered films of an insoluble SiO₂/Pb system were prepared by sputtering and their electric conductivity mechanisms were investigated. The microstructure of the sputtered films consisted of an amorphous SiO₂ phase and a crystalline fcc Pb phase. The homogeneous granular structure, where Pb particles of 5–20 nm in diameter were embedded homogeneously in a SiO₂ matrix, was observed in the Pb content of 64–71 vol.%, and the inhomogeneous granular structure, where fine and coarse Pb particles coexisted, was observed in the Pb content of 78-92 vol.%. Dissolution of Si or O into the Pb phase was not detected. The sputtered films showed a great diversity in TCR signs and inclinations according to Pb content. As Pb content decreased, the positive TCR slope decreased and changed into a negative TCR from Pb 64 vol.%. This is because as Pb content decreased, the percolation cluster composed of Pb particles, which makes metallic electric conductivity possible, diminished gradually, and electric channels disappeared finally, changing into other electric conductivity mechanisms induced from the tunneling effect of electrons. Sputtered films were conductors with high electric resistivity when they had homogeneous granular structures. This is probably due to the fabrication method, which makes atomic level control during film preparation possible. It seems that because the movement of electrons was obstructed by fine Pb particles dispersed in an insulator SiO₂ matrix and lattice defects introduced during sputtering, the mean free path length of electron was reduced drastically. Also the significantly reduced cross section area in the links of channel where the contact regions of particles that form percolation clusters also generates high resistivity. The percolation limit for this system was Pb 67 vol.%. There was an inverse relationship between ρ₂₉₃ and TCR, which corresponds to Mooji’s empirical rule, but TCR was still positive when ρ₂₉₃≥2 μΩm at certain compositions. It seems that this result is also due to the unique hybrid microstructure of these films. The electric conductivity mechanism of sputtered films was investigated using the power law of percolation electric conductivity and a result of p=4.1 was obtained. A composite cell effective-medium theory was applied to explain this result, and it was found that the sputtered films consisted of composite cells(A and B type). This coincided well with the microstructures observed by TEM.     

纳米铜基柔性导电薄膜制备现状及前景

纳米铜基导电薄膜具有高导电、高性价比且易与柔性基材结合等优点,在下一代柔性电子产品领域具有广泛的应用前景. 然而,纳米铜基导电薄膜在制备的过程中易被氧化,成为制备高导电纳米铜基导电薄膜的难题. 文中从油墨配方、印刷方法、烧结方法等方面系统地介绍了纳米铜基柔性导电薄膜的制造方法,着重介绍了目前抗氧化油墨的设计思路,阐明了目前柔性电子先进微纳连接技术的工艺流程,对比了其优缺点及适用范围,并列举了纳米铜基导电薄膜在下一代柔性电子产品领域的典型应用. 在此基础上,对纳米铜柔性导电薄膜制造尚存的主要问题进行了总结,并对其未来发展趋势进行了展望.