Relation between powder size and electrolyte properties in nano YSZ system

YSZ (yttria stabilized zirconia) electrolyte properties made from different sizes of nano powders were investigated. As a result, the sample marked KD with the smallest size (10 nm) of first particles and the sample marked TH with narrow distribution and the smallest median diameter Mmcd of 0.49μm have the best sintering properties and the highest electrical conductivity. There is a very well correlation between the density and the electrical conductivity of YSZ, that is, the samples with a higher density have a higher electrical conductivity. The area resistance of YSZ electrolyte made in the experiment, such as TH of 0.483 Ω.cm^2, is much lower than that of the sample D of 1.300 Ω.cm^2 made in Germany at 850℃. The complex resistance of YSZ electrolyte made in the experiment at the grain, grain boundary and electrode in the range of 300-750℃ decreases greatly compared to the sample made in Germany by shown in the complex impedance plot.     

单晶碳和锗薄膜热导率的分子动力学模拟

采用非平衡分子动力学(NEMD)方法分别模拟碳和锗纳米薄膜的法向热导率.模拟结果表明:厚度为2~5nm的碳晶体薄膜在温度为300~500 K的法向热导率显著小于对应的大体积晶体的实验值,并随薄膜厚度的增加而增加,法向热导率与薄膜厚度呈近似线性关系;厚度为2.8175~11.27nm的单晶锗纳米薄膜在温度为300~500 K时的法向热导也存在明显的尺寸效应,薄膜的热导率与其厚度呈近似线性关系,并且随着薄膜厚度的增加而增加.     

Influence of thickness on the properties of solution-derived LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript> thin films

LiMn₂O₄ thin films of different thickness were derived from solution deposition and heat treated by rapid thermal annealing. The phase identification and surface morphology were studied by X-ray diffraction and scanning electron microscopy. The electrochemical properties of the films were examined by galvanostatic charge-discharge experiments and electrochemical impedance spectroscopy. LiMn₂O₄ thin films of different thickness derived from solution deposition and rapid thermal annealing are homogeneous and crack free with the grain size between 20 nm and 50 nm. The specific capacity of these films is between 42 and 47 μAh·cm²·μm⁻¹. The capacity decreases with the increase of discharge current density. The capacity loss per cycle increases from 0.012% to 0.16% after being cycled 50 times as the film thickness increases from 0.18 μm to 1.04 μm. The lithium diffusion coefficients of these films are in the same order of 10⁻¹¹ cm²·s⁻¹.     

Research of Current Mode Atomic Force Microscopy (C-AFM) for Si/SiC Heterostructures on 6H-SiC(0001)

Si/SiC heterostructures with different growth temperatures were prepared on 6 HSiC(0001) by LPCVD. Current mode atomic force microscopy and transmission electron microscopy were employed to investigate the electrical properties and crystalline structure of Si/SiC heterostructures. Face-centered cubic(FCC) on hexagonal close-packing(HCP) epitaxy of the Si(111)/SiC(0001) heterostructure was realized at 900°C. As the growth temperature increases to1 050°C, the 110 preferred orientation of the Si film is observed. The Si films on 6 H-SiC(0001)with different growth orientations consist of different distinctive crystalline grains: quasi-spherical grains with a general size of 20 μm, and columnar grains with a typical size of 7 μm×20 μm. The electrical properties are greatly influenced by the grain structures. The Si film with 110 orientation on SiC(0001) consists of columnar grains, which is more suitable for the fabrication of Si/SiC devices due to its low current fluctuation and relatively uniform current distribution.     

磁控溅射参数对钛薄膜结构及阳极氧化的影响

采用直流磁控溅射的方法在导电玻璃(FTO)上制备柱状晶结构的钛薄膜,研究了磁控溅射电流和基底温度对溅射钛薄膜微观结构的影响,分析了柱状晶结构对后续阳极氧化TiO2纳米管结构的影响.利用场发射扫描电镜观察样品的形貌,X射线衍射(XRD)分析样品的晶型结构.结果表明,随着磁控溅射电流的增大,钛薄膜的晶粒尺寸增加,致密度先增大后减小,溅射电流过大过小都会降低薄膜的致密度;在300～450℃的温度区间,随基底温度的升高,钛薄膜的晶粒尺寸增加,致密度增加,柱状晶结构更均匀.将磁控溅射获得的钛薄膜进行阳极氧化处理,结果发现:排列致密的柱状晶钛薄膜有利于生长TiO2纳米管.     

Preparation and magnetic properties of Co-P thin films

Magnetic Co-P thin films were prepared by electroless deposition. The experiment results show that the film thickness has a significant influence on the coercivity. While the film thickness varied from 300 nm to 5 μm,the coercivity dropped sharply from 45.36 to 22.28 kA/m. As the film thickness increased further,the coercivity varied slowly. When the thickness of the film was 300 nm,the deposited film could realize the coercivity as high as 45.36 kA/m,and the remanent magnetization as high as 800 kA/m .The ...     

Influence of the Source to Substrate Distance on the Growth,Tribological Properties and Optical Properties of Be Films

The Be films were prepared by thermal evaporation at different sources to substrate distances (SSD) on glass substrates. The decrease of SSD from 90 mm to 50 mm caused the increase of substrate temperature and the rising density of incident Be atoms, thus the properties of Be films greatly changed accordingly. The experimental results showed that the grain diameter in the Be films transited from below 100 nm to 300 nm, the film growth rate increased from 2.35 nm/min to 4.73 nm/min and the roughness increased from 7 nm to 49 nm. The performance study suggested that the friction coefficient of Be films increased from 0.13 to 0.27 and was related to the surface roughness and inner structure, the near-infrared reflectance of Be films increased from 40% to 85% with the increase of wavelength and concurrently decreased with the decrease of SSD, respectively. The performance study indicated that the Be film had the potential application in specific near-infrared reflectance optical system.     

LiTaO3薄膜红外探测器热分析

利用有限元软件ANSYS对LiTaO3薄膜热释电红外探测器进行热分析;研究了敏感元绝热层的厚度与热导率以及基底的厚度及材料对热分析结果的影响;提出了优化方案,并给出优化前后仿真的对比结果。分析结果表明,探测器的热响应随绝热层的厚度增加而增加,随绝热层的热导率降低而增加。在硅、镍、蓝宝石三种基底材料中,使用蓝宝石的探测器的热响应效果最佳。在绝热层厚度为2 μm的情况下,基底的厚度对探测器响应的影响可以忽略。实验测试结果证实了优化模型的有效性。     

基板法催化生长纳米碳纤维薄膜

以乙炔(C2H2)为碳源,铜溶胶和硫化铜为催化剂前躯体,采用化学气相沉积法(CVD)在玻璃基板上生长纳米碳纤维薄膜。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线衍射仪(XRD)对产物的形貌与结构进行了表征。结果表明:在反应温度为350℃时,制备出了纤维直径为100～200nm,厚度为3～20μm的均匀的纳米碳纤维薄膜;随着反应温度升高或者反应时间的延长,纳米碳纤维薄膜的膜厚增厚。     

基片表面朝向对ZnO纳米线生长机理的影响

采用热蒸发ZnO粉末法,以金膜为催化剂,在两片表面分别朝上和朝下的Si(100)基片上生长ZnO纳米线(样品分别标为1#和2#)。X射线衍射(XRD)图谱上只存在ZnO的(002)衍射峰,说明ZnO纳米线沿(001)择优取向。通过扫描电子显微镜(SEM)表征发现,ZnO纳米线整齐排列在Si基片上,直径在100nm左右,平均长度为4mm。通过分析得出,两种基片上生长的ZnO纳米线的生长机理是不相同的:1#样品,在基片表面上先生长ZnO薄膜,再在薄膜上生长ZnO纳米线;2#样品,ZnO纳米线直接外延生长在基片表面。结果显示基片表面的朝向影响ZnO纳米线的生长机理。     

Preparation and electrical properties of BaPbO3 thin film

BaPbO3 thin films were deposited on Al2O3 substrates by sol-gel spin-coating and rapid thermal annealing. The microstructure and phase of BaPbO3 thin films were determined by X-ray diffractometry, scanning electrons microscopy and energy dispersive X-ray spectrometry. The influence of annealing temperature and annealing time on sheet resistance of the thin films was investigated. The results show that heat treatment, including annealing temperature and time, causes notable change in molar ratio of Pb to Ba, resulting in the variations of sheet resistance. The variation of electrical properties demonstrates that the surface state of the film changes from two-dimensional behavior to three-dimensional behavior with the increase of film thickness. Crack-free BaPbO3 thin films with grain size of 90 nm can be obtained by a rapid thermal annealing at 700 ℃ for 10 min. And the BaPbO3 films with a thickness of 2.5 μm has a sheet resistance of 35 Ω·-1.     

衬底效应对LiTaO3薄膜制备的影响

用溶胶凝胶法在N型硅、P型硅、石英、铂、镍衬底上制备了钽酸锂(LiTaO3)薄膜,用XRD和SEM对钽酸锂薄膜性能参数进行了表征;发现掺杂少量环氧树脂能提高钽酸锂薄膜的均匀性,改善薄膜与衬底的粘附性;研究了衬底效应与薄膜厚度的关系,薄膜厚度超过0.2 μm,Ni衬底的XRD峰值强度几乎不再出现,说明衬底对薄膜初始结晶取向有重要影响;利用不同衬底上生长钽酸锂薄膜,XRD研究结果表明:N型硅、P型硅、石英衬底上只能制备多晶钽酸锂薄膜,铂衬底上制备的钽酸锂薄膜在(012)晶向有强大的择优取向性,镍衬底上制备的钽酸锂薄膜有更好的C轴择优取向性,C轴择优取向系数可达0.082。     

溶胶凝胶法制备透明氧化铝薄膜及光学性能

以异丙醇铝为先驱体,采用溶胶凝胶方法制备了透明氧化铝薄膜;并采用DTA-TG,XRD, UV-vis分光光度计和PL光谱等测试手段对氧化铝薄膜进行表征.研究结果表明, 氧化铝薄膜(膜厚为100 nm) 在紫外到近红外范围内具有高的透射性,750 ℃热处理后氧化铝薄膜的光透射性最好;氧化铝薄膜在360-600 nm波长范围具有一个宽的蓝色发光带,且氧化铝膜的光致发光强度和峰位与热处理温度和激发光波长有关, 在345 nm 波长激发下,500 ℃热处理后氧化铝薄膜的发光强度最强;氧化铝薄膜的蓝色发光由氧空位缺陷(F+色心)引起.     

Preparation of ZAO film by low-temperature hydrothermal approach and its electrical property

Al-doped ZnO (ZAO) films were successfully deposited on the surface of common glasses by using low-temperature hydrothermal approach. In the reaction solution, the molar ratio of Al3+ to Zn2+ was 1∶100, the annealing temperature and time were 200 ℃ and 2-6 h, respectively. The structure of the thin films was identified by X-ray diffraction (XRD), the surface morphology and thickness of the thin films were observed by scanning electron microscopy (SEM), and the electrical performance of the thin films was measured by four-point probes. It was shown that the films with an average particle size of 27.53 nm had a preferential orientation along (002), Al3+ had replaced the position of Zn2+ in the lattice without forming the Al2O3 phase and its thickness was 20-25 μm. With the increased annealing time, the intensity of diffraction peaks was decreased, the film exhibited irregular surface morphology gradually, and the resistivity of ZAO films was increased. The lowest resistivity obtained in this study was 3.45×10-5Ω·cm.     

磁控溅射CdTe薄膜的光电学特性

采用射频磁控溅射方法在玻璃和Si(111)衬底上制备了碲化镉(CdTe)薄膜,并研究了溅射功率对薄膜的结构、光学和电学性能的影响.X射线衍射分析表明,所有样品均沿(111)面择优取向; 平均晶粒尺寸随溅射功率的增加而增加,即从73.0 nm(70 W)增加到123.6 nm(110 W).紫外 - 可见 - 近红外光谱分析表明, CdTe薄膜在可见光范围内具有较高的吸光度; 薄膜的带隙随着溅射功率的增加而减小,最小值为1.38 eV.CdTe薄膜的导电性随溅射功率的增加而明显增强,当溅射功率为110 W时电阻率仅为21.5 Ω?cm.该研究结果可为制备高导电性和高吸收率的半导体薄膜提供参考.     

纳米碳纤维薄膜的制备及其疏水性能

采用化学气相沉积(CVD)方法,以乙炔(C2H2)为碳源,直接于铜基板上生长碳纤维薄膜。铜基板只进行简单的打磨处理。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)对产物的形貌、结构进行了表征,并用接触角测量仪(CA)对制备的碳纤维薄膜进行疏水性测试。结果表明:在铜基板表面制备了一层直径为100～200nm,厚度为40～50μm的碳纤维薄膜。疏水测试结果显示,这种薄膜有较好的疏水性能,且随纳米碳纤维合成温度变化而变化。经多次试验表明,铜片具有良好的循环使用性能,可多次用于制备碳纤维薄膜。     

Influence of argon gas pressure on the ZnO:Al films deposited on flexible TPT substrates at room temperature by magnetron sputtering

Aluminium doped ZnO thin films(ZnO︰Al) were deposited on transparent polymer substrates at room temperature by rf magnetron sputtering method from a ZnO target with Al2O3 of 2.0 wt%. Argon gas pressure varied from 0.5 Pa to 2.5 Pa with radio frequency power of 120 W. XRD results showed that all the ZnO︰Al films had a polycrystalline hexagonal structure and a (002) preferred orientation with the c-axis perpendicular to the substrate. The grain sizes of the films were 6.3-14.8 nm.SEM images indicated the ZnO︰Al film with low Argon gas pressure was denser and the deposition rate of the films depended strongly on the Argon gas pressure, increasing firstly and then decreasing with increasing the pressure. The highest deposition rate was 5.2 nm/min at 1 Pa. The optical transmittance of the ZnO︰Al films increased and the blue shift of the absorption edge appeared when the Argon gas pressure increased. The highest transmittance of obtained ZnO︰Al films at 2.5 Pa was about 85% in the visible region. The electrical properties of the films were worsened with the increase of the Argon gas power from 1 Pa to 2.5 Pa. The resistivity of obtained film at 1.0 Pa was 2.79×10-2 Ω·cm.     

离子束辅助沉积非晶硅薄膜红外光学特性研究

为了得到非晶硅（a-Si）薄膜红外光学常数与工艺参数之间的关系,采用Ar离子束辅助电子束热蒸发技术制备a-Si薄膜,并利用椭偏仪和分光光度计测量了薄膜的光学常数,分析了薄膜沉积速率、基底温度和工作真空度对a-Si薄膜折射率和消光系数的影响.实验结果表明：影响a-Si薄膜光学常数的主要工艺因素是沉积速率和基底温度,工作真空度的影响最小.当沉积速率和基底温度升高时,薄膜的折射率先增大后减小;当工作真空度升高时,薄膜的折射率增大.在波长1~5μm之间,a-Si薄膜的折射率变化范围为2.47~3.28.     

衬底和热处理温度对ZnO薄膜的微观结构的影响

采用Sol-gel法,在普通载玻片和Si（100）上使用旋转涂覆技术制备了具有c轴择优取向生长的ZnO薄膜。利用XRD和SEM研究了衬底和热处理温度对ZnO薄膜的物相结构、表面形貌和（002）定向性的影响。结果表明,sol—gel旋涂法制备的ZnO薄膜为六角纤锌矿结构,玻璃衬底上生长的ZnO薄膜为多晶形态,Si（100）衬底表现出更优取向生长特性。随着热处理温度的升高,c轴择优取向程度逐渐增强,晶粒尺寸逐渐增大,ZnO的晶格参数先增加后减小。当温度在700℃时长出明显的柱状晶粒。     

Improved visible transparency of SIO<Subscript>2</Subscript>/ZNO:AL /CEO<Subscript>2</Subscript>-TIO<Subscript>2</Subscript>/SIO<Subscript>2</Subscript> multilayer films with high UV absorption and infrared reflection rate

New visible transparent, UV absorption, and high infrared reflection properties have been realized by depositing multilayer SiO₂/ZnO: Al/CeO₂-TiO₂/SiO₂ films onto glass substrates at low temperature by radio frequency magnetron sputtering. Optimum thickness of SiO₂, ZnO: Al (ZAO) and CeO₂-TiO₂ (CTO) films were designed with the aid of thin film design software. The degree of antireflection can be controlled by adjusting the thickness and refractive index. The outer SiO₂ film can diminish the interference coloring and increase the transparency; the inner SiO₂ film improves the adhesion of the coating on the glass substrate and prevents Ca²⁺, Na⁺ in the glass substrate from entering the ZAO film. The average transmittance in the visible light range increases by nearly 18%-20%, as compared to double layer ZAO/CTO films. And the films display high infrared reflection rate of above 75% in the wavelength range of 10-25 μm and good UV absorption (> 98%) properties. These systems are easy to produce on a large scale at low cost and exhibit high mechanical and chemical durability. The triple functional films with high UV absorption, antireflective and high infrared reflection rate will adapt to application in flat panel display and architectural coating glass, automotive glass, with diminishing light pollution as well as decreasing eye fatigue and increasing comfort.