共查询到20条相似文献,搜索用时 15 毫秒
1.
I. Cazenobe I. Ledoux J. Zyss P. Boldt J. Wichern T. H. Kirchberger J. Rase 《Optical Materials》1998,9(1-4):280-285
Novel chromophores designed towards the elaboration of highly electro-optic (EO) polymers have been synthesized and characterized. EO doped polymers were prepared and characterised using second harmonic generation and the Teng and Man techniques at 1.3 μm for measurements of d33 and r33, respectively. The measured values of r33 (18 pm/V) in a polycarbonate matrix doped with 5.5% of chromophore qualify these materials for further elaboration in EO devices for optical signal processing. 相似文献
2.
Jérôme Steinhauser Stefan MeyerMarlène Schwab Sylvie FaÿChristophe Ballif U. KrollD. Borrello 《Thin solid films》2011,520(1):558-562
The stability in humid environment of low pressure chemical vapor deposited boron doped zinc oxide (LPCVD ZnO:B) used as transparent conductive oxide in thin film silicon solar cells is investigated. Damp heat treatment (exposure to humid and hot atmosphere) induces a degradation of the electrical properties of unprotected LPCVD ZnO:B layers. By combining analyses of the electrical and optical properties of the films, we are able to attribute this behavior to an increase of electron grain boundary scattering. This is in contrast to the intragrain scattering mechanisms, which are not affected by damp heat exposure. The ZnO stability is enhanced for heavily doped films due to easier tunneling through potential barrier at grain boundaries. 相似文献
3.
Kyung Ho Yoon 《Thin solid films》2010,519(5):1583-1586
Thin films of zinc germanate doped with manganese (Zn2GeO4:Mn) were fabricated by radio frequency magnetron sputtering, and their structural characteristics and luminescent properties were studied. The Zn2GeO4:Mn films exhibited a pronounced absorption edge at around 271 nm and a high optical transparency in the visible wavelength region with a peak transmittance of 0.927 at 691 nm. While the as-deposited Zn2GeO4:Mn films had an amorphous structure, the annealed films possessed a rhombohedral polycrystalline structure with a random crystallographic orientation of grains. The broad-band photoluminescence (PL) emission was observed from the annealed Zn2GeO4:Mn films. The PL emission spectrum showed a peak maximum at around 537 nm in the green range, which was accounted for by the intrashell transition of 3d5 orbital electrons from the 4T1 lowest excitation state to the 6A1 ground state in the divalent manganese ions. Two discrete peaks were observed in the PL excitation spectrum at 256 and 296 nm, which are considered to be associated with the band-to-band absorption of the host and the sub-band absorption from defect states, respectively. The green cathodoluminescence (CL) emission was obtained from the annealed Zn2GeO4:Mn films with a peak centered at around 534 nm, analogous to the PL emission spectrum. 相似文献
4.
High thermal stability PS-<Emphasis Type="Italic">b</Emphasis>-PEO templated mesoporous titania film
For many advanced applications, high thermal stability above 400 °C remains as a challenge for the ordered mesoporous titania
films. In this work, we attempt to increase the thermal stability of mesoporous structure in titania film crystallization
via PS-b-PEO block copolymer templating route. This paper reports the highly crystallized mesoporous titania film on silicon substrate
thermally stable at 600 °C. The photocatalytic activity of the titania mesoporous film was also shown to be twice of that
templated by F127 for degradation of methylene blue (MB). The present results also indicate that at low crystallinity, photocatalytic
activity is controlled primarily by crystal perfection rather that surface area. 相似文献
5.
Stability is essential for designing and controlling any dynamic systems. Recently, the stability of genetic regulatory networks has been widely studied by employing linear matrix inequality (LMI) approach, which results in checking the existence of feasible solutions to high‐dimensional LMIs. In the previous study, the authors present several stability conditions for genetic regulatory networks with time‐varying delays, based on M ‐matrix theory and using the non‐smooth Lyapunov function, which results in determining whether a low‐dimensional matrix is a non‐singular M ‐matrix. However, the previous approach cannot be applied to analyse the stability of genetic regulatory networks with noise perturbations. Here, the authors design a smooth Lyapunov function quadratic in state variables and employ M ‐matrix theory to derive new stability conditions for genetic regulatory networks with time‐varying delays. Theoretically, these conditions are less conservative than existing ones in some genetic regulatory networks. Then the results are extended to genetic regulatory networks with time‐varying delays and noise perturbations. For genetic regulatory networks with n genes and n proteins, the derived conditions are to check if an n × n matrix is a non‐singular M ‐matrix. To further present the new theories proposed in this study, three example regulatory networks are analysed.Inspec keywords: genetics, linear matrix inequalities, Lyapunov matrix equations, molecular biophysics, noise, proteinsOther keywords: M‐matrix‐based stability condition, genetic regulatory networks, time‐varying delays, noise perturbations, linear matrix inequality approach, high‐dimensional LMI, Lyapunov function, state variables, M‐matrix theory, proteins, nonsingular M‐matrix 相似文献
6.
《功能材料信息》2016,(1)
正The crucial challenge for current nanoscale thermal insulation materials,such as Al_2O_3 and SiO_2 aerogel composites,is to solve the trade-off between extremely low thermal conductivity and unsatisfied thermal stability.Typical high-temperature ceramic SiC possesses excellent mechanical properties and 相似文献
7.
应用于柔性显示的聚酰亚胺(Polyimide,PI)膜要求高透明性和低热膨胀系数CTE,而目前高透明聚酰亚胺的CTE普遍高于40×10?6/℃。本研究采用同质增强法,将高强度的纳米PI纤维与无色透明热塑性含氟聚酰亚胺(PI-F)复合,得到的纳米PI纤维增强PI-F基复合薄膜不仅保持PI-F的高透明,同时具有更低的CTE和优异的拉伸性能。研究结果表明:纳米尺寸的纤维可减少光透过时发生的散射,使复合薄膜维持了较高的透明性。当纳米PI纤维质量分数为10%时,在可见光区其透光率达到80.5%,与纯PI-F薄膜相比,复合薄膜的CTE值降低了40.3%,为28.3×10?6/℃。其拉伸强度提高了132.9%,达到107.6 MPa,拉伸模量增大了89.5%,达到1152.2 MPa。 相似文献
8.
采用基于密度泛函理论的第一性原理方法,计算了γ-TiAl和过渡金属Zr替位掺杂γ-TiAl形成的Ti8Al7Zr和Ti7ZrAl8体系的几何结构、总能量、结合能、声子谱和热学参量。通过对几何结构和结合能的计算分析揭示Zr替位掺杂γ-TiAl能够改善材料的稳定性和延性。能带结构和态密度表明Ti8Al7Zr和Ti7ZrAl8体系具有金属导电性。计算的声子谱显示Ti7ZrAl8体系具有很好的稳定性。计算结果显示Ti8Al7Zr和Ti7ZrAl8体系均具有较大而且稳定的高温热容量和热导率,比γ-TiAl有显著的改善。Ti8Al7Zr和Ti7ZrAl8体系的较大的热容量和热导率都有利于γ-TiAl基合金的技术应用。 相似文献
9.
Xianjie Zhou Jiwen Xu Xiaosheng Tang Qiuping Wei Zhiming Yu 《Journal of Materials Science: Materials in Electronics》2017,28(5):3997-4003
As one kind of well known amorphous transparent conductive oxide films, In–Ga–Zn–O (IGZO) based films were broadly used as electric functional layer in optoelectronic devices. As IGZO film is sensitive to temperature and oxygen, and its electrical and optical properties may probably be deteriorated after subsequent high temperature and air atmosphere. In this work, amorphous indium tin oxide (ITO) layer with two adjustable type of thickness were employed to improve the thermal stability of IGZO films. The doubled ITO/IGZO films were deposited on glass by magnetron sputtering and annealed at high temperatures subsequently to investigate its thermal stability. Accordingly, the crystal structure, optical and electrical properties of ITO/IGZO films were further studied. The XRD results demonstrated that the annealed IGZO films could keep amorphous structure, and the ITO/IGZO films were consisted of uniform small particles which showed comparable dense structure and closely integration with the glass substrate. Furthermore, the sheet resistance results indicated that the increased thickness of top ITO film could suppress oxygen and improve thermal stability of electrical property. Moreover, the transmittance in the visible range was about 85%, and showed a little increase after annealing. The protective ITO layer was found to keep improved thermal stability, good electrical and optical properties at temperatures up to 550 °C. 相似文献
10.
Jong-Keuk Park 《Thin solid films》2008,516(11):3661-3664
This study investigated the effects of a nanoscale multi-layered structure on the hardness and thermal stability of Ti-Al-B-N coating. Bilayer period of nanoscale multi-layered TiAlN/BN coating, prepared by alternating deposition of TiAlN and BN layers, was controlled by changing BN target power. The hardness value of TiAlN coating increased through nanoscale multi-layered structurization with a thin (∼ 0.6 nm) BN phase. The intensity of low angle XRD peaks and hardness of the nanoscale multi-layered TiAlN/BN coatings increased after heat-treatment in an N2 atmosphere. The nanoscale multi-layered TiAlN/BN coating showed better thermal stability than that of TiAlN coating. 相似文献
11.
12.
Thin films of arsenic triselenide doped with silver were prepared by thermal evaporation of the bulk-quenched materials. Structural investigations have been carried out by using X-ray diffraction and X-ray fluorescence. The differential scanning calorimetry is used to measure the glass transition temperature of the samples under investigation. The Swanepoel method based on the use of the maxima and minima in the interference fringes has been successfully utilized for accurate determination of the film thickness and optical parameters. The technique used took into consideration the non-uniform nature in the film thickness. Using the exact calculation of the film thickness the real refractive index, the extinction coefficient, the optical bandgap energy and the oscillator and dispersion energies were obtained as a function of the silver contents. The DC conductivity was found to depend on the silver content. 相似文献
13.
E.A. CarvalhoA.P. Carmo M.J.V. Bell V. AnjosL.R.P. Kassab D.M. da Silva 《Thin solid films》2012,520(7):2667-2671
The present work reports on the thermo-optical study of germanate thin films doped with Au and Ag nanoparticles. Transmission Electron Microscopy images, UV-visible absorption and Micro-Raman scattering evidenced the presence of nanoparticles and the formation of collective excitations, the so called surface plasmons. Moreover, the effects of the metallic nanoparticles in the thermal properties of the films were observed. The thermal lens technique was proposed to evaluate the Thermal Diffusivity (D) of the samples. It furnishes superficial spatial resolution of about 100 μm, so it is appropriate to study inhomogeneous samples. It is shown that D may change up to a factor 3 over the surface of a film because of the differences in the nanoparticles concentration distribution. 相似文献
14.
Hyun Soo Shin Byung Du Ahn Kyung Ho Kim Jin-Seong Park Hyun Jae Kim 《Thin solid films》2009,517(23):6349-249
In this paper, the effects of thermal annealing and the plasma treatment sequence on the performance of amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) without conventional source/drain (S/D) layer deposition were investigated. We fabricated TFTs using two different processes, one where S/Ds were plasma-treated after thermal annealing, the second where the S/Ds were plasma-treated before annealing. The performance of the former exhibited a linear mobility of 4.97 cm2/V s, an on/off ratio of 4.6 × 106, a Vth of 2.56 V, and a subthreshold slope of 0.65 V/decade. However, the TFT parameters of the latter sample were reduced to a linear mobility of 0.07 cm2/V s, an on/off ratio of 1.5 × 105, a Vth of 2.33 V, and a subthreshold slope of 3.54 V/decade. It was shown that the sheet resistance of plasma-treated S/D areas increased after thermal annealing by about three orders of magnitude. As a result, the increase of the sheet resistance caused a decrease of TFT performance. 相似文献
15.
采用化学共沉淀煅烧法制备不同La2O3掺杂量的La2O3-Y2O3-ZrO2(YSZ)复合陶瓷粉末,研究该复合陶瓷粉末的高温相稳定性、抗烧结性及热物理性能,并与传统应用的YSZ陶瓷粉末进行对比,以探讨La2O3-YSZ作为热障涂层材料应用的可能性。采用XRD分析陶瓷粉末的晶体结构和物相组成,研究La2O3掺杂量对YSZ高温相稳定性的影响。采用SEM观察陶瓷烧结体的微观形貌,研究La2O3掺杂对YSZ抗烧结性的影响。采用激光脉冲法测定热扩散率,通过计算得到材料的热导率。结果表明:YSZ和不同La2O3掺杂量的La2O3-YSZ均由单一的非平衡四方相ZrO2(t′-ZrO2)组成。经1 400℃热处理100h后,YSZ中t′-ZrO2完全转变为立方相ZrO2(c-ZrO2)和单斜相ZrO2(m-ZrO2),在0.4mol%~1.4mol%La2O3掺杂范围内,La2O3-YSZ的相稳定性均优于YSZ,其中1.0mol%La2O3掺杂的YSZ(1.0mol%La2O3-YSZ)经热处理后无m-ZrO2生成,表现出良好的高温相稳定性。此外,1.0mol%La2O3-YSZ较YSZ具有较高的抗烧结性和较低的热导率。在室温至700℃范围内,1.0mol%La2O3-YSZ的热导率为1.90~2.17 W/(m·K),明显低于YSZ的热导率(2.13~2.33 W/(m·K))。 相似文献
16.
A laboratory experiment was conducted to evaluate enhanced pesticidal activity of silica nanoparticles‐doped chitinase nano enzyme conjugate against an economically important insect pest Spodoptera litura (Fab.) (Lepidoptera; Noctuidae). Silica nanoparticles were synthesized by hydrolysis and condensation of precursor tetraethylorthosilicate (TEOS) followed by functionalization with functioning agent 3‐aminopropyltriethoxysilane. Functionalized silica nanoparticles thus acquired were doped with chitinase enzyme produced by Serratia marcescens SU05. Doped nanosilica–chitinase nano enzyme conjugate was loaded with pesticidal plant extracts to study the improved pesticidal activity. Synthesized nano enzyme conjugate revealed high stable, monodisperse spherical nanoparticles and exhibited effective loading with respective plant extracts. Nano enzyme conjugates and plant extracts loaded with nano enzyme conjugate recorded high rate of mortality against the larval instars and brought about a distinct effect on the life stage parameters of S.litura. Non‐target toxic effect of nano enzyme conjugate was carried out by determination of lethality and changes in protein profiling against brine shrimp (Artemia salina) that shows less lethality and no distinct changes in protein profiling which suggest the effective utilization of silica nanoparticles doped chitinase as an insecticidal agent against economically important insect pests associated with various crops. 相似文献
17.
Cu/Mo/Si multi-layer structures were fabricated to investigate diffusion behaviors and thermal stability between Cu and Mo. Physical vapor deposition (PVD), chemical vapor deposition, electroplating and electrolessplating were used to grow 100 nm thick Cu films as interconnection materials, and radio-frequency sputtering system was introduced to grow 37.5 nm thick Mo films as a buffer layer. All Cu/Mo/Si multi-layer specimens were annealed at 350 to 700 °C for 30 min. When the annealing temperature was over 600 °C, the Cu diffused through Mo into Si, and the Cu3Si phase and Mo-Si intermetallic compounds formed at the Mo/Si interface. The diffusion mechanism is the grain boundary diffusion. The results indicate that Cu film deposited by PVD had best crystallinity, lower roughness, large adhesive energy and resistivity. The values of the resistivity, diffusion activity energy and large adhesive energy are 5.47 μΩ-cm, 0.948 eV and 2.46 N/m, respectively. 相似文献
18.
Weihua Wu Yifeng Hu Xiaoqin Zhu Yongxing Sui Li Yuan Long Zheng Hua Zou Yuemei Sun Sannian Song Zhitang Song 《Journal of Materials Science: Materials in Electronics》2016,27(3):2183-2188
In comparison to Ge2Sb2Te5 (GST) and pure Sb70Se30 (SbSe) thin films, superlattice-like (SLL) Ge/Sb70Se30 (Ge/SbSe) has a higher crystallization temperature, larger crystallization activation energy, better data retention and lower power consumption. SLL Ge/SbSe thin films with different thickness of Ge and SbSe layers were prepared by magnetron sputtering system. The amorphous-to-crystalline transitions of SLL Ge/SbSe thin films were investigated through in situ film resistance measurement. The crystallization activation energy of SLL Ge/SbSe thin films was calculated from a Kissinger plot. The data retention time was estimated through isothermal time-dependent resistance measurement by Arrhenius equation. The phase structure of the thin films annealed at different temperatures was investigated by using X-ray diffraction. Phase change memory cells based on the SLL [Ge(8 nm)/SbSe(5 nm)]4 thin films were fabricated to test and evaluate the switching speed and operation consumption. 相似文献
19.
Jong Hoon Kim 《Thin solid films》2008,516(7):1529-1532
Coplanar type transparent thin film transistors (TFTs) have been fabricated on the glass substrates. The devices consist of intrinsic ZnO, Ga doped ZnO (GZO), and amorphous HfO2 for the semiconductor active channel layer, electrode, and gate insulator, respectively. GZO and HfO2 layers were prepared by using a pulsed laser deposition (PLD) and intrinsic ZnO layers were fabricated by using an rf-magnetron sputtering. The transparent TFT exhibits n-channel, enhancement mode behavior. The field effect mobility, threshold voltage, and a drain current on-to-off ratio were measured to be 14.7 cm2/Vs, 2 V, and 105, respectively. High optical transmittance (> 85%) in visible region makes ZnO TFTs attractive for transparent electronics. 相似文献