纳米TiO_(2)对NH_(3)-H_(2)O-LiBr工质降膜吸收性能的影响

为了探讨纳米TiO_(2)对三元NH_(3)-H_(2)O-LiBr工质降膜吸收的影响,本文利用数值分析建立了三元工作流体薄膜吸收的连续方程、能量方程和组分质量平衡方程,采用Matlab软件进行编程和计算纳米流体的降膜吸收性能,将其与实验数据进行对比验证,并进一步分析了纳米TiO_(2)质量分数、初始氨浓度、初始温度、冷却水进口温度、吸收压力和下降薄膜管长度对薄膜吸收性能的影响。研究表明:添加纳米TiO_(2)可以增强降膜吸收的传质速率,主要原因为液膜中氨的扩散系数增加。当纳米TiO_(2)质量分数从0%增加到0.1%、0.3%和0.5%时,扩散系数分别增加了3.44倍、6.42倍和11.76倍。此外,增加初始氨浓度、降低初始温度、提高冷却水进口温度或降低吸收压力都可以提高最终溶液的饱和度。

Investigation of Sprayed Lu2O3 Thin Films Using XPS

Spray pyrolysis method was used to deposit Lutetium Oxide (Lu2O3) thin films using lutetium (III) chloride as source material and water as oxidizer. Annealing was carried out in argon atmosphere at 450°C for 60 minutes of the films. To investigate the composition and stoichiometry of sprayed as-deposited and annealed Lu2O3 thin films, depth profile studies using X-ray photoelectron spectroscopy (XPS) was done. Nearly stoichiometric was observed for both annealed and as-deposited films in inner and surface layers.

XPS Depth Profile Study of Sprayed Ga2O3 Thin Films

Ga2O3 thin films were fabricated by spray pyrolysis method using gallium acetylacetonate as source material and water as oxidizer. The films were annealed at 450°C for 60 minutes in argon atmosphere. X-ray photoelectron spectroscopy (XPS) depth profile studies were carried out to analyze the stoichiometry and composition of sprayed as-deposited and annealed Ga2O3 thin films. Surface layers and the inner layers of as-deposited and annealed films were found nearly stoichiometric.

Effects of dopant content on optical and electrical properties of In_2O_3: W transparent conductive films

The In 2 O 3 : W (IWO) films with different W content were deposited on glass substrate using direct current sputtering method. The structure, surface morphology, and optical and electrical properties were investigated. Results showed that both the carrier concentration and carrier mobility were increased with the doping of W. The IWO film with the lowest resistivity of 1.0×10 3 cm, highest carrier mobilityof 43.7 cm 2 V 1 s 1 and carrier concentration of 1.4×10 20 cm 3 was obtained at the content of 2.8 wt.%. The average optical transmittance from 300 nm to 900 nm reached 87.6%.

Effects of thickness on superconducting properties and structures of Y_2O_3/BZO-doped MOD-YBCO films

We report the thickness dependence of critical current density （Jc） in YBa2Cu3O7-x （YBCO） films with BaZrO3 （BZO） and Y2O3 additions grown on single crystal LaAlO3 substrates by metalorganic deposition using trifluoroacetates （TFA-MOD）. Comparing with pttre YBCO films, the Jc of BZO/Y2O3-doped YBCO films was significantly enhanced. It was also found that with the increase of the thickness of YBCO film from 0.25 μm to 1.5 μm, the Ic of BZO/Y2O3-doped YBCO film increased from 130 A/cm to 250 A/cm and yet Jc of YBCO film decreased from 6.5 MA/cm2 to 2.5 M A/cm2. The thick BZO/Y2O3-doped MOD-YBCO film showed lower Jc, which is mainly attributed to the formation of a-axis grains and pores.

Amorphous Er_2O_3 films for antireflection coatings

This paper reports that stoichiometric, amorphous, and uniform Er2O3 films are deposited on Si（001） substrates by a radio frequency magnetron sputtering technique. Ellipsometry measurements show that the refractive index of the Er2O3 films is very close to that of a single layer antireflection coating for a solar cell with an air surrounding medium during its working wavelength. For the 90-nm-thick film, the reflectance has a minimum lower than 3% at the wavelength of 600 nm and the weighted average refiectances （400-1000 nm） is 11.6%. The obtained characteristics indicate that Er2O3 films could be a promising candidate for antireflection coatings in solar cells.

高迁移率透明导电In_2O_3:Mo薄膜

用直流磁控溅射法成功制备了高价态差掺钼氧化铟(IMO)透明导电薄膜。研究了氧分压,基板温度以及溅射电流对IMO薄膜结构和性能的影响。获得的IMO薄膜的最低电阻率为3.65×10-4Ω·cm,载流子迁移率高达50cm2V-1s-1,可见光区域的平均透射率(含玻璃基底)高于80%。X ray衍射(XRD)研究表明IMO薄膜具有良好的结晶性。分析认为IMO薄膜的载流子迁移率主要受晶界散射的控制。

室温直流反应磁控溅射制备透明导电In_2O_3∶Mo薄膜

在室温条件下采用直流反应磁控溅射法制备了新型透明导电In2O3:Mo薄膜.研究了溅射压强中氧气百分含量[P(O2)]为8.0%～18.0%时对薄膜光电特性以及表面形貌结构的影响.结果表明,薄膜的光电性能对溅射压强中P(O2)非常敏感.分析显示P(O2)决定了薄膜中的氧空位含量和载流子浓度,从而影响了薄膜的光电特性.原子力显微镜观察表明,适量的P(O2)条件下可以获得平均粗糙度为0.3 nm、颗粒均匀、表面平整的薄膜.室温制备的IMO薄膜在可见光区域的平均透射率(含玻璃基底)高达82.1%,电阻率低至5.9×10-4 Ω·cm.

Electron Cyclotron Resonance Plasma-Assisted Atomic Layer Deposition of Amorphous Al_2O_3 Thin Films

Without extra heating, Al2O3 thin films were deposited on a hydrogen-terminated Si substrate etched in hydrofluoric acid by using a self-built electron cyclotron resonance （ECR） plasma-assisted atomic layer deposition （ALD） device with Al（CH3）3 （trimethylaluminum; TMA） and O2 used as precursor and oxidant, respectively. During the deposition process, Ar was in- troduced as a carrier and purging gas. The chemical composition and microstructure of the as-deposited Al2O3 films were characterized by using X-ray diffraction （XRD）, an X-ray photo- electric spectroscope （XPS）, a scanning electron microscope （SEM）, an atomic force microscope （AFM） and a high-resolution transmission electron microscope （HRTEM）. It achieved a growth rate of 0.24 nm/cycle, which is much higher than that deposited by thermal ALD. It was found that the smooth surface thin film was amorphous alumina, and an interfacial layer formed with a thickness of ca. 2 nm was observed between theAl2O3 film and substrate Si by HRTEM. We conclude that ECR plasma-assisted ALD can growAl2O3 films with an excellent quality at a high growth rate at ambient temperature.

A Modified Lattice Model of the Reversible Effect of Axial Strain on the Critical Current of Polycrystalline REBa2Cu3O7-δ Films

The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain 0 and the irreversible strain εirr. By introducing the applied strain, a modified grain boundaries （GBs） in the REBCO film is developed. lattice model combining the strain and misorientation of A good agreement of the calculation on the lattice model with the experimental data shows that the lattice model is able to well describe the reversible effect of axial strain on the critical current of the REBCO film, and provides a good understanding of the mechanism of the reversible effect of the strain. Moreover, the effects of the crystallographic texture of the REBCO film and the residual strain εr on the variation of the critical current with the applied strain are extensively investigated. Furthermore by using the developed lattice model, the irreversible strain εirr of the REBCO film can be theoretically determined by comparing the calculation of the critical current-strain curve with the experimental data.

The transverse laser induced thermoelectric voltages in step flow growth (1-x)Pb(Mg_(1/3)Nb_(2/3))O_(3-x)PbTiO_3 thin films

This paper reports that the transverse laser induced thermoelectric voltages （LITV） axe observed for the first time in the step flow growth （1- x）PD（Mg1/3Nb2/3）O3-xPbTiO3 （PMN-PT, x = 0.20, 0.33, 0.50） thin films deposited on vicinal-cut strontium titanate single crystal substrates. Because lead magnesium niobate-lead titanate is a solid solution of lead magnesium niobate （PMN） and lead titanate （PT）, there are two types of signals. One is wide with a time response of a microsecond, and the other superimposed with the wide signal is narrow with a time response of a nanosecond. The transverse LITV signals depend on the ratio of PMN to PT drastically. Under the irradiation of 28-ns pulsed KrF excimer laser with the 248-nm wavelength, the largest induced voltage is observed in the 0.50Pb（Mg1/3Nb2/3）O3-0.50 PbTiO3 films. Moreover, the effects of film thickness, substrates, and tilt angles of substrates are also investigated.

Y_（1－x）Nd_xSr_2Cu_（2．7）Mo_（0．3）O_（7－δ）体系的拉曼和红外光谱研究

利用拉曼散射和红外吸收光谱研究了Ｙ１－ｘＮｄｘＳｒ２Ｃｕ２．７Ｍｏ０．３Ｏ７－δ（ｘ＝０，０．２，０．５，０．８，１．０）系列样品的声子振动性质。实验结果表明，对ｘ＝０的样品，在拉曼光谱中主要出现３２３，４４３，５２２和５７８ｃｍ－１几个特征峰，在中红外吸收光谱中出现５２２，５８０和６４６ｃｍ－１特征峰。随着样品中Ｎｄ组分的增加，３２３ｃｍ－１峰向低波数发生位移，而５２２和６４６ｃｍ－１峰则向高波数发生位移。本文对这些振动模进行了指认。

活性环境空心阴极溅射特性与沉积Al_2O_3、ZnO掺杂和In_2O_3:Mo薄膜的应用(中)

2实验结果和讨论 2．1阴极和沉积特性 典型空心阴极I-V，特性如图2所示，HC中有铜靶块并用氩气作为工作气体。在气流量和放电电流一定时，压强越低需放电电压越高。在给定真空室压强情况下，两个不同气流量的I-V特性很接近，在一定电流下，较高的气流量电压略低一点（注：

活性环境空心阴极溅射特性与沉积Al_2O_3、ZnO掺杂和In_2O_3:Mo薄膜的应用(上)

研究了薄膜沉积方法,基于空心阴极金属溅射,在基材附近提供反应气体。工作气体和携带溅射原子通过一个狭长通道从阴极出来,这样,反应气体被阻止到达靶面。用Cu靶和脉冲电源激励,研究了阴极的基本运作。研究包括沉积率对电源、压强、气体流量和膜厚分布的依存关系,以及膜电阻率作为基材上的状态函数。用模型进行计算气体的速度分布和在腔内的压强,Al2O3膜是在氧的活性环境下溅射一个Al靶获得的,必须指出只要极少量氧气通过阴极就能氧化(中毒)靶,而外面大量氧气完全不会影响靶,在后者模式下实现了非常稳定的放电且易形成的Al2O3薄膜。利用该方法制备透明的ZnO导电膜,掺杂Al或B,达到了高沉积率,且在适当氧流量下得到了低的膜电阻率。同时,制备了高迁移率的In2O3:Mo透明导电膜,电阻率仅有1.9×10-4Ω·cm。给出了空心阴极的比例关系、沉积效率,比较了磁控溅射和直线的活性环境空心阴极溅射。

Upconversion properties of Y_2O_3:Er films prepared by sol-gel method

Y2O3：Er^3＋ films were prepared by a simple sol-gel process. The structural properties of Y2O3：Er^3＋ films were characterized with X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The results indicated that the Y2O3：Er^3＋ films might have high upconversion efficiency because of their low vibrational energy. Under 785 and 980 nm laser excitation, the samples showed green （^2H11/2→^4I15/2, ^4S3/2→^4I15/2） and red （^4F9/2→^4I15/2） upconversion emissions. The upconversion mechanisms were studied in detail through laser power dependence. Excited state absorption and energy transfer process were discussed as possible upconversion mechanisms. The cross relaxation process in Er^3＋ was also investigated.

Preparation and Characterization of Sol-Gel Derived Au Nanoparticle Dispersed Y_2O_3∶Eu Films

Gold nanoparticles dispersed Y2O3 films were prepared through a sol-gel method by using yttrium acetate and Au nanoparticles colloid as precursors. The films were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM） and UV-VIS absorption spectra. XRD patterns and TEM images of Y2O3 ＋ Au films give the same resuits on structure and particle size as that of pure Y2O3 films. The surface plasma resonance （SPR） of Au nanoparticles in Y2O3 ＋ Au film was observed around 550 nm in the absorption spectrum and its position shifts to red with increasing annealing temperature is caused by the increase of dielectric constant of Y2O3 matrix and the size of Au nanoparticles. The second and third order nonlinear optical effects of Y2O3 ＋ Au films were also observed. The photoluminescent properties of Y2O3 ： Eu ＋ Au films were investigated and results indicate that there exist an energy transfer from Eu^3 ＋ to Au nanoparticles and this energy transfer decreases the emission of Eu^3 ＋ in Y2O3 ： Eu ＋ Au film.

Growth of β-Ga_2O_3 Films on Sapphire by Hydride Vapor Phase Epitaxy

Two-inch Ga_2O_3 films with（ˉ201）-orientation are grown on c-sapphire at 850–1050°C by hydride vapor phase epitaxy. High-resolution x-ray diffraction shows that pure β-Ga_2O_3 with a smooth surface has a higher crystal quality, and the Raman spectra reveal a very small residual strain in β-Ga_2O_3 grown by hydride vapor phase epitaxy compared with bulk single crystal. The optical transmittance is higher than 80% in the visible and near-UV regions, and the optical bandgap energy is calculated to be 4.9 e V.

Synthesis of free-standing Ga_2O_3 films for flexible devices by water etching of Sr_3Al_2O_6 sacrificial layers

Flexible electronic devices have attracted much attention due to their practical and commercial value. Integration of thin films with soft substrate is an effective way to fabricate flexible electronic devices. Ga_2O_3 thin films deposited directly on soft substrates would be amorphous mostly. However, the thickness of the thin film obtained by mechanical exfoliation method is difficult to control and the edge of the film is fragile and easy to be damaged. In this work, we fabricated free-standing Ga_2O_3 thin films using the water-soluble perovskite Sr_3Al_2O_6 as a sacrificial buffer layer. The obtained Ga_2O_3 thin films were polycrystalline. The thickness and dimension of the films were controllable. A flexible Ga_2O_3solar-blind UV photodetector was fabricated by transferring the free-standing Ga_2O_3 film on a flexible polyethylene terephthalate substrate. The results displayed that the photoelectric performances of the flexible Ga_2O_3 photodetector were not sensitive to bending of the device. The free-standing Ga_2O_3 thin films synthesized through the method described here can be transferred to any substrates or integrated with other thin films to fabricate electronic devices.

Structure and Waveguide Properties of Sol-Gel Derived Gd_2O_3 Films

Pure and rare earth doped gadolinium oxide (Gd 2O 3) waveguide films were prepared by a simple sol-gel process and dip-coating method. Structure of Gd 2O 3 films annealed at different temperature was investigated by X-ray diffraction and transmission electron microscopy. Oriented growth of (400) face of Gd 2O 3 has been observed when the films were deposited on amorphous substrate. The refractive index and thickness of films were determined by m-lines spectroscopy. The laser beam (λ=632.8 nm) was coupled into the film by a prism coupler and the propagation length is about 3.5 cm. Luminescence properties of europium ions doped films were measured by waveguide fluorescence spectroscopy, which shows disordered environment for Eu 3+ at 400 ℃.

Effect of Al_2O_3 Buffer Layers on the Properties of Sputtered VO_2 Thin Films

VO_2 thin films were grown on silicon substrates using Al_2O_3 thin films as the buffer layers. Compared with direct deposition on silicon, VO_2 thin films deposited on Al_2O_3 buffer layers experience a significant improvement in their microstructures and physical properties. By optimizing the growth conditions, the resistance of VO_2 thin films can change by four orders of magnitude with a reduced thermal hysteresis of 4 °C at the phase transition temperature. The electrically driven phase transformation was measured in Pt/Si/Al_2O_3/VO_2/Au heterostructures. The introduction of a buffer layer reduces the leakage current and Joule heating during electrically driven phase transitions. The C–V measurement result indicates that the phase transformation of VO_2 thin films can be induced by an electrical field.