纳米TiO2薄膜的低温烧结制备及表征

采用改进的溶胶-凝胶法令TiO2在普通玻璃载玻片表面浸渍提拉成膜,再经150℃热处理15min.用阶梯厚度仪、XRD、SEM、XPS、AFM、UV-vis吸收光谱和降解亚甲基蓝实验对所成薄膜的厚度、晶粒大小、表面形貌、吸光性和光催化性能进行了表征.研究结果表明:薄膜为类微晶玻璃态,其纳米粒子晶型为单一锐钛矿型,粒径在10～50nm,薄膜表面均匀、致密,具有良好紫外-可见吸收性和光催化活性.     

纳米TiO2薄膜的低温制备与光谱特性研究

以钛酸丁酯为原料,采用改进溶胶-凝胶法,通过浸渍-提拉工艺在低温条件下制备了锐钛矿纳米TiO2薄膜。利用X射线衍射、紫外-可见光吸收光谱、傅里叶变换红外光谱对所制备的TiO2薄膜的晶型结构和光谱特性进行了分析,并利用紫外光照降解亚甲基蓝溶液来评价所制备薄膜的光催化活性。结果表明:经过陈化和水浴处理后,钛酸丁酯完全水解,所得TiO2薄膜为锐钛矿结构,对紫外光表现出较强的吸收特性。低温水浴处理有利于提高薄膜的光催化活性。     

Morphological characterization of TiO2 thin films

Films prepared by reactive magnetron sputtering always present some structural and morphological heterogeneities.In this work, optical parameters, n(λ), k(λ) and E₀, of TiO₂ thin films were obtained, using only optical transmittance measurements. Films were described according to Abèles's model. Using a mono-oscillator type dispersion curve for the refractive index and a Lorentzian type curve for the absorption coefficient, we were able to demonstrate that the films were optically equivalent to a porous layer, with some dispersion in film thickness.The detailed analysis of the experimental transmittance data, fitted between 330 nm to 2200 nm, also enabled us to correlate the effective refractive index of each film with its deposition conditions.     

Fabrication of micro-patterned TiO2 thin films incorporating Ag nanoparticles

A photosensitive TiO₂ thin film embedded with Ag nanoparticles has been prepared from a Ti(OBu)₄–acetylacetone solution, containing dispersed Ag nanoparticles, by the sol–gel method. UV–visible absorption spectra showed that the thin film obtained has two absorption bands, characteristic of the acetylacetone chelate rings and plasmon resonance from Ag nanoparticles. After the irradiation of UV light, the absorption band from the chelate rings almost disappeared, ascribed to structural changes associated with dissociation of the chelate rings. The thin film after the UV irradiation exhibited a broad absorption band in the IR spectrum, indicating that a Ti–O–Ti network was formed in the thin film. HRTEM and EDX spectra revealed that Ag nanoparticles were present and dispersed in the TiO₂ thin film. Micro-patterns of 50 μm dots have been fabricated by UV irradiation through a corresponding photomask, followed by leaching.     

Room temperature ferromagnetism in Co-incorporated TiO2 thin films

Observation of room temperature ferromagnetism (RTFM) in nano-crystalline Co-incorporated titanium dioxide [Ti(1-x)Co(x)O2(x = 0.05)] thin films prepared by spray pyrolysis technique is reported. While only the anatase phase was detected in as-deposited 5 at.% Co-incorporated TiO2 film, a small amount of rutile phase developed following its vacuum annealing. Besides, no X-ray diffraction peak corresponding to cobalt metal could be detected in any of the two films. SQUID magnetometry of both pristine and Co-doped thin films at room temperature elucidated distinct ferromagnetic behavior in 5 at.% Co-incorporated as-deposited film with saturation moment M(s) approximately 5.6 emu/cm3 which got enhanced up to 11.8 emu/cm3 on subsequent vacuum annealing. From the zero field cooled magnetization measurement we confirmed the absence of Co-metal clusters. The electrical resistivity was found to be greater than 108 omega-cm for the films. Based on the magnetic and electrical measurements the origin of RTFM has been attributed to the bound magnetic polaron (BMP) model.     

微波等离子体低温制备氮杂二氧化钒薄膜

选用V2O5为前驱物,通过在玻璃片上镀膜,采用微波等离子体增强法,在低温条件下,成功制备了氮杂二氧化钒薄膜.通过X射线衍射(XRD),FT-IR对样品进行表征,结果表明:合成的样品为多晶氮杂二氧化钒.相变温度测试结果表明:退火工艺可以降低相变温度,同时提高薄膜的结晶度;改变氮气流量,相变温度先降低后升高,当氮气流量为20ml/min时,相变温度可以降低至40℃.     

Synthesis and characterization of boron-oxygen-hydrogen thin films at low temperatures

We have studied the influence of synthesis temperature on chemical composition and mechanical properties of X-ray amorphous boron-oxygen-hydrogen (B-O-H) films. These B-O-H films have been synthesized by RF sputtering of a B-target in an Ar atmosphere. Upon increasing the synthesis temperature from room temperature to 550 °C, the O/B and H/B ratios decrease from 0.73 to 0.15 and 0.28 to 0.07, respectively, as determined by elastic recoil detection analysis. It is reasonable to assume that potential sources of O and H are residual gas and laboratory atmosphere. The elastic modulus, as measured by nanoindentation, increases from 93 to 214 GPa, as the O/B and H/B ratios decreases within the range probed. Hence, we have shown that the effect of impurity incorporation on the elastic properties is extensive and that the magnitude of the incorporation is a strong function of the substrate temperature.     

Fabrication of low resistive CdS thin films

Low resistive and high mobility thin films of CdS have been grown using vacuum evaporation techniques. X-ray diffraction studies show that the films are well oriented with a preferential growth of crystallites in the (002) plane. The value of conductivity observed in these films is in the range 0.088Ω^-1 cm^-1−1.34Ω^-1 cm^-1 at 300 K.     

以CuCl纳米棒薄膜为前驱体制备CuS纳米/微米管和CuO纳米/微米晶薄膜

在本文中,以由氯化亚铜纳米棒组成的薄膜为前驱体,分别通过气-固相的硫化和氧化反应获得了由直径150到200纳米,长度达数微米的硫化铜管组成的薄膜和粒径为150到200纳米的氧化铜纳米/微米晶所组成的薄膜.利用XRD,SEM,TEM测试方法对薄膜的晶化度,纯度,形貌及结构特点进行了分析.制备的薄膜具有大尺寸,高比表面积,构筑单元为单晶的特点.研究表明,硫化铜纳米/微米管是通过克肯达尔效应形成的,而氧化铜纳米/微米晶是氯化亚铜与空气反应通过类似于化学气相沉积过程形成的.     

Fabrication and characterization of photoelectrode thin films with different morphologies of TiO2 nanoparticles for dye-sensitized solar cells

This study deals with the fabrication of three different morphologies of TiO2 nanoparticles to fabricate two-layer photoelectrode thin film for dye-sensitized solar cells (DSSC). The four different TiO2 morphologies are titania nanotubes (Tnt), TiO2 nanoparticles (H220), TiO2 nanoparticle (SP) and commercial DP-25 nanoparticles (P-25). To prepare the thin films of the photoelectrodes, the first layer is coated by H220 TiO2 nanoparticles, and the second is coated by 3 kinds of materials optimally proportionally mixed - P25, SP and Tnt. The photoelectric conversion efficiency of DSSCs with photoelectrodes fabricated using H220 reached 6.31%. Finally, the TiO2 nanaomaterials with four different morphologies were used to prepare a two layer photoelectrode with the structure of H220/P25-Tnt-SP which was combined with a Pt counter electrode to assemble DSSCs. These DSSCs had photoelectric conversion efficiencies of as high as 7.47%.     

Synthesis of photocatalytic TiO2 thin films via the high-pressure crystallization process at low temperatures

TiO2 thin films with a monophasic anatase structure were synthesized via a high-pressure crystallization (HPC) process which successfully lowered the crystallization temperature of TiO2 films from 350 to 150 degrees C. The thermal budget and energy consumption during the crystallization process were markedly reduced and dense films without cracks were obtained. During the HPC process, crystallization took place throughout the films and TiO2 films with uniform crystallinity were obtained. The HPC process also led to an enhancement in the wettability of TiO2 thin films. The hydrophilicity of the films increased with heating temperatures via high-pressure annealing. In comparison with the conventional annealing, the HPC process not only produced TiO2 films with superior photo-induced super-hydrophilicity, but also led to higher photocatalytic activity of the films. The HPC process was confirmed to provide a new route for synthesizing well-crystallized anatase TiO2 thin films with high photocatalytic activity and good wettability at low temperatures.     

Preparation and characterization of radio-frequency-sputtered Ba2Si2TiO8 thin films

Radio-frequency-sputtered barium titanium silicate (BST, Ba₂Si₂TiO₈) thin films were grown on crystalline Si (100) substrates and were characterized using wavelength-dispersive spectrometry (WDS), X-ray diffraction (XRD), optical microscopy (OM) and scanning electron microscopy (SEM), and diagonal techniques for dielectric properties. The chemical compositions of the films increasingly deviated from stoichiometry with film thickness. At the initial stage of deposition the grain configuration is dependent on the Si substrate texture. XRD analysis indicates that the BST films deposited at an optimum substrate temperature of 845 °C were strongly c-axis oriented, and that the film orientation is manipulated by substrate temperature and supersaturation. The corresponding film-growth rate in the direction normal to the film surface at 845 °C was 1.95 nm min^–1 at the initial stage, and decreased with sputtering time. The as-deposited films have a room-temperature bulk resistivity of 1.8 ×10⁷ m in the direction of thickness and an isotropic surface resistivity of 1.5×10³ m. The high-frequency relative dielectric constant, 0.05 at frequencies higher than 9 MHz, is lower than that of many typical piezoelectric materials. The high-frequency impedance character is typical of piezoelectric materials, giving a minimum impedance frequency of 9.0 MHz and a serial resonant frequency at about 9.5 MHz.     

薄膜厚度和退火温度对纳米多晶硅薄膜特性影响

以高纯SiH4为气源,采用低压化学气相沉积方法在p型〈100〉晶向单晶硅上620℃制备纳米多晶硅薄膜,对不同薄膜厚度纳米多晶硅薄膜分别在700、800、900℃进行高温真空退火,通过X射线衍射(XRD)、Raman光谱(Raman)、场发射扫描电子显微镜(SEM)和原子力显微镜(AFM)研究薄膜厚度、退火温度对薄膜结晶取向、表面形貌等结构特性影响。结果表明,随薄膜厚度增加,薄膜取向显著且多晶特征明显,沉积薄膜多晶取向为〈111〉、〈220〉和〈311〉晶向,择优取向为〈111〉晶向,TO模强度减弱且加宽,晶粒大小增加;同一薄膜厚度,随真空退火温度升高,X射线衍射峰强度增强,TO模强度增强。     

Preparation and characterization of TiO2 thin films by the sol-gel process

Titanium dioxide (TiO₂) thin films have been prepared on microscope slide by the sol-gel process. The preparation of covering solution is investigated with the method of orthogonal experimental design, and the heat treatment temperature and time, which influenced on the films properties are discussed. And the TiO₂ thin films had been studied by the means of differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM).     

大规模真空蒸镀二氧化钛薄膜及其表征

采用大型真空镀膜设备在玻璃基底上蒸镀二氧化钛(TiO2)薄膜,并对TiO2薄膜进行了SEM、AFM、XRD、紫外可见光吸收光谱、亲水性的测试及分析,探讨了退火温度对薄膜性能的影响.结果表明制备的TiO2薄膜具有良好的均匀性.在室温条件下,TiO2薄膜具有无定型的结构;在300～500℃的条件下,TiO2薄膜退火2h后以锐铁矿晶型为主,600℃退火的TiO2薄膜明显向金红石型转变.随退火温度的升高,薄膜对紫外光和可见光的吸收有明显提高,并出现了明显的红移现象.另外,亲水性也随退火温度的升高而变强,500和600℃退火的TiO2薄膜表面出现超亲水性.     

Fabrication and characterization of polyaniline-znO hybrid nanocomposite thin films

Polyaniline (PANI)-ZnO nanocomposite thin film has been successfully fabricated on glass substrates by using vacuum deposition technique. The as-grown PANI-ZnO nanocomposite thin films have been characterized using X-ray diffraction, Scanning Electron Microscopy, Atomic Force Microscopy, UV-visible spectrophotometer and Fourier Transform Infrared (FTIR) spectroscopy, respectively. X-ray diffraction of as-grown film shows the reflection of ZnO nanoparticles along with a broad peak of PANI. The surface morphology of nanocomposite films has been investigated using scanning electron microscopy and atomic force microscopy. The hypsochromic shift of the UV absorption band corresponding to pi-pi* transition in polymeric chain of PANI and a band at 504 cm(-1) due to ZnO nanoparticles has been observed in the FTIR spectra. The hydrogen bonding between the imine group of PANI and ZnO nanoparticle has been confirmed from the presence of the absorbance band at 1151 cm(-1) in the FTIR spectra of the nanocomposite thin films.     

Fabrication and characterization of vacuum deposited fluorescein thin films

Simple vacuum evaporation technique for deposition of dyes on various solid surfaces has been developed. The method is compatible with conventional solvent-free nanofabrication processing enabling fabrication of nanoscale optoelectronic devices. Thin films of fluorescein were deposited on glass, fluorine-tin-oxide (FTO) coated glass with and without atomically layer deposited (ALD) nanocrystalline 20 nm thick anatase TiO₂ coating. Surface topology, absorption and emission spectra of the films depend on their thickness and the material of supporting substrate. On a smooth glass surface the dye initially forms islands before merging into a uniform layer after 5 to 10 monolayers. On FTO covered glass the absorption spectra are similar to fluorescein solution in ethanol. Absorption spectra on ALD-TiO₂ is red shifted compared to the film deposited on bare FTO. The corresponding emission spectra at λ = 458 nm excitation show various thickness and substrate dependent features, while the emission of films deposited on TiO₂ is quenched due to the effective electron transfer to the semiconductor conduction band.     

Electrical conductivity of copper nanoparticle thin films annealed at low temperature

Copper nanoparticles with a mean diameter of 20 nm were used to prepare electrical conductive films at low temperature. After dispersal in an organic solvent, the copper nanoparticle pastes were coated onto a glass substrate, which was then annealed under various conditions to investigate the effects of various atmospheric conditions, such as air, nitrogen gas or hydrogen gas, as well as different annealing temperatures. Two-step annealing, which first involves oxidation in air followed by reduction, is effective in the preparation of high electrical conductive copper nanoparticle films. The copper nanoparticle films that were calcined in air for 1 h and then hydrogen gas for 1 h at a low temperature of 200 °C showed a low resistivity of 2 × 10^-5 Ω cm.     

氧化钆掺杂纳米氧化铈薄膜的制备与烧结性能研究

以Ce(NO3)3·6H2O和Gd2O3为前驱体,六亚甲基四胺为沉淀剂,通过均相沉淀反应直接合成能长时间稳定悬浮的氧化钆掺杂纳米氧化铈(Ce0.8Gd0.2O1.9,GDC)母液.对合成的前驱粉体进行了XRD、BET、动态光散射等研究,XRD结果表明粉体具有氧化铈的立方萤石结构特征峰,BET结果表明粉体比表面积为68.3m2/g,当量粒径为约12nm,非等温烧结实验结果表明粉体具有良好的烧结活性.用浸渍-提拉法(dip-coating)在多孔NiO-YSZ阳极基底上制备GDC电解质薄膜,并利用场发射扫描电镜对薄膜的烧结行为进行了研究,薄膜在1300℃等温烧结后实现完全致密化.通过薄膜制备过程中制浆与成膜两个步骤的有机结合,探讨一条制备高性能GDC电解质薄膜的新途径.     

Fabrication and characterization of NiCr-based films with high resistivity and low temperature coefficient of resistance

As a metal alloy,NiCr films have a relatively high resistivity and low temperature coefficient of resistance (TCR) and are widely used in electronic components and sensors.However,the resistivity of pure NiCr is insufficient for high-resistance and highly stable film resistors.In this study,a quaternary NiCrAlSi target (47:33:10:10,wt.%) was successfully used to prepare resistor films with resistivities ranging from 1000 to 10 000μΩcm and TCR within±100 ppm/K.An oxygen flow was introduced during...