LPCVD水解法制备TiO2薄膜

本文利用LPCVD法水解四异丙醇钛(TTIP)制备TiO2薄膜，研究了制备过程中水解TTIP的反应动力学。通过对沉积温度和沉积率关系的研究，计算出TTIP水解反应表观活化能为59．85kJ／mo1。沉积温度不仅影响反应速率，还对TO2薄膜结构、表面形貌有决定性的作用。XRD和Raman分析表明：TTIP水解法制备TiO2薄膜，薄膜结构主要依赖于沉积温度。180℃—220℃沉积TiO2薄膜为非晶态，240℃—300℃沉积为锐钛矿和非晶态混杂结构。在水分压对TTIP水解反应影响的研究中发现，水分压为零时，TTIP发生热解反应，TiO2沉积率不为零，热解反应240℃无锐钛矿特征峰出现。这说明水解反应制备TiO2有利于降低锐钛矿的生长温度。氧分子的加入可以消除TiO2薄膜表面的“针孔”。     

电子束蒸发氧化钛薄膜的化学成分与显微结构

用电子束蒸发的方法在Ti盘上沉积氧化钛薄膜。分别用场发射扫描电镜,X射线光电子谱和X射线衍射分析所制备薄膜的表面形貌、化学成分和晶体结构,所制备的氧化钛薄膜的晶体结构依赖于制备过程中的沉积参数,薄膜的成分主要为金红石结构,是包含TiO2,Ti2O3和TiO三种结构的多晶体,随着沉积过程中氧气流量的增加,所制备的薄膜中高价钛离子(如Ti4+)的含量不断增大,同时低价钛离子(如Ti2+)的含量不断减小。随着氧气流量的增加和后续热处理温度的升高,薄膜的结晶度不断增大,并呈现出单一金红石(101)相位的趋势。     

锐钛矿型TiO2薄膜的低温制备及性能研究

采用液相沉积法,在低温下制备TiO2薄膜,研究了制备条件对薄膜中TiO2的晶型、薄膜厚度、透光性、亲水性及光催化活性的影响.结果表明,在90℃下制备的TiO2为锐钛矿型,薄膜的厚度与反应温度、沉积时间、HBO3的加入量及反应物浓度有关,所制备的薄膜具有良好的光诱导超亲水特性和光催化活性,在可见光区的透光率＞80%.     

MOCVD方法在TiO2纳米粉末制备中的应用

众所周知,MOCVD方法是制备薄膜材料的重要方法之一,现已广泛应用于半导体薄膜、铁电薄膜和超导薄膜等的制备.在以前的工作中,我们设计、加工、安装、调试、建立了一套可计算机自动控制的热壁低压MOCVD设备,制备出了TiO2纳米粉末,得到了一些初步结果.本文详细研究了热壁低压MOCVD方法在TiO2纳米粉末制备中的应用,通过合理设计反应室和收集区域,在采用反应区域和收集区域之间无任何过渡区域的收集方式,制备出了TiO2纳米粉末.采用X射线衍射技术研究了沉积温度对TiO2纳米粉末的晶体结构和平均晶粒尺寸的影响规律.在500℃～1000℃范围内,粉末均为锐钛矿结构,平均晶粒尺寸7.4～15.2nm,700℃条件下制备的TiO2纳米粉末的平均晶粒尺寸最小.透射电子显微镜观察表明,在最佳沉积温度700℃条件下制备的TiO2粉末粒度均匀性好,粒径约为5～8nm.     

TiO_2磁控溅射工艺参数对薄膜沉积速率的影响

为了经济、有效、准确地在线测量光学薄膜厚度,采用射频磁控反应溅射法在玻璃衬底上制备TiO2薄膜。用自制的简易监测系统对TiO2薄膜在生长过程中的沉积速率进行了即时测量,研究了射频功率、气体流量、工作气压等工艺参数对TiO2薄膜沉积速率的影响规律。结果表明:沉积速率监测系统对膜厚变化反应灵敏,能够实时监测薄膜生长速率;溅射过程中,射频功率、氧氩流量比和工作气压对薄膜沉积速率有较大的影响,射频功率从120 W增加到240 W,薄膜沉积速率增加;氧气流量从1 mL/min增加到5 mL/min,薄膜沉积速率先逐渐增大后减小,存在一个临界点;工作气压从0.3 Pa增加到0.8 Pa,薄膜沉积速率缓慢增加,但临界点后迅速下降。     

可逆光致变色的Ag@TiO2纳米复合膜（英文）

为了防止活性等离子体对下层银膜的破坏,采用多晶TiO2半导体烧结靶,使用射频磁控溅射方法在纯氩等离子气氛中制备了大面积均匀的TiO2、Ag@TiO2薄膜。为了了解其结构与电子和光学特性间的相互作用,对TiO2和TiO2/Ag/TiO2样品的制备参数(如射频功率、总压和直流电压的共同影响)进行了研究。采用掠入射X射线衍射、紫外可见吸收、拉曼光谱等技术研究了根据其结构调整光学性能的可能性。结果显示,沉积的TiO2薄膜具有与在氩气和氧气混合气氛中沉积所得薄膜相似的形貌、电子和光学特性、能隙带宽和晶相;且所制备的Ag@TiO2薄膜银具有可逆的光致变色特性,可作为智能窗、多波长光存储器和可擦写高密度电子纸使用。     

铝合金表面制备二氧化钛薄膜及其光催化活性研究

分别以阳极氧化处理的6061铝合金和纯铝为载体,用液相沉积的方法在载体上制备了二氧化钛薄膜.结果表明,在6061铝合金上的TiO2纳米薄膜呈现带有孔洞的竹节状结构,而纯铝基片上的TiO2纳米薄膜具有良好的一维贯通结构.这主要是在AAO模板制备过程中,由于铝合金中的合金元素Mg被氧化,其产生的氧化物体积比Al2O3的体积小所致.在铝合金表面的TiO2薄膜光催化性能优于纯铝表面的TiO2薄膜.铝合金表面制备的TiO2薄膜因其特殊的带孔洞的竹节状结构,使其比表面积比纯铝上的TiO2薄膜大,因此其光降解甲基蓝效果更好.TiO2对甲基蓝的光催化降解符合一级反应动力学公式,在0.1 mol/L的氟钛酸铵溶液中沉积得到的TiO2薄膜光催化性能最好,表观反应速率为k=0.00444/min.     

退火温度对TiO2薄膜结构和表面形貌的影响

研究了退火温度对中频交流反应磁控溅射技术制备的TiO2 薄膜结构和表面形貌的影响。利用X射线衍射仪和原子力显微镜 ,检测了TiO2 薄膜的晶体结构和表面形貌。实验结果显示 :沉积态TiO2 薄膜为非晶态 ;低温 (70 0℃以下 )退火后 ,TiO2 薄膜出现锐钛矿相 ,晶粒长大不明显 ;高温退火 (90 0℃以上 )后 ,薄膜转变为金红石相 ,晶粒由柱状转变为棱状 ,并迅速长大至微米量级     

CeO2掺杂TiO2催化剂薄膜的制备与表征

以Ar为工作气体，O2为反应气体，利用射频磁控溅射技术成功地在载玻片上沉积了透明TiO2催化剂薄膜。同时利用共溅射技术制备了掺杂CeO2的TiO2催化剂薄膜。采用X射线衍射(XRD)、Raman光谱、UV-VIS-NIR分光光度计、原子力显微镜(AFM)对薄膜进行了结构和形貌表征。     

浸渍法在玻璃单层上选择沉积TiO2薄膜

以硅烷偶联剂作为表面修饰剂,在大气气氛中于普通载玻片上的有机单层上选择沉积制备出TiO2薄膜.使用差示扫描量热-失重(DSC-TG)分析、X射线衍射(XRD)分别对TiO2薄膜的凝胶前驱体和TiO2粉末进行表征,并对TiO2薄膜进行了X射线荧光光谱(XRF)分析.结果表明,所制备的TiO2薄膜是纳米级的锐钛矿单层膜.     

Photocatalytic TiO(2) deposition by chemical vapor deposition

Dip-coating, spray-coating or spin-coating methods for crystalline thin film deposition require post-annealing process at high temperature. Since chemical vapor deposition (CVD) process is capable of depositing high-quality thin films without post-annealing process for crystallization, CVD method was employed for the deposition of TiO(2) films on window glass substrates. Post-annealing at high temperature required for other deposition methods causes sodium ion diffusion into TiO(2) film from window glass, resulting in the degradation of photocatalytic efficiency. Anatase-structured TiO(2) thin films were deposited on window glass by CVD, and the photocatalytic dissociation rates of benzene with CVD-grown TiO(2) under UV exposure were characterized. As the TiO(2) film deposition temperature was increased, the (112)-preferred orientations were observed in the film. The (112)-preferred orientation of TiO(2) thin film resulted in a columnar structure with a larger surface area for benzene dissociation. Obviously, benzene dissociation rate was maximum when the degree of the (112) preferential orientation was maximum. It is clear that the thin film TiO(2) should be controlled to exhibit the preferred orientation for the optimum photocatalytic reaction rate. CVD method is an alternative for the deposition of photocatalytic TiO(2).     

氧脉冲磁控溅射法制备多晶TiO2薄膜

利用一种改进的溅射方法在载波片上制备了多晶TiO2薄膜。由于该法在溅射过程中氧气控制得像脉冲一样,所以称之为氧脉冲直流磁控反应溅射。它能有效的减轻靶中毒,样品沉积速率达到传统反应溅射法的7倍左右。分别利用椭圆偏振测厚仪、X射线衍射仪和场发射扫描电子显微镜研究了沉积时间、氧分压以及氧气开关时间对沉积速率、晶体结构和表面形貌的影响。研究结果显示,在氧分压为30％,断氧时间Toff=30s和20s下制备的样品具有最好的金红石相或锐钛矿相单一晶体结构,并且在Toff=30s时,具有最佳的表面形貌。此外,在较高沉积速率和较低氧分压下,样品更趋向于生成金红石相。利用范德堡法研究了样品的电阻率,在氧分压为30％,Toff=30s和50％,Toff=40s下制备的样品的电阻率为10·cm左右。该样品适合进一步研究透明导电TiO2薄膜。     

Patterning of TiO2 particles on poly(dimethyl siloxane) films by using proton irradiation and liquid-phase deposition process

Micropatterning of titanium dioxide (TiO2) on the surface of thin poly(dimethyl siloxane) (PDMS) films was described by means of proton irradiation and liquid-phase deposition (LPD) techniques. The surface of thin PDMS films was irradiated with accelerated proton ions through a pattern mask in the absence or presence of oxygen in order to create hydrophilically/hydrophobically patterned surfaces. The results of the surface analysis revealed that the PDMS films irradiated at the fluence of 1 x 10(15) ions cm-2 in the presence of oxygen showed the highest hydrophilicity. The LPD of TiO2 particles on the patterned PDMS film surface showed a selective deposition of TiO2 on the irradiated regions, leading to well defined TiO2 micropatterns. The crystal structure of the formed TiO2 films was found to be in an anatase phase by X-ray diffraction analysis. This process can be applied for patterning various metal and metal oxide particles on a polymer substrate.     

Properties of TiO2 Thin Films Prepared by Magnetron Sputtering

With rapid progressive application of TiO2 thin films,magnetron sputtering becomes a very interesting method to prepare such multi-functional thin films.This paper focuses on influences of various deposition processes and deposition rate on the structures and properties of TiO2 thin films.Anatase,rtile or amorphous TiO2 films with various crystalline structures and different photocatalytic,optical and electrical properties can be produced by varying sputtering gases,substrate temperature,annealing process,deposition rate and the characteristics of magnetron sputtering.This may in turn affect the function of TiO2 films in many applications.Furthermore,TiO2-based composites films can overcome many limitations and improve the properties of TiO2 films.     

Photocatalytic degradation of methyl orange: influence of H2O2 in the TiO2-based system

The purpose of this study was to investigate the photocatalytic oxidation of a reactive azo dye. The photocatalytic activity of the TiO2 was studied using a reactor equipped with UV-A sources, with maximum emission at 365 nm. The photocatalytic activity of the TiO2 powder (99.9% anatase) and thin films has been measured through the decomposition of methyl orange solutions. The thin film was prepared by doctor blade and spray pyrolysis deposition (SPD). The TiO2 suspensions were prepared at 1 g/L concentration, and the initial methyl orange concentration was fixed at 7.8125 mg/L. The influence of the TiO2 (powder or thin films) and/or O2 and H2O2 on the photobleaching rate, was tested under different experiments, at pH = 5. Thin films (doctor blade) of TiO2 formed of mezo-sized aggregates formed of nanosized anatase crystallites show better photobleaching efficiency than thin film (SPD) due to their large internal surface. The rate is even higher in H2O2 compared to oxygen environment.     

Enhancement of crystallinity and optical properties of bilayer TiO2/ZnO thin films prepared by atomic layer deposition

Bilayer and multilayer thin films are becoming increasingly important in the development of faster, smaller and more efficient electronic and optoelectronic devices. One of the motivations of applying bilayer or multilayer structures is to modify the optical properties of materials. Atomic layer deposition (ALD) is a variant of Chemical Vapour Deposition that can produce uniform and conformal thin films with well controlled nanostructures. In this study, we have demonstrated new findings of the use of ALD fabricated bilayer TiO2/ZnO thin films with enhanced crystallinity and optical properties. TiO2 films have been deposited at 300 degrees C for 1000 (51 nm in thickness) or 3000 (161 nm in thickness) deposition cycles onto glass and Si substrates. ZnO films are subsequently deposited on the TiO2 layers at 280 degrees C for 500 deposition cycles (55 nm). The crystallinity and optical properties of the TiO2/ZnO thin films have been analysed by X-ray diffraction, photoluminescence, UV-Vis spectroscopy, Atomic Force Microscopy and Scanning Electron Microscopy. XRD diffraction pattern confirmed the presence of ZnO with wutrtize crystal structure and TiO2 with anatase structure. It shows that the crystallinity of the TiO2 films has been improved with the deposition of ZnO. The intensity of UV luminescence has increased by almost 30% for TiO2/ZnO bilayer as compared to the single layer TiO2. The possible mechanism for the enhancement of the optical properties of bilayer TiO2/ZnO thin films will be discussed.     

Controlling the crystallinity and roughness of atomic layer deposited titanium dioxide films

The surface roughness of thin films is an important parameter related to the sticking behaviour of surfaces in the manufacturing of microelectomechanical systems (MEMS). In this work, TiO2 films made by atomic layer deposition (ALD) with the TiCl4-H2O process were characterized for their growth, roughness and crystallinity as function of deposition temperature (110-300 degrees C), film thickness (up to approximately 100 nm) and substrate (thermal SiO2, RCA-cleaned Si, Al2O3). TiO2 films got rougher with increasing film thickness and to some extent with increasing deposition temperature. The substrate drastically influenced the crystallization behaviour of the film: for films of about 20 nm thickness, on thermal SiO2 and RCA-cleaned Si, anatase TiO2 crystal diameter was about 40 nm, while on Al2O3 surface the diameter was about a micrometer. The roughness could be controlled from 0.2 nm up to several nanometers, which makes the TiO2 films candidates for adhesion engineering in MEMS.     

Effects of reduced chemical vapor deposition environment on growth and optical characteristics of TiO2 nanobelts

TiO2-delta nanobelts were self-catalytically grown at 510 degrees C on bare Si (100) substrates using metallorganic chemical vapor deposition. The nanobelt formation was critically affected by the partial pressure of oxygen. The nanobelts were grown when supplying only Ar or a mixed gas of Ar (90%) and H2 (10%), while thin films were formed with an O2 gas flow of more than 50 cm3 min(-1). The nanobelts consisted of approximately 20-30 nm size rutile-dominant nanocrystallites. A vapor-solid growth mechanism excluding a liquid phase appeared to control the nanobelt formation. The grown TiO2-delta nanobelts showed a strong photoluminescence (PL) spectra peak at approximately 550 nm due to oxygen vacancies. The nanobelt surface possessed significant amount of oxygen vacancies contributing PL and actively reacting with the environment, indicating promise for photocatalytic and gas sensor applications in a visible light regime.     

射频磁控反应溅射制备Al2O3薄膜的工艺研究

采用射频磁控反应溅射法,以高纯Al为靶材,高纯O2为反应气体,在不锈钢和单晶Si基片上成功地制备了氧化铝(Al2O3)薄膜,并对氧化铝薄膜的沉积速率、结构和表面形貌进行了研究.结果表明,沉积速率随着射频功率的增大先几乎呈线性增大而后缓慢增大;随着溅射气压的增加,沉积速率先增大,在一定气压时达到峰值后继续随气压增大而减小,同时随着靶基距的增大而减小;随着氧气流量的不断增加,靶面溅射的物质从金属态过渡到氧化物态,沉积速率也随之不断降低.X射线衍射图谱表明薄膜结构为非晶态;用原子力显微镜对薄膜表面形貌观察,薄膜微结构为柱状.     

Mixed films of TiO(2)-SiO(2) deposited by double electron-beam coevaporation

We used double electron-beam coevaporation to fabricate TiO(2)-SiO(2) mixed films. The deposition process included oxygen partial pressure, substrate temperature, and deposition rate, all of which were real-time computer controlled. The optical properties of the mixed films varied from pure SiO(2) to pure TiO(2) as the composition of the films varied accordingly. X-ray diffraction showed that the mixed films all have amorphous structure with a SiO(2) content of as low as 11%. Atomic force microscopy showed that the mixed film has a smoother surface than pure TiO(2) film because of its amorphous structure.

Linear and Bruggeman's effective medium approximation models fit the experimental data better than other models.