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。     

溅射法制备TiO2薄膜过程中靶中毒现象的消除及样品表征

用氧脉冲直流反应磁控溅射法，在载玻片衬底上制备了不同初始氧浓度和不同断氧时间％的多晶TiO2纳米薄膜，并对薄膜的厚度、晶体结构及表面形貌进行了研究。研究发现，脉冲式通氧能有效消除靶中毒，将薄膜沉积速率最大提高到3～5nm／min，并且当断氧时间大于30s时，沉积速率在2．5nm／min以上；薄膜的晶体结构和形貌随着氧浓度和断氧时间而变化，在初始氧浓度为30％、断氧时间为30s时，金红石结构样品具有最佳结晶程度，并且薄膜的表面平整、晶粒尺寸分布均匀，而锐钛矿结构的最佳结晶条件是氧浓度30％或50％、断氧时间20s.     

直流电弧等离子体法制备TiO2纳米超细粉

采用直流电弧等离子体法直接制备了晶态的TiO2纳米超细粉,粉体中的晶粒既有锐钛矿结构,也有金红石结构;既有单晶结构的TiO2,也有多晶结构的TiO2.当热处理温度低于600℃时,粉体颗粒的长大较为缓慢,粒径在20nm以下;温度高于700℃时,颗粒迅速长大,锐钛矿向金红石结构的转变明显;当温度达到800℃时,样品转变为单晶结构的金红石型TiO2,颗粒大小在40-120nm之间.     

热处理对溶胶-凝胶TiO2薄膜的晶相转变和性能影响

以钛酸丁酯（TPOT）为有机醇盐前驱体，采用溶胶－凝胶技术制备了TiO2溶胶。为测量方便起见，分别制备了凝胶粉体和薄膜，并对样品进行了不同温度的热处理。X射线衍射（XRD）、椭偏仪和紫外－可见光谱（UV－vis)的测量表明：随热处理温度的升高，TiO2的结构由非晶到锐钛矿再到金红石相转变，400℃为锐钛矿相，600℃开始出现金红石相，800℃完全转变为金红石相；晶粒尺寸随热处理温度的升高而逐渐增大，锐钛矿结构的晶粒尺寸范围是2.5-5.5nm，金红石结构的晶粒尺寸范围是5.9-6.8nm；TiO2薄膜的折射率随热处理温度的升高而增大，同时薄膜厚度降低；禁带宽度随热处理温度的升高而增大，同时薄膜厚度降低；禁带宽度随热处理温度升高而变窄，锐钛矿结构的禁带宽度为3.45eV，而金红石结构的禁带宽度为3.30eV。     

TiO2薄膜的Sol—gel制备及结构分析

以正钛酸丁酯，无水乙醇和冰醋酸为原料，采用Ｓｏｌ－ｇｅｌ工艺匀胶技术在石英玻璃和单晶硅衬底上成功地制备了ＴｉＯ２薄膜，薄膜表面均匀，致密，无裂纹。研究表明，随热处理温度的提高，薄膜经锐钛矿转变为金红石结构，其转变温度因衬底不同而异，但比凝胶粉末的转变温度高，金红石结构的ＴｉＯ２薄膜具有一定的择优取向性，其晶粒大小为０．０５～０．１５μｍ。     

电子墨水用纳米TiO2白色颗粒的制备

以Ti（OC4H9）4为原料，在溶有聚乙烯醇或聚乙烯吡咯烷酮分散剂的溶液中直接水解、胶溶，制备出单分散性、热稳定性良好，平均粒径在500nm的电子墨水用TiO2纳米微粒。研究了Ti（OC4H9）4浓度、水解时间、溶剂加入方式对纳米微粒粒径的影响。对样品进行了TG-DTA，XRD和SEM分析。结果表明：样品经真空干燥后，TiO2粉体主要为无定形胶体，随焙烧时间增加和温度升高，在450℃粉体从无定形向锐钛矿型转变，在900℃保温3h从锐钛矿型向金红石型转变，粉体粒径也有一定增大，1200℃保温3h，仅含有金红石相，粉体为实心球体，表面光滑。     

硅基板上Fe掺杂TiO2氧敏薄膜的制备、结构与性能研究

采用溶胶-凝胶法,以Ti(OC4H9)4为前驱体,用提拉法在硅基板上制备了掺Fe的TiO2氧敏薄膜,对薄膜物相结构进行了X射线衍射(XRD)测定,利用扫描电镜(SEM)对薄膜微结构进行了观察.结果表明在硅基板上生长的TiO2薄膜中锐钛矿相为均匀小晶粒分布结构,金红石相以大尺度团聚结构形貌出现.Fe离子的掺杂对硅基板上制备的TiO2薄膜中金红石相的形成有很大的影响.Fe的掺入降低了金红石相的形成温度约100℃,Fe掺量在6mol%时,形成金红石相的量达到最大,即析晶能力最强.薄膜中形成晶相的晶格常数在＜6mol%的低Fe范围内,随较小的Fe离子取代较大的Ti离子,锐钛矿相和金红石相的晶格常数都随之减小;在＞6mol%的高Fe掺量范围内,随Fe掺量的增加,体系缺陷过量增加,晶格结构畸变严重,伴随着畸变能的释放,金红石相的晶格常数c轴逐渐增长,a轴略有下降(或基本不变).TiO2氧敏薄膜的氧敏性能受金红石相含量和氧空位浓度控制.当Fe离子掺杂浓度为6mol%时,金红石相及相应氧空位达到最大值,TiO2氧敏薄膜的氧敏性能也达到最大值,比刚形成金红石相的薄膜的氧敏性能增加近19倍.     

水热法制备的Ti1-xCoxO2稀磁半导体特性

采用水热法制备出Ti1-xCoxO2(x=0～0.10)稀磁半导体材料,并对其形貌、结构及磁性能进行表征.X射线衍射分析结果表明,纯TiO2样品为锐钛矿相,掺杂Co离子后样品中出现金红石相,当掺杂浓度到0.10时样品中出现Co3O4的衍射峰.透射电镜和X射线能量色散谱测试结果表明,样品形貌规整,平均粒径约为20nm,并且证实样品中含有Co元素.利用振动样品磁强计对其磁性进行测量,结果表明样品在室温条件下存在铁磁性.     

金红石型二氧化钛超微颗粒制备及表征

以偏钛酸为原料制备TiO2 ,超微颗粒 ,利用XRD、TG -DTA、TEM测试等手段测试样品的形态结构。结果表明 ,水合TiO2 为金红石相结构 ,经 5 0 0℃煅烧样品粒径为 10～ 2 0nm ,大小分布均匀。     

直流反应磁控溅射制备二氧化钛薄膜的光催化性研究

在磁控溅射器中用钛板作阴极 ,采用直流反应磁控溅射在玻璃基板上制备二氧化钛薄膜 ,溅射气体为氧、氩混合气体 ,O2 与Ar比例为 1∶2 ,溅射总气压范围为 0 5～ 6 65Pa ,溅射时基板温度范围为 1 0 0～ 40 0℃ ,薄膜厚度范围为 1 4 0～ 1 1 0 0nm。XRD结果显示薄膜具有纯锐钛矿结构或锐钛矿和金红石的混合结构。在高的基板温度和适宜的溅射总气压下制备的薄膜以及厚度较厚的薄膜在紫外光照射后 ,有较好的光催化性     

A study of structural transition in nanocrystalline titania thin films by X-ray diffraction Rietveld method

Structural and microstructural analyses of nanocrystalline titania thin films prepared by pulsed laser deposition have been carried out. At lower oxygen partial pressures (≤10⁻⁴ mbar), rutile films were formed, whereas at 1.2 × 10⁻³ mbar of oxygen partial pressure, the thin films contained both rutile and anatase phases. At 0.04 and 0.05 mbar of oxygen partial pressure, the film was purely anatase. Addition of oxygen has also shown a profound influence on the surface morphology of the as deposited titania films. Modified Rietveld method has been used to determine crystallite size, root mean square strain and fractional coordinates of oxygen of the anatase films. The influence of crystallite size and strain on the rutile to anatase phase transition is investigated.     

纳米TiO2薄膜的脉冲激光沉积及其光学特性

采用脉冲激光沉积技术(PLD)在硅基片上生长了二氧化钛纳米晶氧化物薄膜, 系统讨论了基片温度、氧分压等因素对薄膜结构特性的影响.X射线衍射结果表明在氧气氛下, 生长的薄膜为锐钛矿结构, 其结晶性随着基片温度的升高而增强, 在750℃、5Pa氧压的情况下为完全c轴取向的锐钛矿相TiO₂薄膜, 在750℃、5Pa氩气氛下则为(110)取向的金红石相薄膜. 场发射扫描电子显微镜结果表明薄膜表面致密, 呈纳米晶结构, 其晶粒尺寸在35nm左右.用傅立叶红外光谱和拉曼光谱对不同条件下制备的TiO₂薄膜进行了表征.紫外-可见透射光谱的测试结果表明, 薄膜在可见光区具有良好的透过率, 计算得到制备的锐钛矿和金红石相TiO₂薄膜在550nm处的折射率分别为2.3和2.5, 其光学带隙分别为3.2和3.0eV.因此通过沉积条件的改变可得到结晶性能和光学性能都不同的TiO₂薄膜.     

Etch damage characteristics of TiO2 thin films by capacitively coupled RF Ar plasmas

Etch damage of TiO₂ thin films with the anatase phase by capacitively coupled RF Ar plasmas has been investigated. The plasma etching causes a mixed phase of anatase and rutile or the rutile phase. The effect of Ar plasma etching damage on degenerating TiO₂ thin films is dependent on gas pressure and etching time. The physical etching effect at a low gas pressure (1.3 Pa) contributes to the degradation: the atomic O concentration at the thin film surface is strongly increased. At a high gas pressure (13-27 Pa) and long etching time (60 min), there are a variety of surface defects or pits, which seem to be similar to those for GaN resulting from synergy effect between particle and UV radiation from the plasmas. For the hydrophilicity, the thin film etched at the high gas pressure and a short etching time (5 min) seems to have no etch damage: its contact angle property is almost similar to that for the as-grown thin film, and is independent of the black light irradiation. This result would probably result from formation of donor-like surface defects such as oxygen vacancy.     

Structural and mechanical properties of titanium oxide thin films for biomedical application

Titanium oxide thin films were deposited by radiofrequency reactive sputtering in Ar-O₂ atmosphere on silicon (100) wafers and titanium alloy plates (Ti-6Al-4V). Thin films structural characterization was carried out by grazing incidence X-ray diffraction, atomic force microscopy, scanning and transmission electron microscopies. Chemical composition was checked by X-ray wavelength dispersive spectroscopy. Mechanical assessment was achieved by nano-indentation and nano-scratch measurements. The films deposited on silicon substrates are over-stoechiometric in oxygen, with an oxygen to titanium ratio of about 2.2. The growth of anatase and rutile phases was promoted by ranging the total and oxygen partial pressures between 0.17-1.47 Pa and 35-85%. The growth rate of films, determined by grazing incidence X-ray reflectivity, was ranging from 35 to 55 nm/h. The rutile single-phased films possess a hardness of about 2.5 times higher and a lower friction coefficient than the anatase films. The films which contain anatase possess a high surface root-mean-square roughness and a reduced elastic modulus of around 120 GPa close to reduced elastic moduli of hydroxyapatite bioceramic and titanium alloy. So the anatase film could be the best candidate as a titanium oxide intermediate layer between hydroxyapatite and titanium alloy in the field of biomedical implants.     

硅基板上Fe掺杂TiO2氧敏薄膜的制备、结构与性能研究

采用溶胶-凝胶法,以Ti(OC₄H₉)₄为前驱体,用提拉法在硅基板上制备了掺Fe的TiO₂氧敏薄膜,对薄膜物相结构进行了X射线衍射(XRD)测定,利用扫描电镜(SEM)对薄膜微结构进行了观察.结果表明:在硅基板上生长的TiO₂薄膜中锐钛矿相为均匀小晶粒分布结构,金红石相以大尺度团聚结构形貌出现.Fe离子的掺杂对硅基板上制备的TiO₂薄膜中金红石相的形成有很大的影响.Fe的掺入降低了金红石相的形成温度约100℃,Fe掺量在6mol% 时,形成金红石相的量达到最大,即析晶能力最强.薄膜中形成晶相的晶格常数在<6mol%的低Fe范围内,随较小的Fe离子取代较大的Ti离子,锐钛矿相和金红石相的晶格常数都随之减小;在>6mol%的高Fe掺量范围内,随Fe掺量的增加,体系缺陷过量增加,晶格结构畸变严重,伴随着畸变能的释放,金红石相的晶格常数c轴逐渐增长,n轴略有下降(或基本不变). TiO₂氧敏薄膜的氧敏性能受金红石相含量和氧空位浓度控制.当Fe离子掺杂浓度为6mol% 时,金红石相及相应氧空位达到最大值,TiO₂氧敏薄膜的氧敏性能也达到最大值,比刚形成金红石相的薄膜的氧敏性能增加近19倍.     

Pulsed laser deposition of titania on rutile nanorod arrays

Oriented rutile nanorod arrays are precipitated on metallic Ti plates from a precursor derived by interactions between Ti and aqueous hydrogen peroxide. Pulsed laser deposition (PLD) is then carried out to deposit titania on the nanorod arrays, in comparison with bare Ti substrates, utilizing a high-temperature sintered rutile target in oxygen atmosphere. It is found that dense and homogeneous titania thin films are obtained on Ti substrates; while growth on the rutile nanorod arrays is epitaxial, resulting in enlarged nanorods conformally covered with titania. Titania grown on both Ti substrates and rutile nanorod arrays is either pure rutile or a mixture of anatase and rutile, with the formation of anatase favored by an increasing oxygen pressure during the PLD procedure. The surface roughness and the particle size of the dense titania films on Ti substrates increase as a result of increasing oxygen pressure and prolonged deposition time. The PLD-induced epitaxial growth of titania is inhibited by increasing substrate temperatures. The photocatalytic experiments reveal a significantly enhanced activity for the rutile nanorod arrays after a subsequent PLD treatment.     

Nanosecond pulsed laser deposition of TiO2: nanostructure and morphology of deposits and plasma diagnosis

Nanostructured TiO₂ films on Si (100) substrates have been grown by nanosecond pulsed laser deposition at the wavelengths of 266, 355 and 532 nm using a Q-switched Nd:YAG laser and TiO₂ sintered rutile targets. The effect of laser irradiation wavelength, the temperature of the substrate and the presence of O₂ as background gas on the crystallinity and surface structure of deposits were determined, together with the composition, expansion dynamics and thermodynamic parameters of the ablation plume. Deposits were analyzed by X-ray photoelectron spectroscopy, X-ray diffraction, environmental scanning electron microscopy and atomic force microscopy, while in situ monitoring of the plume was carried out and characterized with spectral, temporal and spatial resolution by optical emission spectroscopy. Stoichiometric, crystalline deposits, with nanostructured morphology were obtained at substrate temperatures above 600 °C. Microscopic particulates were found overimposed on the nanostructured films but their size and density were significantly reduced by operating at short wavelength (266 nm) and upon addition of a low pressure of oxygen (0.05 Pa). The dominant crystalline phase is rutile at 355 and 532 nm. At the short irradiation wavelength, 266 nm, the preferred phase in the presence of oxygen is rutile, while anatase is preferably observed under vacuum. The narrowest size distribution and smallest nanoparticle diameters, of around 25 nm, were found by deposition at 266 nm under 0.05 Pa of oxygen.     

TiO2纳米微粒的溶胶-凝胶法制备及XRD分析

本文采用溶胶 凝胶法制备二氧化钛纳米微粒。用XRD分析了二氧化钛胶体经不同温度热处理后的晶粒粒径。分析表明温度在 4 73K时TiO2 微粒呈锐钛矿结构 ,粒径约为 5 5nm。在 6 73K以上TiO2 粒径迅速增大 ,微粒出现锐钛相与金红石相混晶结构。 973K时TiO2 微粒完全转化为金红石相。用晶界结构弛豫的观点解释粒径随热处理温度变化关系     

Anatase-rutile transformation through high-temperature annealing of titania films produced by ultrasonic spray pyrolysis

Titanium dioxide films were prepared by ultrasonic spray pyrolysis on (0001) α-quartz substrates at 400 °C and/or annealed in air at 600°, 800°, or 1000 °C. The as-deposited films at 400 °C (50 nm grains) and annealed at 600 °C (100 nm grains) showed single-phase anatase of high transparency in the visible region. Films annealed at 800 °C and 1000 °C showed mixed-phase anatase (100 nm grains) plus rutile (700 nm agglomerates) and pure rutile, (700 nm grains), respectively. Raman and X-ray data indicate the presence of residual stress in the films, which may arise from contamination, silicon diffusion into the films, and/or oxygen deficiency.     

Micro-Raman spectroscopy study of surface transformations induced by excimer laser irradiation of TiO2

Pressed disks of TiO₂ powder particles (≈1 μm in size) have been irradiated with a pulsed KrF (248 nm) excimer laser source at fluences between 0.1 and 1 J cm⁻². Surface films (1.5–2 μm thick) have been studied by Raman microprobe spectroscopy and atomic force microscopy (AFM). The Raman study reveals a three-layer structure for the irradiated anatase powders. A dark layer of reduced oxide is sandwiched between a top coating of molten/resolidified rutile and an underlying defective, slightly oxygen-deficient mixed-phase of rutile and anatase. AFM measurements indicate that a smooth surface layer coexisting with the initial rough grain morphology gradually appears with increasing fluence. At low fluence, anatase is reduced in a dark film and further transformed into rutile. At intermediate fluence, a shiny coating of resolidified stoichiometric rutile forms on the dark film. It gets thicker as the fluence increases while darkening of the sublayer intensifies up to a maximum of approximately 700 mJ cm⁻². At high fluence, however, melting and re-oxidation (and eventually ablation) prevail over reduction; the whole layer turns into a greyish crust of mostly resolidified rutile in non-ablated regions. A physico-chemical mechanism is proposed to explain the in-depth distribution of the various components as a function of fluence.