多层薄膜光学常数的椭偏法研究

研究了椭偏测量中多层薄膜拟和模型建立的过程,并对一未知多层光学薄膜进行了椭偏分析,建立了substrate/film1/EMA/film2/srough的物理结构模型.采用椭偏法,在首先确定出基底光学常数的基础上,提出了从单层、双层、三层逐次建模拟和的分析方法.研究结果表明:对于透明或弱吸收光学薄膜,采用柯西公式可以较好表征材料的色散关系.椭偏分析最终得到的未知薄膜基本结构为G(1.52)/2.0312(203.0 nm)1.4636(170.1 nm)2.079 1(170.4 nm)/A,膜系设计及分光光度计测量的透射光谱证实了这一结果.对多层膜厚度和光学常数的分析表明,椭偏法仍然是一种行之有效的薄膜光学常数测量方法.     

Ba0.9Sr0.1TiO3薄膜的椭偏光谱研究

用椭偏光谱仪首次在光子能量为2.15.2eV的范围内,测量了不同热处理温度下Ba0.9Sr0.1TiO3(BST)薄膜的椭偏光谱.建立适当的拟合模型,并用Cauchy色散模型描述BST薄膜的光学性质,用最优化法获得了所有样品的光学常数(折射率n和消光系数k)谱及禁带能Eg.比较这些结果,初步得到了BST薄膜的折射率n、消光系数k和禁带能Eg随退火温度变化的变化规律.     

纳米尺度HfO_2薄膜的光谱椭偏模型建立

为了建立厚度为1 nm左右HfO_2超薄膜的光谱椭偏测量方法,采用掠入射X射线反射技术进行国家/地区实验室间比对认证,其膜厚准确量值作为参比值,建立了HfO_2超薄膜的光谱椭偏结构拟合模型。研究了HfO_2超薄膜的光谱椭偏色散模型和拟合参数,最后确定了拟合色散模型为Tauc-Lorentz 3,拟合光谱范围为3.45~4.35 eV,表面污染层孔隙比例为60:40。     

Ba_(0.9)Sr_(0.1)TiO_3薄膜的椭偏光谱研究

用椭偏光谱仪首次在光子能量为２．１～５．２ｅＶ的范围内,测量了不同热处理温度下Ｂａ０．９Ｓｒ０．１ＴｉＯ３（ＢＳＴ）薄膜的椭偏光谱,建立适当的拟合模型,并用Ｃａｕｃｈｙ色散模型描述ＢＳＴ薄膜的光学性质,用最优化法获得了所有样品的光学常数（折射率η和消光系数κ）谱及禁带能Ｅｇ．比较这些结果,初步得到了ＢＳＴ薄膜的折射率η、消光系数κ和禁带能Ｅｇ随退火温度变化的变化规律．     

(1-x)TiO_2-xTa_2O_5薄膜的光学性能研究

TiO2-Ta2O5薄膜是较新颖的光学薄膜,由均匀混合的两种化合物薄膜材料作为膜料研制而成,本文采用离子辅助蒸发的方法,以不同配比的Ta2O5和TiO2混合物为初始膜料在K9玻璃上制备了TiO2-Ta2O5混合薄膜,并对其光学性能进行研究.实验结果表明,TiO2-Ta2O5薄膜在可见光范围内有较高的透射率,消光系数在10-3～10-4数量级,折射率在1.80～2.07范围内变化(550nm),是理想的光学镀膜材料.随着Ta2O5含量从0增加到20%,光学带隙从3.266eV单调增加到3.417eV,并用Kayanuma提出的模型解释了透射谱中吸收边的漂移现象.     

X射线反射法和椭圆偏振法结合测量热处理溶胶-凝胶ZrO2薄膜的结构和光学参数

采用溶胶-凝胶法在硅片基底上制备ZrO2薄膜,在150℃～750℃范围内不同温度下进行热处理,研究了热处理对膜层结构和光学性能的影响。X射线反射用于膜层厚度和界面粗糙度分析,结果表明热处理温度由150℃升至750℃,膜层厚度由常温状态下的112.3nm减小到34.0nm,表面和界面粗糙度均小于2nm。以X射线反射法测得的膜层厚度为初始值,对椭圆偏振仪的测量结果进行拟合,得到不同温度的膜层折射率,结果表明热处理温度为550℃时膜层折射率达到最大值。X射线反射作为直接的膜层厚度测试手段,所得结果为准确分析椭偏光谱提供了参考。     

纳米Si薄膜光学性质和弹性常数的研究

采用基于密度泛函理论的第一性原理的方法,对厚度为0.54～3.30nm纳米Si薄膜的电子结构、光学性质及弹性常数进行了计算。结果表明,纳米Si薄膜是直接带隙半导体材料;随着纳米Si薄膜厚度的减小,带隙逐渐增大;薄膜的光学吸收边发生蓝移,吸收带出现宽化现象;弹性常数、杨氏模量和泊松比呈现尺寸效应。     

Surface Effects of the HgI(2) Crystal Characterized by Spectroscopic Ellipsometry

We report on determination of the surface effects of mercuric iodide (HgI(2)) uniaxial HgI(2) optical parameters with a fixed-polarizer, rotating-polarizer, and fixed-analyzer spectroscopic ellipsometer (PRPSE) after chemical polishing. The characteristics of the chemical complex [KHgI(3), H(2)O] that forms on the HgI(2) surface during KI etching have been investigated over the spectral range from 400 to 800 nm. Surface roughness and effects of the ellipsometric parameters of HgI(2) were treated, and the thickness of the layer formed on the surface was determined and analyzed by PRPSE. The surface roughness was modeled with the Bruggeman effective medium approximation.     

Dynamic Adsorption of Albumin on Nanostructured TiO(2)Thin Films

Spectroscopic ellipsometry was used to characterize the optical properties of thin (<5 nm) films of nanostructured titanium dioxide (TiO(2)). These films were then used to investigate the dynamic adsorption of bovine serum albumin (BSA, a model protein), as a function of protein concentration, pH, and ionic strength. Experimental results were analyzed by an optical model and revealed that hydrophobic interactions were the main driving force behind the adsorption process, resulting in up to 3.5 mg/m(2) of albumin adsorbed to nanostructured TiO(2). The measured thickness of the adsorbed BSA layer (less than 4 nm) supports the possibility that spreading of the protein molecules on the material surface occurred. Conformational changes of adsorbed proteins are important because they may subsequently lead to either accessibility or inaccessibility of bioactive sites which are ligands for cell interaction and function relevant to physiology and pathology.     

Determination and Improvement of Deposition Parameters of TiO2 Thin Films via ALD

In recent years,with the development of technology,interest in microelectronics and thin film devices has increased considerably.Future improvements in microele...     

Measurement of the Thickness and Refractive Index of Very Thin Films and the Optical Properties of Surfaces by Ellipsometry

The use of the ellipsometer for the measurement of the thickness and refractive index of very thin films is reviewed. The Poincaré sphere representation of the state of polarization of light is developed and used to describe the reflection process. Details of the operation of the ellipsometer are examined critically. A computational method is presented by which the thickness of a film of known refractive index on a reflecting substrate of known optical constants may be calculated directly from the ellipsometer readings. A method for computing both the refractive index and thickness of an unknown film is also developed. These methods have been applied to the determination of the thickness of an adsorbed water layer on chromium ferrotype plates and on gold surfaces. In the former case the thickness was 23 to 27 Å, and in the latter was 2 to 5 Å. The measurement of the thickness and refractive index of barium fluoride films evaporated on chromium ferrotype surfaces is used as an illustration of the simultaneous determination of these two quantities.     

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.     

光刻胶光学性质的光谱椭偏测量方法研究

利用相调制型光谱椭偏仪研究了光刻胶光学常数的测量方法,针对测量过程中光刻胶曝光控制优化了测量方案和仪器参数。对常见的S9912正型光刻胶,给出了曝光前后275～650 nm波段的光学常数。并采用动态椭偏法测量了所需波长下曝光前的光学常数。实验结果表明:该测量方法适用于光刻胶在紫外-可见-红外宽波段的光学性质研究,在光刻模拟、新型光刻胶材料研制及其光学性质表征等领域有重要实用价值。     

TiO2薄膜的制备方法及应用

TiO2薄膜具有良好的电学性能，优异的光学性能，化学稳定性高，机械强度高，长期以来受到人们的关注，已经广泛应用在电子、光学、医学等方面，本文简单介绍了TiO2薄膜的研备方法及应用。     

TiO2薄膜的结构和光催化活性研究

薄膜型的TiO2光催化剂克服了悬浮型的许多缺点,具有广阔的应用前景.阐述TiO2的结构及其影响因素;评述了晶型、晶粒尺寸、结晶度和晶格缺陷、表面积和表面预处理、表面羟基、温度、薄膜厚度、基体、光源及光强等因素对TiO2薄膜光催化活性的影响;探讨了提高TiO2薄膜光催化活性的措施,包括掺杂、贵金属沉积、半导体复合、表面光敏化等.指出需进一步研究的问题:加强影响因素的综合研究,探索最佳的工艺条件和反应条件;进一步提高TiO2薄膜的光催化效率;将光源种类从紫外光扩展到可见光;将TiO2薄膜的光催化性能同其它性能结合起来研究.     

磁控溅射制备纳米TiO2薄膜导电性的研究

研究了在纳米厚度范围内,TiO₂薄膜的导电性与薄膜厚度和基底材料的关系.利用射频磁控溅射方法,使用高纯Ti(99.99％)靶,通入Ar和O₂的混合气体,制备了TiO₂薄膜,薄膜膜厚15～225nm.在室温下测量了不同厚度TiO₂薄膜的电阻率,发现TiO₂薄膜的导电性,先后在导体、半导体和绝缘体范围变化.这归因于基底材料与TiO₂的功函数不同,导致了界面电子的转移,功函数差决定了电子转移的深度.     

溅射法制备TiO2薄膜的耐腐蚀性

采用溅射法在石英和316L不锈钢衬底上制备TiO2薄膜。采用X射线衍射仪(XRD)、扫描电镜(SEM)、原子力显微镜(AFM)观察薄膜的微观结构和表面形貌。结果表明:沉积后的TiO2薄膜表面均匀、致密,为锐钛矿结构。600℃退火后,薄膜中有金红石相生成。基于透射谱,计算得到的薄膜光学带隙在3.2eV左右。在PBS模拟体液中,测试材料的动电位极化曲线。结果显示,沉积TiO2薄膜后,材料的耐腐蚀性得到改善。退火后,TiO2薄膜的自腐蚀电位正向移动94mV,自腐蚀电流最小,为4.828μA·cm-2。     

磁控溅射制备TiO2薄膜的抗凝血性能

用射频磁控溅射法在生物玻璃基片上沉积TiO2薄膜.通过研究基片温度和热处理对薄膜表面抗凝血性能的影响,比较了基片沉积薄膜前后抗凝血性能的变化,结果发现,在基片温度为500℃制得的TiO2薄膜的抗凝血性能较好,而导致薄膜表面抗凝血性能变化的主要原因在于薄膜表面能、表面结构和形貌的变化.