原子层沉积制备Ta_2O_5薄膜的光学特性研究

以乙醇钽[Ta(OC2H5)5]和水蒸气为前驱体,采用原子层沉积(ALD)方法分别在基板温度为250℃和300℃的K9和石英衬底上制备了Ta2O5光学薄膜。采用分光光度计、X射线光电子能谱(XPS)、X射线衍射(XRD)、扫描电子显微镜(SEM)和原子力显微镜(AFM)等手段对薄膜的光学特性、微结构和表面形貌进行了研究。结果表明,用ALD方法制备的Ta2O5薄膜在刚沉积和350℃退火后均为无定形结构,而250℃温度下沉积的薄膜其表面粗糙度低,聚集密度很高,光学均匀性优,在中紫外到近红外均表现出很好的光学特性,可以作为高折射率材料很好地应用于光学薄膜中。     

原子层沉积制备Al_2O_3薄膜的光学性能研究

研究了原子层沉积制备氧化铝薄膜的光学性能。以三甲基铝(TMA)和水为前聚体,分别在基板温度为250℃和300℃的K9和石英玻璃衬底上沉积了Al2O3光学薄膜。采用分光光度计,X射线光电子能谱(XPS),X射线衍射(XRD),原子力显微镜(AFM),扫描电子显微镜(SEM)等分析手段对薄膜的微结构、表面形貌和光学特性进行了研究。结果表明,原子层沉积法制备的Al2O3薄膜在退火前后均呈现无定形结构,元素成分接近化学计量比,其表面粗糙度小于1.2nm,聚集密度高于0.97,光学非均匀性优于1%。同时在中紫外到近红外均有很好的光学性能,适合作为中间折射率和低折射率材料在光学薄膜中得到应用。     

光谱法确定离子束溅射Ta_2O_5/SiO_2薄膜的光学常数及其性能

采用双离子溅射的方法,在硅、石英基底上制备了单层Ta2O5、SiO2及双层Ta2O5/SiO2光学薄膜。结合Cauchy色散模型,利用石英基底上单层Ta2O5及双层Ta2O5/SiO2薄膜透射光谱曲线,采用改进的遗传单纯形混合算法,获得了Ta2O5和SiO2薄膜材料在400~700nm波段的光学常数。结果表明,理论分析值与实验测量值取得了很好的一致性,拟合出的单层Ta2O5薄膜折射率误差小于0.001,膜层厚度误差不超过1nm;双层Ta2O5/SiO2薄膜最大折射率误差小于0.004,最大厚度误差小于2.5nm。此外,还对400℃高温环境下双层Ta2O5/SiO2薄膜的微观结构、应力、表面形貌及光学性能变化进行了研究。     

Er2O3薄膜的光学常数和介电性能

采用射频磁控反应溅射技术,在不同的Ar/O2流量比条件下制备了系列Er2O3薄膜样品.采用椭偏光谱和紫外一可见光透射光谱测试分析技术,研究了Er2O3薄膜的折射率、消光系数、透射率和光学带隙等光学常数与制备工艺的关系.研究了不同条件下制备的Er2O3薄膜的介电常数和Ⅰ～Ⅴ特性.结果表明,Er2O3薄膜的折射率、禁带宽度和介电常数随Ar/O2流鼍比的增加而增加,而消光系数基本不随Ar:O2流量比的变化而变化.在Ar:O2流量比为7:1制备的Er2O3薄膜具有较好的物理性能,在可见红外波段其折射率约1.81,消光系数为3.7×10-6,禁带宽度5.73 eV,介电常数为10.5.     

不同沉积温度下非晶硅光学薄膜的光学特性研究

光学薄膜的光学特性是薄膜设计与制备的基础。硅材料是红外光学薄膜中一种重要的高折射率材料。研究了在不同沉积温度下非晶硅光学薄膜的折射率和消光系数的变化。结果表明,在200℃时,硅薄膜折射率最大,消光系数随温度升高而减小。     

紫外Sc_2O_3薄膜的光学和结构性能表征及其激光作用下的损伤机理

利用电子束蒸发方法,在不同沉积温度(50~350℃)下制备了Sc2O3薄膜。分别用分光光度计,小角掠入射X射线衍射仪和轮廓仪测试了薄膜样品的光谱、微结构和表面粗糙度信息,并用薄膜分析软件Essential Macleod计算了Sc2O3薄膜的折射率和消光系数。结果表明:随着沉积温度升高,Sc2O3薄膜结晶程度增强,晶粒尺寸增大,且较高的沉积温度有利于获得较高的折射率。最后用355 nm,8 ns的三倍频Nd:YAG激光器测试了其激光损伤阈值(LIDT),最大值为2.6 J/cm2,且阈值与薄膜的消光系数、表面粗糙度、光学损耗均呈现相反的变化趋势。用光学显微镜和扫描电子显微镜表征了该薄膜的破坏形貌,详细分析了薄膜在不同激光能量作用下破坏的发展过程,以及Sc2O3薄膜在355 nm紫外激光作用下LIDT与制备工艺的关系,重点分析了355 nm激光作用下薄膜的破坏机理。     

衬底温度对电子束沉积ZnSe薄膜性能影响研究

为了研究衬底温度对硒化锌薄膜微观结构和光学特性的影响,采用电子束蒸发技术在K9玻璃基底上制备了单层的硒化锌薄膜。通过研究薄膜的X射线衍射谱、透射光谱特性、表面形貌及粗糙度,分析了不同衬底温度下薄膜微观晶体结构和光学特性的变化规律。实验结果表明:在20～200℃的衬底温度范围内制备的ZnSe薄膜均为具有(111)晶面择优取向的纳米晶薄膜,随着衬底温度升高,基片上原子获得的动能增加,导致薄膜的晶粒尺寸变大、内应力和位错密度降低;同样在不同衬底温度下,薄膜的光学特性也不尽相同,随着衬底温度的升高,折射率和消光系数减小、光学带隙增加、薄膜的表面粗糙度降低。分析表明折射率下降是薄膜中空隙部分所占比例增加所致,而消光系数的下降是薄膜结晶度提高,内部缺陷减少造成的。     

Y2O3稳定ZrO2薄膜的结构和光学特性

用电子束蒸发法制备出四种不同Y2O3含量的Y2O3稳定ZrO2（YSZ）薄膜,用X射线衍射和透射光谱测定薄膜的结构和光学性能.结果表明：随着Y2O3含量的增加,ZrO2薄膜从单斜相向高温相（四方相和立方相）转变,获得了结构稳定的YSZ薄膜；YSZ薄膜的晶粒尺寸都比ZrO2薄膜的大,但随着Y2O3加入量的增加,晶粒尺寸有减小的趋势,薄膜表面也趋向光滑平整.所有YSZ薄膜的透射谱线都与ZrO2薄膜相似,在可见光和红外光区都有较高的透过率.Y2O3的加入还可以改变薄膜的折射率,在一定范围内可得到所需的任意折射率.     

比较2种溅射方法镀制的氧化硅薄膜

比较了磁控反应溅射(RMS)法与离子束反应溅射(RIBS)法沉积得到的氧化硅薄膜的光学特性,并确定了其对折射率n、消光系数k、沉积速率和混合工作气体Ar/O2中氧含量的依赖性关系。工作气体中O2含量大于15%时通过RMS法沉积的氧化硅薄膜在0.63μm波长折射率约为1.52~1.55,消光系数低于10-5。当O2含量在80%以上时RIBS方法沉积氧化硅薄膜的折射率n=1.52~1.6,消光系数低于10-5。用RMS沉积SiO2薄膜,当氧气量超过15%时发生反应模式,此时沉积速率下降近5倍。而用RIBS时,沉积速率并不依赖氧气在混合工作气体中的含量。     

溶胶-凝胶法制备SiO2基片Er3+∶Al2O3光学薄膜

用溶胶凝胶法在SiO2 基片上提拉制备了掺Er3 + ∶Al2 O3 光学薄膜。采用扫描电子显微镜、原子力显微镜、差热热重分析仪、X射线衍射仪研究了掺Er3 + ∶Al2 O3 光学薄膜的形貌和结构特性。在 90 0℃烧结后 ,SiO2 基片上提拉 15次形成厚度 8μm掺摩尔比 0 .0 1Er3 + 的面心立方结构γ Al2 O3 薄膜具有明显 (110 )择优取向 ,掺摩尔比 0 .0 1Er3 + 对γ Al2 O3 的晶体结构和结晶生长过程未产生显著影响。薄膜具有均匀多孔结构 ,平均粒径为 30～ 10 0nm ,平均孔径为 5 0～ 10 0nm ,表面起伏度为 10～ 2 0nm。掺摩尔比 0 .0 1Er3 + ∶γ Al2 O3 薄膜 ,获得了中心波长为1.5 34μm(半峰全宽为 36nm)的光致发光谱。     

Structure and optical properties of chemically synthesized titanium oxide deposited by evaporation technique

Titanium oxide inorganic ion exchange material was synthesized by hydrolysis with water and ammonia solution. Structural feature of the synthesized titanium oxide was analyzed using X-ray diffraction, X-ray fluorescence and infrared spectrometer technique. Tentative formula of titanium oxide was determined and written as TiO₂·0.58H₂O. Titanium oxide films were deposited on glass substrates by means of an electron beam evaporation technique at room temperature from bulk sample. The films were annealed at 250, 350, 450, and 550 °C temperatures. Transmittance, reflectance, optical energy gap, refractive index and extinction coefficient were investigated. The transmittance values of 85% in the visible region and 88% in the near infrared region have been obtained for titanium oxide film annealed at 550 °C. Kubelka-Munk function was used to evaluate the absorption coefficient which was used to determine the optical band gap. It was found that the optical band gap increases with increasing annealing temperature whereas the refractive index and extinction coefficient decreases.     

磁控溅射制备铬薄膜的结构和光电学性质(英文)

用直流磁控溅射技术在石英基片上制备不同厚度(5nm～114nm之间)的铬膜.使用X射线衍射仪和分光光度计分别检测薄膜的结构和光学性质,利用德鲁特模型和薄膜的透射、反射光谱计算铬膜的厚度和光学常量,并采用Van der Pauw方法测量薄膜电学性质.结果表明:制备的铬薄膜为体心立方的多晶态,随着膜厚的增加,薄膜的结晶性能提高,晶粒尺寸增大;在可见光区域,当膜厚小于32nm时,随着膜厚的增加,折射率快速减小,消光系数快速增大,当膜厚大于32nm时,折射率和消光系数均缓慢减小并逐渐趋于稳定;薄膜电阻率随膜厚的增加为一次指数衰减.     

磁控溅射制备铬薄膜的结构和光电学性质

用直流磁控溅射技术在石英基片上制备不同厚度(5 nm~114 nm之间)的铬膜.使用X射线衍射仪和分光光度计分别检测薄膜的结构和光学性质,利用德鲁特模型和薄膜的透射、反射光谱计算铬膜的厚度和光学常量,并采用Van der Pauw方法测量薄膜电学性质.结果表明:制备的铬薄膜为体心立方的多晶态,随着膜厚的增加,薄膜的结晶性能提高,晶粒尺寸增大;在可见光区域,当膜厚小于32 nm时,随着膜厚的增加,折射率快速减小,消光系数快速增大,当膜厚大于32 nm时,折射率和消光系数均缓慢减小并逐渐趋于稳定;薄膜电阻率随膜厚的增加为一次指数衰减.     

Electrical conductivity and optical properties of ZnO nanostructured thin film

The electrical conductivity, structural and optical properties of ZnO nanostructured semiconductor thin film prepared by sol-gel spin coating method have been investigated. The X-ray diffraction result indicates that the ZnO film has the polycrystalline nature with average grain size of 28 nm. The optical transmittance spectrum indicates the average transmittance higher than 90% in visible region. The optical band gap, Urbach energy and optical constants (refractive index, extinction coefficient, real and imaginary parts of the dielectric constant) of the film were determined. The electrical conductivity of the film dependence of temperature was measured to identify the dominant conductivity mechanism. The conductivity mechanism of the film is the thermally activated band conduction. The electrical conductivity and optical results revealed that the ZnO film is an n-type nanostructured semiconductor with a direct band gap of about 3.30 eV at room temperature.     

Synthesis and optical characterization of nanocrystalline CdTe thin films

From several years the study of binary compounds has been intensified in order to find new materials for solar photocells. The development of thin film solar cells is an active area of research at this time. Much attention has been paid to the development of low cost, high efficiency thin film solar cells. CdTe is one of the suitable candidates for the production of thin film solar cells due to its ideal band gap, high absorption coefficient. The present work deals with thickness dependent study of CdTe thin films. Nanocrystalline CdTe bulk powder was synthesized by wet chemical route at pH≈11.2 using cadmium chloride and potassium telluride as starting materials. The product sample was characterized by transmission electron microscope, X-ray diffraction and scanning electron microscope. The structural characteristics studied by X-ray diffraction showed that the films are polycrystalline in nature. CdTe thin films with thickness 40, 60, 80 and 100 nm were prepared on glass substrates by using thermal evaporation onto glass substrate under a vacuum of 10⁻⁶ Torr. The optical constants (absorption coefficient, optical band gap, refractive index, extinction coefficient, real and imaginary part of dielectric constant) of CdTe thin films was studied as a function of photon energy in the wavelength region 400–2000 nm. Analysis of the optical absorption data shows that the rule of direct transitions predominates. It has been found that the absorption coefficient, refractive index (n) and extinction coefficient (k) decreases while the values of optical band gap increase with an increase in thickness from 40 to 100 nm, which can be explained qualitatively by a thickness dependence of the grain size through decrease in grain boundary barrier height with grain size.     

SiO2和HfO2薄膜光学性能的椭偏光谱测量

结合XRD和原子力显微镜等方法,利用椭圆偏振光谱仪测试了单层SiO2薄膜（K9基片）和单层HfO2薄膜（K9基片）的椭偏参数,并用Sellmeier模型和Cauchy模型对两种薄膜进行拟合,获得了SiO2薄膜和HfO2薄膜在300-800nm波段内的色散关系。用X射线衍射仪确定薄膜结构,并用原子力显微镜观察薄膜的微观形貌,分析表明：SiO2薄膜晶相结构呈现无定型结构,HfO2薄膜的晶相结构呈现单斜相结构;薄膜光学常数的大小和薄膜的表面形貌有关;Sellmeier和Cauchy模型较好地描述了该波段内薄膜的光学性能,并得到薄膜的折射率和消光系数等光学常数随波长的变化规律。     

Derivation of the optical constants of spin coated CeO2-TiO2-ZrO2 thin films prepared by sol-gel route

Ternary thin films of cerium titanium zirconium mixed oxide were prepared by the sol-gel process and deposited by a spin coating technique at different spin speeds (1000-4000 rpm). Ceric ammonium nitrate, Ce(NO₃)₆(NH₄)₂, titanium butoxide, Ti[O(CH₂)₃CH₃]₄, and zirconium propoxide, Zr(OCH₂CH₂CH₃)₄, were used as starting materials. Differential calorimetric analysis (DSC) and thermogravimetric analysis (TGA) were carried out on the CeO₂-TiO₂-ZrO₂ gel to study the decomposition and phase transition of the gel. For molecular, structural, elemental, and morphological characterization of the films, Fourier Transform Infrared (FTIR) spectral analysis, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), cross-sectional scanning electron microscopy (SEM), and atomic force microscopy (AFM) were carried out. All the ternary oxide thin films were amorphous. The optical constants (refractive index, extinction coefficient, band gap) and thickness of the films were determined in the 350-1000 nm wavelength range by using an nkd spectrophotometer. The refractive index, extinction coefficient, and thickness of the films were changed by varying the spin speed. The oscillator and dispersion energies were obtained using the Wemple-DiDomenico dispersion relationship. The optical band gap is independent of the spin speed and has a value of about E_g≈2.82±0.04 eV for indirect transition.     

Structural characterization and optical properties of UO2 thin films by magnetron sputtering

Uranium dioxide films were deposited on Si (1 1 1) substrates by dc magnetron sputtering method at different sputtering parameters. The structure, morphology and chemical state of the films were studied by field emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy. Influences of film thickness on the microstructure and optical properties were investigated. Experimental results show that the film crystallites are preferentially oriented with the (1 1 1) planes. The average grain size increases with increasing film thickness. AFM images show that the root mean square roughness of the films is between 1.2 nm and 2.1 nm. Optical constants (refractive index, extinction coefficient) of the films in the wavelength range of 350-1000 nm are obtained by ellipsometric spectroscopy. The result shows that the refractive index decreases with the increasing film thickness, while extinction coefficient increases with the film thickness.     

Optical inhomogeneity of ZnS films deposited by thermal evaporation

Zinc sulfide (ZnS) films with optical thickness (reference wavelength is 620 nm) ranging from 310 to 1240 nm were deposited on quartz substrates at room temperature by a thermal evaporation system. The structure and morphology of the films were investigated by X-ray diffraction, atomic force microscopy, respectively. The optical properties of the films were determined by in situ transmittance measurements and wideband spectra photometric measurements, respectively. The experimental results show that the films exhibit cubic structure, and the intensity of the (2 2 0) diffraction peak enhances with the increase of optical thickness. Surface grain size and surface roughness increase monotonously with increasing film thickness. Refractive indices and extinction coefficients calculated by in situ transmittance measurements are well consistent with those calculated by wideband spectra photometric measurements. Both the refractive index and packing density of the film increase as the increase of film thickness, which confirms the film is positive inhomogeneous and has an expanding columnar structure. Extinction coefficients of the films increase with increasing film thickness, which results from the increase of surface roughness.     

Preparation and optical constants of the nano-crystal and polymer composite Bi4Ti3O12/PMMA thin films

Bismuth titanate, Bi₄Ti₃O₁₂ (BTO), is a typical ferroelectric material with useful properties for optical memory, piezoelectric and electro-optic devices. Its nano-crystals were compounded by the chemical solution decomposition technique. Its structure and size were analyzed by X-ray diffraction and transmissive electron microscopy. The composite thin film of BTO nano-crystals and high transparency polymethylmethacrylate (PMMA) polymer was prepared by spin coating. The transmitted spectrum of BTO/PMMA composite thin film in 300–1500 nm was measured. The film thickness d and the optical constants of the film, such as the refractive index n, the absorption coefficient α, and the extinction coefficient κ were obtained using the data from the transmitted spectrum.