溶胶-凝胶法制备高折射率TiO2薄膜

采用溶胶- 凝胶法制备了TiO2纳米晶溶胶,并以旋涂法（spin-coating）镀制了高折射率光学薄膜。借助光散射技术和透射电镜研究了溶胶的微结构。采用原子力显微镜、场发射扫描电镜、紫外-可见-近红外光谱仪、椭偏仪、漫反射吸收光谱及强激光辐照实验,对膜层的结构、光学性能及抗激光损伤性能进行了系统的表征。结果显示:纳米晶薄膜的折射率达到了1.9,而传统的溶胶-凝胶薄膜折射率只有1.6;同时纳米晶薄膜的抗激光损伤阈值与传统的溶胶-凝胶薄膜相差不大,在1 064 nm处分别为16.3 J/cm2(3 ns脉冲) 和16.6 J/cm2(3 ns脉冲);纳米晶溶胶薄膜可以在保持较高抗激光损伤阈值情况下,大幅度提高薄膜折射率。     

溶胶-凝胶法制备高折射率TiO2薄膜

 采用溶胶- 凝胶法制备了TiO₂纳米晶溶胶,并以旋涂法（spin-coating）镀制了高折射率光学薄膜。借助光散射技术和透射电镜研究了溶胶的微结构。采用原子力显微镜、场发射扫描电镜、紫外-可见-近红外光谱仪、椭偏仪、漫反射吸收光谱及强激光辐照实验,对膜层的结构、光学性能及抗激光损伤性能进行了系统的表征。结果显示:纳米晶薄膜的折射率达到了1.9,而传统的溶胶-凝胶薄膜折射率只有1.6;同时纳米晶薄膜的抗激光损伤阈值与传统的溶胶-凝胶薄膜相差不大,在1 064 nm处分别为16.3 J/cm²(3 ns脉冲) 和16.6 J/cm²(3 ns脉冲);纳米晶溶胶薄膜可以在保持较高抗激光损伤阈值情况下,大幅度提高薄膜折射率。     

ZnO·TiO2双层复合薄膜的制备及其光学性能的研究

采用溶胶-凝胶法(Sol-Gel),分别以乙酸锌(Zn(CH₃COO)₂H₂O)、钛酸酊酯(Ti(OC₄H₉)₄)为锌源和钛源,在玻璃衬底以及硅衬底上制备了不同浓度的、均匀的、结晶质量良好的单层ZnO、TiO₂薄膜及双层的ZnO·TiO₂复合薄膜。结果表明,所制备的单层本征ZnO、TiO₂薄膜分别沿(002)、(101)晶面生长,且当本征ZnO、TiO₂的浓度分别为0.45 mol/L、0.65 mol/L时,择优取向生长最明显。ZnO·TiO₂复合薄膜的(101)、(004)特征峰明显,且0.45 mol/L/0.55 mol/L的双层ZnO·TiO₂复合薄膜结晶质量最好;薄膜表面最为平整,粒子分布均匀,粘连现象最少;对紫外光的吸收最强,禁带宽度为3.39 eV。     

溶胶-凝胶VO2薄膜转换特性研究

利用溶胶凝胶法在SiO2Si衬底上沉积高取向的V2O5薄膜,在压强低于2Pa,温度高于400℃的条件下,对V2O5薄膜进行真空烘烤,获得了电阻率变化3个数量级以上、弛豫宽度为62℃的VO2多晶薄膜.以X射线衍射(XRD)、扫描电子显微镜(SEM)图和电阻率转换特性等实验结果为依据,详细分析了溶胶凝胶薄膜在真空烘烤时从V2O5向VO2的转化,它经历了从VnO2n+1(n=2,3,4,6)到VO2的过程.实验证明,根据选择合适的成膜热处理条件和真空烘烤条件是实现溶胶凝胶V2O5结构向VO2结构成功转换的关键 关键词： 溶胶-凝胶法 氧化钒薄膜 VO2膜转换特性     

基于透射光谱确定溶胶凝胶ZrO2薄膜的光学常数

基于溶胶凝胶ZrO₂薄膜的紫外/可见/近红外透射实验光谱,采用Swanepoel方法结合Wemple-DiDomenico色散模型,方便地导出了ZrO₂薄膜在200—1200nm波长范围内的光学常数,包括折射率、色散常数、膜层厚度、吸收系数及能量带隙.研究发现,溶胶凝胶ZrO₂薄膜具有高折射率(1.63—1.93,测试波长为632.8nm)、低吸收和直接能量带隙(4.97—5.63eV) 等光学特性,而且其光学常数对薄膜制备过程中的重要工艺 关键词： 光学常数 Swanepoel方法 2薄膜')" href="#">ZrO₂薄膜 热处理     

利用透射光谱与X射线反射谱精确测量溶胶-凝胶TiO2薄膜厚度和光学常数

在洁净K9玻璃基底上沉积TiO2薄膜,将透射光谱和X射线反射光谱相结合分析获得膜层的厚度和光学常数。X射线反射谱拟合能精确得到膜层的厚度、电子密度及表面和界面粗糙度,其中膜层厚度的数值为透射光谱的分析提供了重要参考。基于Forouhi-Bloomer色散模型拟合膜层透射光谱,得到薄膜折射率和消光系数,理论曲线和实验曲线吻合良好。对于同一样品,两种光谱拟合分析得到的厚度数值非常接近,差值最大为4.9nm,说明两种方法的结合能够提高光学分析结果的可靠性。     

溶胶-凝胶法Er2O3薄膜的结构和光学特性

针对稀土Er掺杂Si光源中Er离子掺杂浓度低的问题,采用溶胶-凝胶（Sol-gel）法在Si(100)和SiO2/Si(100)基片上旋涂法制备Er₂O₃光学薄膜,Er离子浓度与以前掺杂方法相比提高了2个数量级.900 ℃热处理获得单一立方结构的Er₂O₃薄膜材料.光致发光（PL）特性研究表明在654 nm波长的激光泵浦下,Er₂O₃薄膜材料获得了1.535 μm的发光峰,并具有较小的温度猝灭1/5.在SiO₂/Si(100)基体上制备的Er2O3薄膜材料的光致发光强度比Si(100)基体上制备的薄膜提高2-3倍.研究结果表明具有强光致发光特性的Er₂O₃薄膜是一种有前景的硅基光源和放大器材料.     

氨处理溶胶-凝胶SnO2薄膜的光学性质

采用溶胶－凝胶法制备ＳｎＯ２薄膜,通过对薄膜的不同处理方式（热处理和氨处理）所获得的ＳｎＯ２薄膜的比较,研究了氨处理ＳｎＯ２薄膜的光学性质。实验结果表明氨处理溶胶－凝胶ＳｎＯ２薄膜不仅具有良好的增透特性,同时也具有较好的机械强度和电学性能。     

溶胶-凝胶法制备纳米多孔SiO2薄膜

以正硅酸乙酯(TEOS)为原料，采用旋转涂敷的方法，结合溶胶-凝胶技术在硅衬底上制备超低介电常数多孔SiO₂薄膜.采用两种不同的改性方法对薄膜表面进行改性，傅里 叶变换红外光谱分析发现改性后薄膜中含有大量的—CH₃键，从而减少了孔洞塌陷.用扫 描电子显微镜观察薄膜的表面形貌，发现薄膜内孔洞尺寸在70—80 nm之间.调节溶胶pH值，发现pH值越小凝胶时间越长.对改性样品热处理的结果表明，在300 ℃时介电常数最低达2.05. 关键词： 2')" href="#">多孔SiO₂ 低介电常数 溶胶-凝胶     

溶胶-凝胶ZrO2-TiO2高折射率光学膜层的抗激光损伤性能研究

采用溶胶-凝胶方法制备了ZrO₂-TiO₂(Ti含量为0—100mol%)高折射率光学薄膜. 借助激光动态光散射技术研究溶胶微结构. 采用傅里叶变换红外光谱、原子力显微镜、薄膜光学常数分析仪、漫反射吸收光谱及强激光辐照实验，对膜层的结构、光学性能及抗激光损伤性能进行了系统表征. 结果显示，溶胶-凝胶工艺可以在部分牺牲折射率的情况下，使膜层的抗激光损伤性能得到大幅度提升. 随Ti含量从0mol%增加至100mol%，膜层的平均损伤阈值呈下降趋势，当Ti含量从0mol%增加至60mol%时，平均损伤阈值从57.1J/cm²下降到21.1J/cm²(辐照激光波长为1053nm，脉冲宽度为10ns，“R/1”测试模式)，当Ti含量从60mol%增加至100mol%时，平均损伤阈值变化很小. 综合溶胶微结构、膜层光学性能和损伤实验结果可以推断，强激光诱导多光子吸收是引起膜层损伤的主要原因. 不同配比的复合膜之间光学带隙的显著差异导致相同辐照激光情况下多光子吸收的概率发生变化，从而导致损伤阈值的规律性变化. 关键词： 2-TiO₂薄膜')" href="#">ZrO₂-TiO₂薄膜 溶胶-凝胶 激光诱导损伤 光学带隙     

Thermally tunable optical constants of vanadium dioxide thin films measured by spectroscopic ellipsometry

Smart materials with reversible tunable optical constants from visible to near-infrared wavelengths could enable excellent control over the resonant response in metamaterials, tunable plasmonic nanostructures, optical memory based on phase transition and thermally tunable optical devices. Vanadium dioxide (VO₂) is a promising candidate that exhibits a dramatic change in its complex refraction index or complex dielectric function arising from a structural phase transition from semiconductor to metal at a critical temperature of 70 °C. We demonstrated the thermal controllable reversible tunability of optical constants of VO₂ thin films. The optical/dielectric constants showed an abrupt thermal hysteresis which confirms clearly the electronic structural changes. Temperature dependence of dielectric constants as well as optical conductivity of sputtered VO₂ thin films was also reported and compared to previous theoretical and experimental reports.     

椭偏与光度法联用精确测定吸收薄膜的光学常数与厚度

介绍了一种同时利用椭偏仪和分光光度计精确测量薄膜光学常数的方法, 并详细比较了该方法与使用单一椭偏仪拟合结果的可靠性.采用可变入射角光谱型椭偏仪（VASE）表征了250—1700 nm波段辉光放电法沉积的类金刚石薄膜,研究发现当仅用椭偏参数拟合时,由于厚度与折射率、消光系数的强烈相关性,无法得到吸收薄膜光学常数的准确解.如果加入分光光度计测得的透射率同时拟合,得到的结果具有很好的惟一性.该方法无需设定色散模型即可快速拟合出理想的结果,特别适合于确定透明衬底上较薄吸收膜的光学常数. 关键词： 光学常数 光谱型椭偏仪 吸收薄膜 透射率     

椭偏与光度法联用精确测定吸收薄膜的光学常数与厚度

介绍了一种同时利用椭偏仪和分光光度计精确测量薄膜光学常数的方法, 并详细比较了该方法与使用单一椭偏仪拟合结果的可靠性.采用可变入射角光谱型椭偏仪（VASE）表征了250—1700 nm波段辉光放电法沉积的类金刚石薄膜,研究发现当仅用椭偏参数拟合时,由于厚度与折射率、消光系数的强烈相关性,无法得到吸收薄膜光学常数的准确解.如果加入分光光度计测得的透射率同时拟合,得到的结果具有很好的惟一性.该方法无需设定色散模型即可快速拟合出理想的结果,特别适合于确定透明衬底上较薄吸收膜的光学常数.     

Synthesis and photocatalytic properties of porous TiO2 films prepared by ODA/sol-gel method

Porous TiO₂ films were deposited on SiO₂ pre-coated glass-slides by sol-gel method using octadecylamine (ODA) as template. The amount of ODA in the sol played an important role on the physicochemical properties and photocatalytic performance of the TiO₂ films. The films prepared at different conditions were all composed of anatase titanium dioxide crystals, and TiO₂ crystalline size got larger with increasing ODA amount. The maximum specific surface area of 41.5 m²/g was obtained for TiO₂ powders prepared from titanium sol containing 2.0 g ODA. Methyl orange degradation rate was enhanced along with increasing ODA amount and reached the maximal value at 2.0 g addition of ODA. After 40 min of UV-light irradiation, methyl orange degradation rate reached 30.5% on the porous film, which was about 10% higher than that on the smooth film. Porous TiO₂ film showed almost constant activity with slight decrease from 30.5% to 28.5% after 4 times of recycles.     

Morphology and natural wettability properties of sol-gel derived TiO2-SiO2 composite thin films

Previous studies suggest that granular interfaces induce a natural and persistent super-hydrophilicity in TiO₂-SiO₂ composite thin films deposited by sol-gel route. This effect enables to consider self-cleaning applications that do not require a permanent UV exposure, whereas such a permanent exposure is necessary for pure TiO₂ films. In this study, TiO₂-SiO₂ composite thin films have been deposited from a TiO₂ anatase crystalline suspension and different SiO₂ polymeric sols. Wettability studies show that a suitable control of the TiO₂-SiO₂ mixed sol formulations noticeably enhances persistence of the natural super-hydrophilicity in composite films. It is shown that, beside granular interface effects, modifications in the composite film morphologies can noticeably influence wettability properties.     

Influence of annealing process on conductive properties of Nb-doped TiO2 polycrystalline films prepared by sol-gel method

Nb-doped TiO₂ (TNO) thin films were prepared by sol-gel dip-coating method with Nb content in a wide range of 0-20 at.%. The prepared films were preheated at 400 °C and then undertaken by two different post-annealing processes: (a) three times vacuum annealing and (b) multi-round annealing. The designed multi-round annealing was shown to be an effective way to improve the conductive properties of the films, compared to the traditional vacuum annealing process. The minimum resistivity reached approximately 0.5 Ω cm with Nb doping concentration around 12 at.%, and the carrier density increased with Nb-doping concentration until the critical point of 12 at.%, which might be the optimal doping content for our TNO films prepared by sol-gel method.     

射频磁控反应溅射制备的Ag2O薄膜的椭圆偏振光谱研究

Ag₂O薄膜在新型超高存储密度光盘和磁光盘方面具有潜在的应用前景.利用射频磁控反应溅射技术, 通过调节衬底温度在沉积气压为0.2 Pa、氧氩比为2:3的条件下制备了一系列Ag₂O 薄膜.利用通用振子模型(包括1个Tauc-Lorentz振子和2个Lorentz 振子)拟合了薄膜的椭圆偏振光谱.在1.5-3.5 eV能量区间,薄膜的折射率在2.2-2.7之间, 消光系数在0.3-0.9之间. 在3.5-4.5 eV能量区间,薄膜呈现了明显的反常色散,揭示Ag₂O薄膜的等离子体振荡频率在 3.5-4.5 eV之间. 随着衬底温度的升高,薄膜的光学吸收边总体上发生了红移, 该红移归结于薄膜晶格微观应变随衬底温度的升高而增大. Ag₂O薄膜的光学常数表现出典型的介质材料特性.     

Extraction of optical constants and thickness of nanometre scale TiO2 film

TiOTiO2 薄膜 沉积物 磁电管喷射系统 X射线 发射光谱TiO₂ thin films, pointwise constrained optimization approach, constrained nonlinear programming, optical constants, parameters extractionProject supported by Shanghai Municipal Commission for Science and Technology (Grant No 03DZ14025) and National Basic Research Program of China (Grant No 2006CB300406).3/4/2005 12:00:00 AM2005-03-042005-07-28TiO2 thin films were deposited on glass substrates by sputtering in a conventional rf magnetron sputtering system. X-ray diffraction pattern and transmission spectrum were measured. The curves of refraction index and extinction coefficient distributions as well as the thickness of films calculated from transmission spectrum were obtained. The optimization problem was also solved using a method based on a constrained nonlinear programming algorithm.