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介质薄膜的透射光谱测量及其光学参数的分析 总被引:7,自引:1,他引:6
介绍介质薄膜透射光谱的测量以及基于分析薄膜透射光谱的计算薄膜光学参数的方法。对制备在玻璃基板上的二氧化钛,二氧化硅和氧化锌薄膜进行了可见光谱区的透射比测量,并用包络线方法和最优化方法对这些透明薄膜的光学参数进行了计算和分析。 相似文献
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磁控溅射SiC薄膜及其光电特性研究 总被引:1,自引:0,他引:1
用射频磁控溅射法制备了SiC薄膜,并对其进行了退火处理.用AFM观察了薄膜的表面形貌,测量了薄膜的厚度与透射光谱.用J.C.Manifacier提出并由R.Swanepoel加以修正和完善的包络线法对薄膜透射光谱进行了分析计算,并结合Tuac公式确定了薄膜的光学带隙.结果表明:在不同射频功率下制备的薄膜均有较强的蓝紫光吸收特性,在低功率下可制备出表面平整,吸收系数小,光学带隙大的薄膜;退火处理后薄膜的吸收系数减小,光学带隙增大,晶粒向圆形转化且尺寸变大. 相似文献
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本文采用射频磁控反应溅射法于常温下在硅片和玻璃基片上制备ZnO和掺铝ZnO薄膜,将铝丝置于ZnO靶材上共同溅射来达到掺杂的效果,利用不同长度的铝丝以获得不同的掺杂量。通过X射线衍射法对薄膜进行结构分析,利用紫外-可见分光光度计获得薄膜的透过率光谱,霍尔效应仪测量薄膜的电学性能。发现所制备的样品在可见光区域透过率达到80%以上,达到了透明膜的要求;掺Al后的ZnO膜电阻率最低达到了4.25×10-4Ω·cm;结构表征发现样品的(002)晶面有明显衍射峰。基于包络线方法通过透射谱拟合计算了薄膜样品的折射率和厚度。 相似文献
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10.4—12.5μm单层红外增透膜的研究 总被引:1,自引:0,他引:1
红外光学薄膜的种类不但少,而且机械强度较差,尤其在中红外波段更是如此。根据薄膜光学理论计算了ZnS/Ge/ZnS、CdTe/Ge/CdTe和ZnSe/Ge/ZnSe三种ARC组合的反射率和透射率。详细分析研究了吸收和色散对ZnS/Ge/ZnS极值透射率和反射率以及极值波长的影响。计算结果表明,ZnS/Ge/ZnS组合的光谱特性最好,吸收和色散对薄膜的光谱特性有一定影响。相对而言ZnS薄膜的机械强度较好。在理论计算的基础上,利用离子束辅助沉积方法制备ZnS薄膜,检测分析了薄膜的光谱性能,考察了薄膜的耐久性。 相似文献
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用激光脉冲沉积(PLD)法在MgO(001)衬底上成功地生长、制备出了外延铌酸锶钡钠(SCNN)电光薄膜.对生长制备出的SCNN电光薄膜用X射线衍射对其微观结构进行了测量研究;X射线衍射结果显示生长在MgO(001)衬底上的SCNN电光薄膜是外延膜;对生长在MgO(001)衬底上的外延SCNN电光薄膜在200~900nm光谱范围的透射光谱进行了测量研究,通过对薄膜透射光谱的振荡曲线分析计算得到了SCNN电光薄膜的光学常数,结果发现外延SCNN电光薄膜的折射率符合单电子模型. 相似文献
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针对射频反应性溅射 Cd- In合金靶沉积的透明导电 CdIn2O4薄膜可见光区和近红外透射区透射和反射谱,分别采用包络线法迭代计算和 Szczyrbowski提出的非均匀膜模型计算出了薄膜的光学常数。根据 Drude理论求出了自由载流子有效质量,并与通过等离子体波长λ p所确定的有效质量进行了比较。 相似文献
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Optical characterization of dielectric and semiconductor thin films by use of transmission data 总被引:3,自引:0,他引:3
Cisneros JI 《Applied optics》1998,37(22):5262-5270
A method to calculate the optical functions n(lambda) and k(lambda) by use of the transmission spectrum of a dielectric or semiconducting thin film measured at normal incidence is described. The spectrum should include the low-absorption region and the absorption edge to yield the relevant optical characteristics of the material. The formulas are derived from electromagnetic theory with no simplifying assumptions. Transparent films are considered as a particular case for which a simple method of calculation is proposed. In the general case of absorbing films the method takes advantage of some properties of the transmittance T(lambda) to permit the parameters in the two regions mentioned above to be calculated separately. The interference fringes and the optical path at the extrema of T(lambda) are exploited for determining with precision the refractive index and the film thickness. The absorption coefficient is computed at the absorption edge by an efficient iterative method. At the transition zone between the interference region and the absorption edge artifacts in the absorption curve are avoided. A small amount of absorption of the substrate is allowed for in the theory by means of a factor determined from an independent measurement, thus improving the quality of the results. Application of the method to a transmission spectrum of an a:Si(x)N(1-x):H film is illustrated in detail. Refractive index, dispersion parameters, film thickness, absorption coefficient, and optical gap are given with the help of tables and graphs. 相似文献
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Anis Akkari Cathy Guasch Michel Castagne Najoua Kamoun-Turki 《Journal of Materials Science》2011,46(19):6285-6292
Multilayers of zinc blend SnS crystalline thin film have been deposited onto glass substrates by a chemical bath deposition (CBD) method. The envelope method, based on the optical transmission spectrum taken at normal incidence, has been successfully applied to determine the layer thickness and to characterize optical properties of thin films having low surface roughness. Optical constants such as refractive index n, extinction coefficient k, as well as the real (??r) and imaginary (??i) parts of the dielectric constant were determined from transmittance spectrum using this method. Obtained low value of the extinction coefficient in the transparency domain is a good indication of film surface smoothness and homogeneity. To perform the heterojunction structure based on SnS absorber material, cubic In2S3:Al was deposited on SnO2:F/glass as window layer using CBD with different aluminum content. Optical properties of these films were evaluated. 相似文献
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E. R. Shaaban Mohamed N. Abd-el Salam M. Mohamed M. A. Abdel-Rahim A. Y. Abdel-Latief 《Journal of Materials Science: Materials in Electronics》2017,28(18):13379-13390
Thin films of (As50Se50)100?xAgx (with 0?≤?x?≤?25 s) metal-chalcogenide glasses were deposited onto glass substrates by thermal evaporation technique under high vacuum (10?6 mbar). The optical constants as well as the average thickness of the studied films are determined by the Swanepoel envelope method which is based on the optical transmission spectra measured in the spectral range 300–2500 nm. This method enables the transformation of the optical-transmission spectrum of a thin film of wedge-shaped thickness into the spectrum of a uniform film, whose thickness is equal to the average thickness of the non-uniform layer. The dispersion of the refractive index is discussed in terms of the Wemple–DiDomenico single-oscillator model. The optical absorption edge is described using the non-direct transition model proposed by Tauc relation. Analysis of the optical data revealed that an addition of Ag in the range from 0 to 25 at.% to the (As50Se50)100?x binary alloys affected the optical parameters of the investigated thin films. For instance, the optical band gap decreased from 1.661 to 1.441 eV with increasing the Ag content from 0 to 25 at.%. The results were discussed in terms of Mott and Davis model as well as chemical-bond approach. 相似文献
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Lanthanum modified lead zirconate titanate (PLZT) thin films were fabricated on sapphire (0001) substrate by sol-gel method. The cell parameters of films were calculated with help of whole-pattern fitting procedure. The evolution of strain, shift of absorption edge and change in the band tailing with film thickness were found and analyzed for amorphous and polycrystalline PLZT films. The refractive index n was computed with help of “Envelope method” and dielectric function was calculated by fitting the measured optical transmission spectrum. 相似文献
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The role played by a glass substrate on the accurate determination of the optical constants and the thickness of a thin dielectric film deposited on it, when well-known envelope methods are used, is discussed. Analytical expressions for the two envelopes of the optical transmission spectra corresponding to film. with both uniform and nonuniform thicknesses are derived, assuming the substrate to be a weakly absorbing layer. It is shown that accurate determination of the refractive index and the film thickness is notably improved when the absorption of the substrate is considered. The analytical expressions for the upper and lower envelope, are used to characterize optically and geometrically both uniform and nonuniform amorphous chalcogenide films. The results obtained are compared with those derived by use of expressions for the envelopes that neglect the substrate absorption. The comparison shows that overestimated refractive indexes and underestimated thicknesses are obtained when the conventional approach, in which the substrate absorption is neglected, is used. 相似文献
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The optical behavior of a thin film, that is, peak positions and intensities, is discussed for transmission under a thin-film approximation. The infrared transmission spectra of thin films, both standing films and those on dielectric substrates, are simulated for s and p polarization at various angles of incidence. For spectral simulation, the matrix method is used in conjunction with noise-free complex refractive indices based on the dispersion theory. The peak positions in the simulated spectra are compared with transverse optic and longitudinal optic frequencies based on the macroscopic theory. The simulated peak intensities for the standing films are compared with the prediction based on the thin-film approximation. Furthermore, it is found from the spectral simulation for thin films on dielectric substrates that the peak intensity for a thin film may depend on the thickness and refractive index of the substrate. 相似文献
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Transmission spectra of bilayers of a strongly absorbing dye molecule on thin semitransparent metallic films show a pronounced variation of the shape as a function of the thickness of the metal film. The shape changes with increasing thickness of the metal film from the form of an absorption spectrum as determined by the imaginary part of the dielectric function to an antisymmetric shape characteristic of the dispersion of the real part of the dielectric function in the vicinity of a resonance. These different spectra shapes were exploited to derive the complex dielectric function of a dye layer from transmission spectra of the layer on metal films of a different thickness. This method proved to be a simple alternative to determination of the dielectric function of a thin film of a dye by spectroscopic ellipsometry. 相似文献
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A new calculating method to deduce optical constants n, k and thickness d from the fringe pattern of the transmission spectrum is proposed. In this method the optical parameters are determined using only one curve of the transmission spectra even for thin films where nd < /4. The method is demonstrated by experimental data obtained using evaporated vacuum deposited TiO2 thin film on a glass substrate. The experimental values are in very good agreement with those calculated using the above described technique. 相似文献
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C. Vijayan M. Pandiaraman N. Soundararajan R. Chandramohan V. Dhanasekaran K. Sundaram T. Mahalingam A. John Peter 《Journal of Materials Science: Materials in Electronics》2011,22(5):545-550
Semiconducting Ag2SeTe thin films were prepared with different thicknesses onto glass substrates at room temperature using thermal evaporation technique. The structural properties were determined as a function of thickness by XRD exhibiting no preferential orientation along any plane, however the films are found to have peaks corresponding to mixed phase. The XRD studies were used to calculate the crystallite size and microstrain of the Ag2SeTe films. The calculated microstructure parameters reveal that the crystallite size increases and micro strain decreases with increasing film thickness. The refractive index, dielectric constants and thereby the optical bandgap of the films were calculated from transmittance spectral data recorded in the range 400?C1200 nm by UV?CVIS-Spectrometer. The direct optical bandgap of the Ag2SeTe thin films deposited on glass substrates with different thicknesses 50?C230 nm were found to be in the range 1.48?C1.59 eV. The carrier density value is estimated to be around 9.8 × 1021 cm?1 for the film thickness of 150 nm. The compositions estimated from the optical band gap studies reveal a value of 0.75 for Tellurium concentration. These structural and optical parameters are found to be very sensitive to the thin film thickness. 相似文献
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Surface plasmon resonance enhanced transmission through metal-coated nanostructures represents a highly sensitive yet simple method for quantitative measurement of surface processes and is particularly useful in the development of thin film and adsorption sensors. Diffraction-induced surface plasmon excitation can produce enhanced transmission at select regions of the visible spectrum, and wavelength shifts associated with these transmission peaks can be used to track adsorption processes and film formation. In this report, we describe a simple optical microscope-based method for monitoring the first-order diffracted peaks associated with enhanced transmission through a gold-coated diffraction grating. A Bertrand lens is used to focus the grating's diffraction image onto a CCD camera, and the spatial position of the diffracted peaks can be readily transformed into a spectral signature of the transmitted light without the use of a spectrometer. The surface plasmon peaks appear as a region of enhanced transmission when the sample is illuminated with p-polarized light, and the peak position reflects the local dielectric properties of the metal interface, including the presence of thin films. The ability to track the position of the plasmon peak and, thus, measure film thickness is demonstrated using the diffracted peaks for samples possessing thin films of silicon oxide. The experimental results are then compared with calculations of optical diffraction through a model, film-coated grating using the rigorously coupled wave analysis simulation method. 相似文献