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1.
根据多孔阳极氧化铝(AAO)薄膜的实验透射谱(200—2500nm),采用极值包络线算法确定其光学常数,并由此较精确地计算出AAO薄膜样品在该波段的光学常数.结果表明,多孔氧化铝薄膜表现出直接带隙(能隙约4.5eV)半导体的光学特性,且其光学常数与制样中的重要工艺参数阳极氧化电压有显著的相关性,即随阳极氧化电压的增加,AAO薄膜的厚度、折射率和光学能隙变大,消光系数减小.同时,计算得到的薄膜厚度与实测值相吻合,则说明计算结果和实验值是自洽的.
关键词:
薄膜光学
光学常数
多孔阳极氧化铝
阳极氧化电压 相似文献
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The element and phase composition of periodic nanosize columnar structures of anodic tantalum oxide is investigated by the
methods of electron microscopy and IR spectroscopy. The effect of voltage in forming a two-layer Ta-Al composite on the composition
and structure of columnar anodic tantalum oxides is determined.
Deceased. 相似文献
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Periodic column structures of anodic tantalum oxide (ATO), formed by anodizing in different regimes a Ta—Al two-layer thin-film
composition in an oxalic-acid solution as well as the films of dense anodic oxide and thermal tantalum oxide, are investigated
by the methods of scanning electron microscopy and reflection IR spectroscopy. It is established that the ATO nano-size columns
are composed of at least three known oxide phases from a Ta—O system: TaO, TaO2 and Ta2O5. The structure of tantalum oxide compounds is amorphous with the near order (inclusions) of TaO2 rutile, rhombic Ta2O5, and α- and β-modifications of tantalum pentoxide. The dense-ATO films are distinguished by a more disordered structure of
the oxygen compounds of tantalum and an increased content of amorphous tantalum pentoxide. The thermal-ATO films have the
most ordered structure of all the oxide phases that enter in their composition and increased relative contents of α- and β-Ta2O3.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 6, pp. 850–856, November–December, 1998. 相似文献
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V. I. Kukuev E. A. Tutov V. V. Chernyshev 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(7):911-912
Tantalum oxide films with extended mesodefects (cracks) were prepared by electrochemical anodization with subsequent bending deformation. The dependences of the average width of cracks and their average concentration on the relative elongation are determined. 相似文献
8.
Optical properties of aluminum-doped zinc oxide films deposited by direct-current pulse magnetron reactive sputtering 下载免费PDF全文
A series of (103)-oriented aluminum-doped zinc oxide (AZO) films were deposited on glass substrates via direct- current pulse magnetron reactive sputtering at different O2-to-Ar gas flow ratios (GFRs). The optical properties of the films were characterized using the fitted optical constants in the general oscillator model (which contains two Psemi-Tri oscillators) through the use of measured ellipsometric parameters. The refractive index dispersion data below the interband absorption edge were analyzed using a single-oscillator model. The fitted optical energy gap obtained using the single- oscillator model clearly shows a blue shift, followed by a red shift, as the GFR increases from 0.9/18 to 2.1/18. This shift can be attributed to the change in the free electron concentration of the film, which is closely related to the film stress. In addition, the fitted β value indicates that the AZO film falls under the ionic class. The pbotoluminescence spectrum indicates a photoluminescence mechanism of the direct and wide energy gap semiconductor. 相似文献
9.
V. F. Surganov A. M. Mozalev N. I. Tatarenko V. A. Lastochkina 《Journal of Applied Spectroscopy》1998,65(2):206-210
The experimental specimens consisted of periodic columnar nanostructures of anodic titanium oxide (average dimension≈60 nm)
that were produced by anodic oxidation of the two-layer thin-film composition Ti−Al in a solution of oxalic acid that was
followed by vacuum annealing. The structures formed were studied by electron microscopy and reflection IR spectroscopy. It
is found that the nanodimensional columns consist predominantly of quasiamorphous Ti dioxide in the form of rutile and anatase
with minimum inclusions of Ti2O3 and TiO. Vacuum annealing decreases the content of TiO2 and increases that of Ti2O3 and TiO in the oxide columns. These changes characterize dissolution of oxygen from the composition of the columnar structures
in a residual film of metallic Ti.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 2, pp. 200–204, March–April, 1998. 相似文献
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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 相似文献
11.
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. 相似文献
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We investigate the resistive switching behaviour of a tantalum oxide nanolayer‐based nonvolatile memory with Pt/TaO5–x/TaN structure, which was prepared at room temperature through a processing compatible with CMOS technology. The tantalum oxide nanolayer with thickness of about 5 nm was fabricated by plasma oxidation of TaN films. The switching mechanism can be explained by the modulation of the local oxygen‐deficient conduction channel resulting from oxygen ions drift. This Letter represents a cost‐efficient method for developing nanoscale restive switching nonvolatile memories. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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采用溶胶-凝胶法在Pt/Ti/SiO2/Si衬底上制备了不同La掺杂浓度PLZT(x/40/60)薄膜- x射线衍射分析表明制备的PLZT(x/40/60)薄膜是具有单一钙钛矿结构的多晶薄膜- 通过红外椭圆偏振光谱仪测量了波长为2-5—12-6μm范围内PLZT薄膜的椭偏光谱,采用经典色 散模型拟合获得PLZT薄膜的红外光学常数,同时也拟合获得PLZT薄膜的厚度- 随着La掺杂浓 度的增大,折射率逐渐减小- 而消光系数除PLZT(4/40/60)薄膜外,呈现逐渐增大的趋势- 分析表明这些差异主要与PLZ
关键词:
PLZT薄膜
红外光学性质
红外椭圆偏振光谱 相似文献
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光谱椭偏仪被用来研究用脉冲激光沉积方法在Si(100)基片上,温度分别为400,500,600,700 ℃制备的ZnO薄膜的特性。利用三层Cauchy散射模型拟合椭偏参数,计算了每个温度下制备的ZnO薄膜在400~800 nm波长范围内的折射率(n)和消光系数(k)。发现基片温度对光学常数有很大的影响。通过分析XRD表征的晶体结构和 AFM表征的薄膜表面形貌,发现折射率的变化归因于薄膜堆积密度的变化。为了获得具有较好的光学和薄膜质量的ZnO薄膜,相比与其他沉积温度600 ℃或许是最佳的沉积温度。 相似文献
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采用红外椭圆偏振光谱对微波等离子体化学气相沉积法(MPCVD)和热丝化学气相沉积法(H-FCVD)制备的金刚石薄膜在红外波长范围(2.5—12.5μm)的光学参数进行了测量.建立了不同的光学模型,且在模型中采用Bruggeman有效介质近似方法综合考虑了薄膜表面和界面的椭偏效应.结果表明,MPCVD金刚石膜的椭偏数据在模型引入了厚度为77.5nm的硅表面氧化层、HFCVD金刚石膜引入879nm粗糙层之后能得到很好的拟合.最后对两种模型下金刚石薄膜的折射率和消光系数进行了计算,表明MPCVD金刚石薄膜的红外
关键词:
金刚石薄膜
红外椭圆偏振光谱
光学参数
有效介质近似 相似文献
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S. Feliu Jr. Ma.J. Bartolomé J.A. González V. López S. Feliu 《Applied Surface Science》2008,254(9):2755-2762
The paper studies some aspects of the behaviour of four aluminium alloys under chemical etching by sodium hydroxide solution and during their subsequent anodizing in sulphuric acid solution. A correspondence is seen between etching rate, thickness of the passivating oxide film and porosity of the anodic layer. The possibility of an influence on these properties of precipitates and micro-heterogeneities in the metallic surface is suggested. 相似文献
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对未经化学抛光处理的Al进行阳极氧化得到阳极氧化铝模板,发现Al表面形成了条纹与多孔阵列共存的自组织结构,用原子力显微镜对这种结构进行了研究.借助Brusselator模型对条纹的形成机理进行了讨论,认为条纹图案是Al表面氧化层/电解液界面的Al2O3在整个反应过程中的生成和溶解两个过程相互竞争导致的,只有在特定的反应条件才会出现高度有序的结构.
关键词:
氧化铝模板(AAO)
原子力显微镜(AFM)
自组织条纹
Brusselator模型 相似文献
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dc reactive magnetron sputtering technique was employed for deposition of tantalum oxide films on quartz and silicon substrates by sputtering of pure tantalum target in the presence of oxygen and argon gases under various substrate temperatures in the range 303-973 K. The variation of cathode potential with the oxygen partial pressure was systematically studied. The influence of substrate temperature on the chemical binding configuration, crystal structure and optical properties was investigated. X-ray photoelectron spectroscopic studies indicated that the films formed at oxygen partial pressures ≥1 × 10−4 mbar were stoichiometric. The Fourier transform infrared spectroscopic studies revealed that the films formed up to substrate temperatures <673 K showed a broad absorption band at 750-1000 cm−1 and a sharp band at 630 cm−1 indicated the presence of amorphous phase while at higher substrate temperatures the appearance of bands at about 810 and 510 cm−1 revealed the polycrystalline nature. The effect of substrate temperature on the electrical characteristics of Al/Ta2O5/Si structure was investigated. The dielectric constant values were in the range 17-29 in the substrate temperature range of 303-973 K. The current-voltage characteristics showed modified Poole-Frenkel conduction mechanism with a tendency for reduction of the compensation level. The optical band gap of the films decreased from 4.44 to 4.25 eV and the refractive index increased from 1.89 to 2.25 with the increase of substrate temperature from 303 to 973 K. 相似文献
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Optical absorbers find uses in a wide array of applications across the electromagnetic spectrum, including photovoltaic and photochemical cells, photodetectors, optical filters, stealth technology, and thermal light sources. Recent efforts have sought to reduce the footprint of optical absorbers, conventionally based on graded structures or Fabry‐Perot‐type cavities, by using emerging concepts in plasmonics, metamaterials, and metasurfaces. Unfortunately, these new absorber designs require patterning on subwavelength length scales, and are therefore impractical for many large‐scale optical and optoelectronic devices. In this article, we summarize recent progress in the development of optical absorbers based on lossy films with thicknesses significantly smaller than the incident optical wavelength. These structures have a small footprint and require no nanoscale patterning. We outline the theoretical foundation of these absorbers based on “ultra‐thin‐film interference”, including the concepts of loss‐induced phase shifts and critical coupling, and then review several applications, including ultra‐thin color coatings, decorative photovoltaics, high‐efficiency photochemical cells, and infrared scene generators.