Rui Ding Chunxiang Xu Baoxiang Gu Zengliang Shi Haitao Wang Long Ba
材料科学技术（英）
Well-crystallized MgZnO alloy thin films with hexagonal wurtzite structure were fabricated by sol-gel method. With the band gap increases, the surface roughness and the grain size reduces. It is worth noting that the intensity of the band-edge luminescence of Mg doped films enhances with the increase of the Mg content. The microstructure and photoluminescence mechanism have been discussed based on X-ray diffraction patterns, atomic force microscopy images, ultraviolet-visible absorption spectra, photoluminescence spectra and Fourier transform infrared spectra.
关键词:
null
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Optical properties
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Sol-gel method
Sushant K Rawal
材料科学技术（英）
The objective of the present work is to investigate the effect of various sputtering parameters such as nitrogen flow rate, deposition time and sputtering pressure on structural, wettability and optical properties of titanium oxynitride films deposited on glass substrate by reactive magnetron sputtering. The X-ray diffraction graphs of titanium oxynitride films show evolution of various textures of TiOxNy and TiN phases with increasing nitrogen flow rate and deposition time, but an increase in sputtering pressure from 4.0 to 8.0 Pa results in decline of various textures observed for TiOxNy and TiN phases. The stress and strain calculated by sin2Ψmethod are compressive, which decrease with increasing nitrogen flow rate from 55 to 100 sccm (standard cubic centimeter per minute) and increase with increasing deposition time from 80 to 140 min due to atomic penning effect and increasing thickness of the deposited films. The titanium oxynitride films have contact angle values above 90 deg., indicating that films are hydrophobic. The maximum contact angle of 109.1 deg. is observed at deposition time of 140 min. This water repellent property can add value to potential protective, wear and corrosion resistant application of titanium oxynitride films. The band gap decreases from 1.98 to 1.83 eV as nitrogen flow rate is increased from 55 to 100 sccm; it decreases from 1.93 to 1.79 eV as deposition time is increased from 80 to 140 min as more nitrogen incorporation results in higher negative potential of valence band N2p orbital. But it increases from 2.26 to 2.34 eV for titanium oxynitride films as sputtering pressure increases from 4.0 to 8.0 Pa.
关键词:
Titanium oxynitride
Tammy Y.Olson
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Jin Z.Zhang
材料科学技术（英）
Nanomaterials possess intriguing optical properties that depend sensitively on size, shape, and material content of the structures. Controlling such structural characteristics of the nanostructures allows the tailoring of their physical and chemical properties, e.g. optical, electronic, and catalytic, to achieve what is desired for specific applications of interest. This review will cover the development of various shapes for silver and gold nanomaterials with emphasis on their relation to optical properties. Examples of various modern synthetic methods and characterization techniques are highlighted. The influence of the metal nanomaterial′s shape and optical absorption on surface enhanced Raman scattering (SERS) and a final note on new emerging applications of metal nanostructures are also discussed.
关键词:
Nanomaterial
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null
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null
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null
Haiping XIA
,
Zhaoyang JIANG
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Jianli ZHANG
,
Jinhao WANG
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Yuepin ZHANG
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Qiuhua NIE
材料科学技术（英）
Water soluble fullerenols were synthesized and incorporated in SiO2, SiO2-TiO2, GPTMS- SiO2, GPTMS-ATPS inorganic and organic-inorganic materials by sol-gel processes. The maximum concentrations of C60 (OH) n and C70 (OH) n in the obtained SiO2 gels were estimated to be about 0.6% and 1.5% in weight, respectively. The characteristics of the UV/visible spectra of fullerenols in H2O and various gels were measured and compared. The thermal stability of fullerenols in gels was investigated with differential thermal analysis (DTA). The results indicate that the absorption features of fullerenols in solid gels are similar to those in H2O and the fullerenols in SiO2 are stable at 400ºC. The optical limiting effect of the fullerenols was investigated preliminarily.
关键词:
Water soluble fullerenol
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null
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null
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null
Yuying HAO
,
Bingshe XU
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Zhixiang GAO
,
Hua WANG
,
Hefeng ZHOU
,
Xuguang LIU
材料科学技术（英）
A new electroluminescent material, salicylaldehyde anil zinc (SAZ) was synthesized, which can form high quality, thermal stability, nano-scale amorphous films by vacuum evaporation. Its structure, thermal stability were characterized by infrared (IR) spectra, differential thermal analysis-thermogravimetry (DTA-TG) analysis, respectively. The optical properties of SAZ were investigated by UV absorption spectra, Photoluminescence (PL) excitation and emission spectra. The highest occupied molecular orbits (HOMO), lowest unoccupied molecular orbits (LUMO) and optical band gap were evaluated by cyclic voltammetry curve and optical absorption band edge. The electroluminescent devices using SAZ as the emissive layer emit green light with a peak wavelength at 509 nm and a brightness of about 3.1 cd/m2.
关键词:
Salicylaldehyde anil zinc
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光学性质
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电子能级结构
Z.El-Gohary
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A.Abdel-Aal
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A.Elshafie
材料科学技术（英）
Several thin films of Te10Ge10Se77Sb3 chalcogenide glass of different thicknesses (250nm to 400nm) were prepared by thermal evaporation under vacuum of 133 ×10-6 Pa(10-6torr). X- ray diffraction analysis showed the amorphicity of the prepared films which become partially crystalline by annealing. Transmittance and reflectance measurements in the spectral range of 200nm to 2500nm have been carried out at normal incidence. The analysis of the absorption coefficient data showed the existence of indirect transition for the photon energy E in the range 1-3eV and direct transition for E>3eV. From the determination of the optical constants (n, k), the dispersion of the refractive index has anomalous behaviour in the region of the fundamental absorption edge, and followed by the single- effective oscillator approach.The investigated optical parameters such as the optical energy gap Eopt, the high frequency dielectric constant eoo ,the oscillator position lo, and the oscillator strength So, were significantly affected by the film thickness. The characteristic energy gap obtained from the conductivity measurements is nearly half the value of that obtained from the optical data as in the case of thickness 400nm. The activation energy is 0.65 eV and the indirect optical gap is 1.32eV.
关键词:
Chalcogenide glasses
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null
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