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optical properties of hexagonal boron nitride thin films deposited by radio frequency bias magnetron sputtering

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Chinese Physics B 2009年第9期18卷 4013-4018页

作者：邓金祥张晓康姚倩汪旭洋陈光华贺德衍 School of Applied Mathematics and Physics Beijing University of Technology School of Physical Science and Technology Lanzhou University

The optical properties of hexagonal boron nitride （h-BN） thin films were studied in this paper. The films were characterized by Fourier transform infrared spectroscopy, UV-visible transmittance and reflection spectra, h-BN thin films with a wide optical band gap Eg （5.86 eV for the as-deposited film and 5.97 eV for the annealed film） approaching h-BN single crystal were successfully prepared by radio frequency （RF） bias magnetron sputtering and post-deposition annealing at 970 K. The optical absorption behaviour of h-BN films accords with the typical optical absorption characteristics of amorphous materials when fitting is made by the Urbach tail model. The annealed film shows satisfactory structure stability. However, high temperature still has a significant effect on the optical absorption properties, refractive index n, and optical conductivity σ of h-BN thin films. The blue-shift of the optical absorption edge and the increase of Eg probably result from stress relaxation in the film under high temperatures. In addition, it is found that the refractive index clearly exhibits different trends in the visible and ultraviolet regions. Previous calculational results of optical conductivity of h-BN films are confirmed in our experimental results.

关键词： hexagonal boron nitride films sputtering UV-visible optical properties

optical properties and local structure of Dy^(3+)-doped chalcogenide and chalcohalide glasses

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Journal of Rare Earths 2008年第6期26卷 889-894页

作者：唐高杨志勇罗澜陈玮 Shanghai Institute of Ceramics Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences

Dy^3＋-doped Ge-Ga-Se chalcogenide glasses and GeSe2-Ga2Se3-CsI chalcohalide glasses were prepared. The absorption, emission properties, and local structure of the glasses were investigated. When excited at 808 nm diode laser, intense 1.32 and 1.55 μm near-infrared luminescence were observed with full width at half maximum （FWHM） of about 90 and 50 nm, respectively. The lifetime of the 1.32 μm emission varied due to changes in the local structure surrounding Dy^3＋ ions. The longest lifetime was over 2.5 ms, and the value was significantly higher than that in other Dy^3＋-doped glasses. Some other spectroscopic parameters were calculated by using Judd-Ofelt theory. Meanwhile, Ge-Ga-Se and GeSe2-Ga2Se3-CsI glasses showed good infrared transmittance. As a result, Dy^3＋-doped Ge-Ga-Se and GeSe2-Ga2Se3-CsI glasses were believed to be useful hosts for 1.3 μm optical fiber amplifier.

关键词： chalcogenide glass chalcohalide glass optical properties microstructure 1.3 μm optical fiber amplifier rare earths

optical properties of anatase and rutile TiO2 studied by GGA+U

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Chinese Physics B 2017年第8期26卷 370-375页

作者：李金平孟松鹤秦丽媛陆汉涛 Center for Composite Materials and Structures Harbin Institute of Technology Yukawa Institute for Theoretical Physics Kyoto University Center for Interdisciplinary Studies & Key Laboratory for Magnetism and Magnetic Materials (Ministry of Education) Lanzhou University

The optical properties of thermally annealed TiO_2 samples depend on their preparation process, and the TiO_2 thin films usually exist in the form of anatase or rutile or a mixture of the two phases. The electronic structures and optical properties of anatase and rutile TiO_2 are calculated by means of a first-principles generalized gradient approximation（GGA）＋U approach. By introducing the Coulomb interactions on 3d orbitals of Ti atom（U^d） and 2p orbitals of O atom（U^p）, we can reproduce the experimental values of the band gap. The optical properties of anatase and rutile TiO_2 are obtained by means of the GGA＋U method, and the results are in good agreement with experiments and other theoretical data. Further, we present the comparison of the electronic structure, birefringence, and anisotropy between the two phases of TiO_2. Finally,the adaptability of the GGA＋U approach has been discussed.

关键词： TiO2 first-principles GGA+U electronic structure optical properties

optical properties of cobalt xanthate films on different substrates

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International Journal of Minerals,Metallurgy and Materials 2014年第7期21卷 736-740页

作者： I.A.Kariper T.zpozan Education Faculty Erciyes University Chemistry Department Science FacultyErciyes University

Cobalt isopropyl xanthate thin films （CXTFs） were deposited via chemical bath deposition onto different substrates：commercial glass （CG）, indium tin oxide （ITO）, and poly（methyl methacrylate）（PMM）. Isopropyl xanthate was synthesized according to a method described in the literature. The cobalt nitrate and isopropyl xanthate were mixed in a beaker, which allowed the thin films to be deposited via a simple ion-ion mechanism. The transmission, reflectivity, refractive index, dielectric constant, and optical conductivity were investigated for various thin films coated onto different substrates. An ultraviolet-visible spectrophotometer was used to measure the optical properties of the thin films. The lowest value of the transmission and the highest value of the refractive index were observed for the thin films deposited onto PMM. The structure of the cobalt xanthate was characterized by Fourier transform infrared （FTIR） spectroscopy, which was measured using a Perkin-Elmer Spectrum 400 spectrometer. The stretching vibration of the Co-S bonds was observed at 359 cm^-1 in the FTIR spectrum of the CXTFs.

关键词： thin films cobalt compounds xanthates chemical deposition optical properties

optical properties of CeO_2/Fe_3O_4 solar control glass coating

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Rare Metals 2006年第z1期25卷 351-354页

作者： ZHAO Hongsheng LIU Bing HU Hongpo LI Ziqiang SHAO Youlin Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China

A cerium-iron oxide solar control coating on glass was prepared by citric acid sol-gel method, dip-coating techniques and proper heat treatment process. Results show that the cerium-iron glass coating is composed of nanocrystalline CeO2, Fe2O3, and nano holes. The cerium-iron glass coating has high transmittance in visible light, low UV and near IR transmittance. The wavelength of absorption edge for most glass coating has an obvious redshift to about 375 nm. There exist a wide absorption band at the range of 800-1600 nm and high transmittance at the wavelength from 400 nm to 800 nm, and the solar energy and visible transmittances are 50% and 65%, respectively. It ascribes to the high content of trivalence cerium and bivalence iron ions in the cerium/iron coating. It is indicated that this kind of glass coating has very good UV-sheering and heat-insulating property, can be used as an effective solar control glass in automobile and architecture.

关键词： solar control glass coating sol-gel method optical properties

optical properties of rubrene thin film prepared by thermal evaporation

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Chinese Physics B 2015年第4期24卷 451-455页

作者：陈亮邓金祥孔乐崔敏陈仁刚张紫佳 College of Applied Sciences Beijing University of Technology

Rubrene thin films are deposited on quartz substrates and silver nanoparticles （Ag NPs） films by the thermal evapo- ration technique. The optical properties of rubrene thin film are investigated in a spectral range of 190 nm-1600 nm. The analysis of the absorption coefficient （a） reveals direct allowed transition with a corresponding energy of 2.24 eV. The photoluminescence （PL） peak of the mbrene thin film is observed to be at 563 nm （2.21 eV）. With the use ofAg NPs which are fabricated by radio-frequency （RF） rnagnetron sputtering on the quartz, the PL intensity is 8.5 times that of as-deposited rubrene thin film. It is attributed to the fact that the surface plasmon enhances the photoluminescence.

关键词： rubrene optical properties photoluminescence surface plasmon enhancement

optical properties of polymer poly(phthalazinone ether sulfone ketone)film waveguide

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Chinese Optics Letters 2008年第1期6卷 74-75页

作者：滕婕宋媛蹇锡高赵明山 School of Physics and Optoelectronic Technology.Dalian University of Technology Department of Polymer Science & Materials.Dalian University of Technology

The optical properties of novel polymer poly（phthalazinone ether sulfone ketone, PPESK） film waveguide are studied by prism coupler. The optical properties of PPESK-8020, including refractive index, birefringence, thermo-optical coefficient and optical loss, are demonstrated. This kind of material has the advantages of low optical loss （less than 0.24 dB/cm at 1310 nm and 0.52 dB/cm at 1550 nm） and high thermal stability （1% weight loss temperature： 488 ℃）. Due to these excellent properties, it may have great potential in optical waveguide applications.

关键词： Birefringence optical properties optical waveguides Refractive index Thermodynamic stability

optical properties of 1.3-μm InAs/GaAs quantum dots grown by metal organic chemical vapor deposition

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Chinese Optics Letters 2009年第8期7卷 741-743页

作者：李林刘国军李占国李梅王晓华曲轶薄报学 National Key Lab of High Power Semiconductor Lasers Changchun University of Science and Technology

The optical properties of self-assembled InAs quantum dots （QDs） on GaAs substrate grown by metalorganic chemical vapor deposition （MOCVD） are reported. Photoluminescence （PL） measurements prove the good optical quality of InAs QDs, which axe achieved using lower growth temperature and higher InAs coverage. At room temperature, the ground state peak wavelength of PL spectrum and full-width at half-maximum （FWHM） are 1305 nm and 30 meV, respectively, which are obtained as the QDs are finally capped with 5-nm In0.06Ga0.94As strain-reducing layer （SRL）. The PL spectra exhibit two emission peaks at 1305 and 1198 nm, which correspond to the ground state （GS） and the excited state （ES） of the QDs, respectively.

关键词： Emission spectroscopy Gallium Gallium alloys Ground state Indium arsenide Industrial chemicals Metallorganic chemical vapor deposition optical properties Organic chemicals Organometallics Semiconducting indium Vapors

optical properties, Electronic Energy Level Structure and Electroluminescent Characteristics of Salicylaldehyde Anil Zinc

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Journal of Materials Science & Technology 2006年第2期22卷 225-229页

作者： Yuying HAO Bingshe XU Zhixiang GAO Hua WANG Hefeng ZHOU Xuguang LIU Department of Physics Taiyuan University of Technology Taiyuan 030024 China College of Materials Science and Engineering Taiyuan University of Technology Taiyuan 030024 China College of Chemical Engineering and Technology Taiyuan University of Technology Taiyuan 030024 China

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/m^2.

关键词： Salicylaldehyde anil zinc optical properties Electronic energy level structure Electroluminescence