Crystal structure and optical absorption investigations on β-In2S3 thin films

The crystal structure of annealed β-In₂S₃ thin films with different thickness was investigated by X-ray diffraction technique. Lattice parameters, crystallite size and microstrain were calculated. It was found that the lattice parameters are independent on film thickness, while annealing temperatures increase them. Crystallite sizes were increased with the increase of the film thickness and improved by annealing temperatures. In all cases, the microstrains were decreased gradually with the increase in both film thickness and annealing temperatures. Optical properties of β-In₂S₃ thin films were performed in the spectral range from 400 to 2500 nm to determine the optical constants (n and k), the high frequency dielectric constant, ε_∞, the lattice dielectric constant, ε_L, and the energy gap. The optical constants were found to be independent on film thickness in the range from 200 to 630 nm. The high frequency dielectric and lattice dielectric constants of the as-deposited film increased by annealing temperatures. The energy gap for the as-deposited In₂S₃ was found to be 2.60 eV and increased to 2.70 and 2.75 eV by annealing at 423 and 473 K for 1 h, respectively.     

Dispersive optical constants of thermally deposited AgIn5S8 thin films

AgIn₅S₈ thin films were obtained by the thermal evaporation of AgIn₅S₈ crystals onto ultrasonically cleaned glass substrates. The films are found to exhibit polycrystalline cubic structure. The calculated lattice parameter of the unit cell (a) is 10.78 Å. The transmittance data of the as grown films which was recorded at 300 K in the incidence wavelength (λ) range of 320-1000 nm are used to calculate the refractive, n(λ). The transmittance and reflectance data are also used to calculate the absorption coefficient of the as grown AgIn₅S₈ thin films. The fundamental absorption edge is found to be corresponding to a direct allowed transitions energy band gap. This band-to-band transition energy is found to be 1.78 eV and it is consistent with that reported for AgIn₅S₈ single crystals.     

Influence of Hf→Zr substitution on optical and refractometric parameters of Hf1−xZrxO2 thin films

Ellipsometric and spectroscopic investigations of Hf_1−xZr_xO₂ thin films were performed. Dispersion dependences of refractive indices and extinction coefficients in the wavelength interval 0.2-0.7 μm were obtained by optical-refractometric synthesis of absorption spectra. Optical-refractometric relation is applied to describe the dispersion of the refractive indices. Compositional behaviour of optical pseudogap and refractive indices of HfO₂-ZrO₂ thin films is studied.     

Hemispherical and diffuse reflectance and transmittance of a slightly inhomogeneous film bounded by rough, unparallel interfaces

The optical reflectance and transmittance of an ideal thin film are calculated in a well-known way. As far as a non-ideal thin film is concerned - i.e., a slightly inhomogeneous thin film bounded by rough, unparallel interfaces - three categories of spectral coefficients can be defined, i.e.: specular reflectance and direct transmittance (light intensity flux along the optical axis), hemispherical reflectance and transmittance (light intensity flux integrated over the solid half angle π), and diffuse reflectance and transmittance (light intensity flux scattered around the optical axis) coefficients. In this paper a model recently introduced for the specular and direct coefficients is generalized to calculate also the hemispherical and diffuse coefficients of a non-ideal film.     

论"温韦"的词风差异及其形成原因

温庭筠、韦庄同属花间词派作家,被人们并称为“温韦”,实际上他们的作品代表着两种不同的风格。论述了两人词风的差异及其形成原因。     

Optical constants and band edge of amorphous zinc oxide thin films

The optical characteristics of amorphous zinc oxide (a-ZnO) thin films grown by radio frequency reactive magnetron sputtering on various substrates at temperature < 325 K have been investigated in the spectral range 340-1600 nm. The amorphous nature of the a-ZnO films was verified by X-ray diffraction and the optical constants were obtained by analysis of the measured ellipsometric spectra using the Cauchy-Urbach model. Refractive indices and extinction coefficients of the films were determined to be in the range 1.67-1.93 and 3.9 × 10^− 8-0.32, respectively. The band edge of the films on Si (100) and quartz has been determined by spectroscopic ellipsometry (3.39 ± 0.05 eV) and spectrophotometric (3.35 ± 0.05 eV) methods, respectively. From the angle dependence of the p-polarized reflectivity we deduce a Brewster angle of 60.5°. Measurement of the polarized optical properties shows a high transmissivity (81%-99%) and low absorptivity (< 5%) in the visible and near infrared regions at different angles of incidence. Also, we found that there was a higher absorptivity for wavelength < 370 nm. This wavelength, ∼ 370 nm, therefore indicated that the band edge for a-ZnO thin films is about 3.35 eV.     

Infrared spectroscopic ellipsometry and atomic force microscopy study of plasma polymerized hexamethyldisiloxane layers post-treated by NH3 plasma

Hexamethyldisiloxane polymer layers obtained at low frequency glow discharge were post-treated by ammonia vapours under the same plasma conditions. Infrared spectroscopic ellipsometry and atomic force microscopy studies were carried out with the aim to elucidate the structural and morphological changes accompanying this modification. The infrared ellipsometry combined with best-fit calculations was used to evaluate the optical constants of the polymer film before and after the treatment, and thus to provide data for the vibrational band analysis. No additional modified layer due to the plasma treatment was detected, but a newly emerged weak band at 1562 cm⁻¹ was observed in the ellipsometric spectra of the ammonia-treated sample, which was ascribed to N-H deformation in amines.The surface morphology was imaged by atomic force microscopy. The data revealed that the NH₃ treatment had caused distinct micro-structural modification on the top layer surface. The size of the nodule aggregates was largely reduced and this contributed to a much better developed top surface.     

First-principles study on electronic structures and absorption spectra for BaWO4 crystal containing barium vacancy

The electronic structures, dielectric function and absorption spectra for the perfect BaWO₄ (BWO) crystal and the BWO crystal containing barium vacancy () have been studied using density functional theory code CASTEP with the lattice structure optimized. The results indicate that the optical properties of the BWO crystal exhibit anisotropy and its optical symmetry coincide with lattice structure geometry of the BWO crystal. For the BWO crystal containing , there exhibit four absorption bands peaking at 0.71 eV (1751 nm), 1.85 eV (672 nm), 3.43 eV (362 nm) and 3.85 eV (322 nm), respectively. The origins of the 370 nm absorption band should be related to the .     

二晏研究百年回顾与展望

百年来的二晏研究所取得的成果,不管是从数量上看还是从质量上看都是引人注目的,这些成果主要表现在二晏生平思想的研究和二晏文学作品的研究;然而其依然在六个方面存在着遗憾和不足。为了更好地推动下一步的更深入一层的研究,因此很有必要对二晏研究进行回顾和总结。     

词的体式与分类

按照词的音乐文学性质,可以把词分为单曲与套曲两大类。单曲从体段来说可以分为单调、双调、三叠、四叠四种类型;套曲则可以根据其体制特点及固有名称,分为联章、转踏、大曲、鼓子词、诸宫调等各种类型。采用这种二分法来谈词的体制,有助于突破只知单曲词不知成套词的惯常认知模式,全面把握词的艺术风貌与传播形式,回复其音乐文学样式的本来面目。