非晶态Se薄膜的自发晶化研究

利用真空热蒸镀的方法制备了非晶Se薄膜,测试了稳定的非晶Se薄膜,不稳定的非晶Se薄膜和初始自发晶化的非晶Se薄膜的透射率光谱和拉曼光谱,对透射率光谱曲线进行了拟合,计算了薄膜的厚度和折射率随波长的变化关系。在自我晶化过程中,Se薄膜折射率逐渐增大;随波长增大,折射率则减小,初始自发晶体的Se薄膜中,出现标志Se8环和链的结构,不完整的环和链结构在自发晶化过程中得到了增强。     

锗薄膜透射光学二次谐波研究

本文采用固定入射角，改变入射光偏振方位角的方法从实验上了研究了锗薄膜的透射光学二次谐波产生及其变化规律，并从理论上推导了产生透射二次谐波的表达式，最后拟合求得描述面谐波电流的唯象参数ａ。     

Inversion of the Nonmonotonic Polarization Angular Dependence of the Coefficient of Light Reflection from a Thin Film on an Absorbing Substrate

Using computer simulation, it is shown that when light is incident obliquely upon a thin film with the frequency lying in a range of the longitudinal-transverse splitting of the resonant excitation of the substrate, it is possible to get a smooth inversion of the nonmonotonic angular dependence of the reflection coefficient for the s- and p-polarizations. It disappears upon suppression of multiple-beam interference in the layer or resonant excitation in the substrate.__________Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 2, pp. 277–279, March–April, 2005.     

Sum-Frequency Generation from a Thin Cylindrical Layer

In the Rayleigh–Gans–Debye approximation, we have solved the problem of the sum-frequency generation by two plane elliptically polarized electromagnetic waves from the surface of a dielectric particle of a cylindrical shape that is coated by a thin layer possessing nonlinear optical properties. The formulas that describe the sum-frequency field have been presented in the tensor and vector forms for the second-order nonlinear dielectric susceptibility tensor, which was chosen in the general form, containing chiral components. Expressions describing the sum-frequency field from the cylindrical particle ends have been obtained for the case of a nonlinear layer possessing chiral properties. Three-dimensional directivity patterns of the sum-frequency radiation have been analyzed for different combinations of parameters (angles of incidence, degrees of ellipticity, orientations of polarization ellipses, cylindrical particle dimensions). The mathematical properties of the spatial distribution functions of the sum-frequency field, which characterize the symmetry of directivity patterns, have been revealed.     

多偏振组合同时测量的高灵敏飞秒时间分辨和频光谱系统

Characterization of real-time and ultrafast motions of the complex molecules at surface and interface is critical to understand how interfacial molecules function. It requires to develop surface-sensitive, fast-identification, and time-resolved techniques. In this study, we employ several key technical procedures and successfully develop a highly sensitive femtosecond time-resolved sum frequency generation vibrational spectroscopy (SFG-VS) system. This system is able to measure the spectra with two polarization combinations (ssp and ppp, or psp and ssp) simultaneously. It takes less than several seconds to collect one spectrum. To the best of our knowledge, it is the fastest speed of collecting SFG spectra reported by now. Using the time-resolved measurement, ultrafast vibrational dynamics of the N-H mode of α-helical peptide at water interface is determined. It is found that the membrane environment does not affect the N-H vibrational relaxation dynamics. It is expected that the time-resolved SFG system will play a vital role in the deep understanding of the dynamics and interaction of the complex molecules at surface and interface. Our method may also provide an important technical proposal for the people who plan to develop time-resolved SFG systems with simultaneous measurement of multiple polarization combinations.     

Pattern Formation in a Thin Solid Film with Interactions

We investigate a new type of surface instability of a thin elastic film subjected to surface interactions such as van der Waals and electrostatic forces from another solid surface in its vicinity. It is found that a sufficiently soft (shear modulus <10 MPa) and nearly incompressible film deforms to form an undulating pattern without any mass transport. A novel feature is that the characteristic length scale of the pattern is nearly independent of the nature and magnitude of the external force, but varies linearly with the film thickness. These results explain some recent experiments and are applicable to problems such as adhesion and friction at soft solid interfaces, peeling of adhesives, patterning of solid surfaces, etc.     

Evolution of Magnetic Domain Structure in a YIG Thin Film

The evolution of a magnetic domain structure induced by temperature and magnetic field is reported in silicondoped yttrium iron garnet(YIG) films with perpendicular anisotropy.During a cooling-down procedure from300 K to 7K,a 20%change in the domain width is observed,with the long tails of the stripes being shortened and the twisting stripes being straightened.Under the influence of the stray field of a barium ferrite,the garnet presents an interesting domain structure,which shows an appearance of branching protrusions.The intrinsic mechanisms in these two processes are also discussed.     

Approximation in Thin Film Brick-Wall Model

The thin film brick-wall model is an important method on calculating the entropy of the non-static black hole. But we can see in this paper that the approximation used in the thin film brick-wall model is a rate of two infinitesimal parameters in fact. in this paper, we make an exact calculation of the approximation term and give the solution in the Schwarzschild black hole space-time.     

Determination of Thermal Diffusivity of a Manganite Thin Film

Thermal diffusivity has been investigated in a manganite thin film La0.6Sr0.4MnO3 by means of transient grating （TG） technique at room temperature. A new method, which is generalized to two-layered samples of the thin film deposited on a semi-infinite substrate, is established to fit the TG signals. The thermal diffusivity of the Lao.6Sro.4MnO3 thin film with a thickness of 200nm on an MgO （100） substrate is determined to be 0.92mm^2/s, which is slightly smaller than that of the single crystal sample （1 mm^2/s）.     

发光薄膜沉积技术中薄膜晶体管的优化设计

为了能制备高均匀性、大尺寸高清RGB-OLED显示终端,发展了一种全新的、无掩膜低成本的彩色薄膜沉积技术——薄膜晶体管导向的薄膜沉积技术,并研究了薄膜晶体管的宽长比及栅压对电聚合发光薄膜性能的影响,寻找最佳的制备条件。实验中采用像素尺寸大小为200μm×200μm的AMOLED基板,通过TFT来控制发光薄膜在ITO像素上的电化学聚合过程。首先对不同宽长比的TFT性能进行表征,再对不同宽长比的TFT在不同栅压条件下制备的电化学聚合薄膜进行表征和分析。实验结果表明,在同一宽长比的TFT控制下,施加栅压越大,制备的薄膜越厚,发光效果越好;在不同宽长比的TFT控制下,宽长比越大,聚合薄膜越厚,发光效果越好。在较大栅压下,选择宽长比为50μm/10μm的TFT最为适宜。研究结果为电化学聚合技术在AMOLED显示中的应用奠定了良好基础。     

Design of a Thin Film Infrared Barcode on a Flexible Substrate

We report the design, fabrication and characterization of an infrared barcode. This barcode is composed of a bilayer of titanium and amorphous silicon on a flexible Kapton substrate. Information encoded in the barcode shows high contrast when viewed with an infrared imaging system in the 8 to 12 m spectral region. The barcode information is concealed under visible viewing conditions, i.e., the barcode appears as an untreated, uniform metal sheet to a detector of visible radiation (400 to 700nm).     

纳米硅结构薄膜光致发光的温度依赖特性

综合考虑纳米硅结构薄膜的特殊性质,如量子限制效应、光学带隙和光跃迁振子强度对纳米硅粒径的依赖特性以及光学带隙和光辐射的温度依赖特性等,给出了一个解析表达式来分析具有一定粒径分布的纳米硅结构薄膜的光致发光(PL)强度分布,其中选取了两种纳米硅的粒径分布,即高斯分布和对数正态分布。结果表明,随着平均粒径和粒径分布偏差的减小,纳米硅薄膜的PL谱峰蓝移。随着环境温度的升高,纳米硅结构薄膜的PL谱峰红移且相对发光强度减弱。纳米硅结构薄膜光辐射拟合的结果与实验数据的比较分析表明,该模型能够很好地解释纳米硅结构薄膜在不同温度下的PL特性。     

Manipulating Nonlinear Photocurrent from Interlayer Coupling in Bilayer Metamaterials for Polarized Terahertz Generation

Polarized terahertz (THz) wave generation is of great significance for chiral and anisotropic sensing applications. However, how to manipulate amplitude, polarization, and ellipticity of the THz generation is still a fundamental challenge. Herein, polarized THz wave generation is achieved from a bilayer metamaterial consisting of T-shaped structure (TSS) and split resonator rings (SRRs) by combining Maxwell and hydrodynamic equations. The elliptically polarized THz wave can be synthetized directly from horizontally and vertically polarized THz components due to the orthogonal nonlinear photocurrents along the arm-directions of TSS and SRRs, respectively. Besides, the ellipticity and the orientation angle of the THz polarization ellipse can be modulated by the twist angle between the SRRs and TSS layers. The maximum ellipticity can reach 0.34 while the orientation angle is tunable from −0.45 to 0.48π by tuning the twist angle. This work proposes an interlayer coupling method for the polarized THz sources based on metamaterials in potential circular dichroism and chiral sensing applications.     

Second Harmonic Generation in Arrays of Nanoholes in a Silver Film

Journal of Experimental and Theoretical Physics - Specific features of optical second harmonic (SH) generation in arrays of chiral helical nanoholes in a silver film are studied experimentally. An...     

Plasma Processes in Activated Thin Film Deposition

This paper deals with plasma aspects in physical and chemical vapour deposition processes. A systematic representation of deposition methods is given and possibilities of plasma diagnostic are summerized. Characteristic parameters of electron kinetics (mean free paths, collision frequencies, energy distribution functions) and rate equations for calculation of particle densities are discussed for a plasma in plasma activated physical vapour deposition device. Theoretical results are compared with measurements (T_e, N_e, E_z) in the plasma of a TiN_x-deposition device with hollow cathode arc evaporator. Mechanism of plasma polymerisation is discussed. Results of experimental investigations of the plasma in an Ar-hexamethyldisiloxane D.C. low pressure glow discharge are presented and compared with results of modelling of this plasma taking into account direct-, stepwise- and Penning-ionization. The necessivity of knowledge of reactive cross sections for understanding of plasma assisted thin film formation processes is accentuated.     

亚酞菁薄膜的折射率和吸收特性

通过真空镀膜法在单晶硅片上制备了一种新的严酞菁（三硝基溴硼亚酞菁）薄膜,利用全自动椭圆偏振光谱仪研究了该薄膜的椭偏光谱,测量了其复折射率,复介电常数和吸收系数,估算了薄膜在窗口区域的俘获能级并对其吸收谱的成因作了分析。     

非晶铟镓锌氧薄膜晶体管钼/铜源漏电极的研究

针对非晶铟镓锌氧薄膜晶体管（a-IGZO TFT）的钼/铜源漏电极开展研究。实验证明,单层Mo源漏电极与栅绝缘层之间的粘附性好、表面粗糙度较小、电阻率较大,而单层Cu源漏电极与栅绝缘层之间的结合性差且Cu原子扩散问题严重、表面粗糙度较大、电阻率较小。为了实现优势互补,我们设计了双层Mo（20 nm）/Cu（80 nm）源漏电极,并采用优化工艺制备了包含该电极结构的a-IGZO TFT。器件具有良好的电学特性,场效应迁移率为 8.33 cm²·V^-1·s^-1, 阈值电压为6.0 V,亚阈值摆幅为2.0 V/dec,开关比为 1.3×10⁷,证明了双层Mo/Cu源漏电极的可行性和实用性。