Influence of a strong longitudinal static electric field on free carrier faraday effect in an n-type InSb at room temperature at submillimeter wave frequencies

The expression for free carrier Faraday rotation and for ellipticity , as the function of the applied parallel static electric field and static magnetic field for a given value of wave angular frequency and electron concentration N₀, are obtained and theoretically analyzed with the aid of one-dimensional linearized wave theory and Kane's non-parabolic isotropic dispersion law. It is shown that the maximum Faraday rotation occurs near the cyclotron resonance condition, which can be expressed as , where , , and . Here m^* and e denote the effective mass and charge of electron, respectively. _g is the forbidden bandgap of semiconductor. v₀ is the carrier drift velocity, which is a non-linear function of E₀ in high field condition. A possibility of a simple way of determining the non-linear v₀ vs E₀ characteristics of semiconductors by the measurement of Faraday rotation is also discussed.     

超薄型平行平面镜的研制

超薄型平行平面镜的加工难度很高,往往在投入大量的辅助工装和较长的加工工时后,收效甚微。笔者用双平面分离器和平面环抛法相结合的工艺手段,经反复实践和试验,终于研制出厚度与直径的比例达1∶85、N=2、ΔN=0.2、θ=15″的平行平面镜。     

SbxSn1-xO2固溶体系电学性能与导电机制研究

本文报道以均匀共沉淀法制得Sb_xSn_1-xO₂体系半导体气敏材料,研究了固溶体组成与电导的变化规律,并对导电机制进行了讨论。结果表明:x<0.30时均可生成固溶体。微量Sb(x=0.04)的掺入即能提高SnO₂电导一个数量级,在x≤0.04区间电导都呈上升趋势,其后一直到固溶范围内随着X增加,电导反而缓慢下降。根据体系中存在的Sb°_Sn和Sb′_Sn两种缺陷,讨论了其电导变化和导电机制。认为平衡Sb°_Sn+2e′=Sb′_Sn对上述导电机制起决定作用。XPS分析对Sb⁵⁺、Sb³⁺的含量进行了确认,交流阻抗谱的测试结果从另一角度对电导行为加以证实。     

The second harmonic generation in semiconductors in the DC magnetic field

The second harmonic radiation in millimeter wave region is found in semiconductors in the absence of the dc electric field. The observed resonant maximum of radiation intensity is shown to be related to the excitation of the free-electron plasma oscillations in the dc magnetic field.     

NiO-MoO3/SiO2光催化剂的结构与光吸收性能

采用表面改性法制备了负载型复合半导体NiO-MoO3/SiO2, 用程序升温还原、 X射线衍射、 拉曼光谱、 透射电镜、 比表面积测定和紫外-可见光漫反射光谱技术对固体材料的组成结构和光吸收性能进行了表征. 结果表明, NiO-MoO3/SiO2的平均粒径约为10 nm, 在载体表面存在xNiO·MoO3复合氧化物的微晶, NiO和MoO3在固体材料表面产生相互修饰作用. NiO的加入有助于提高MoO3在载体SiO2表面的分散程度, 抑制MoOx的聚合, 减小微晶尺寸, 而且可以增强固体材料的光吸收性能, 提高复合半导体对光能的利用率.     

TDDFT-SOS Studies on the Polarizabilities and Second-order Hyperpolarizabilities of Zn_3O_3 II-VI Semiconductor Clusters

1 INTRODUCTION II-VI semiconductor materials with ZnO as the representative possess wide forbidden gaps and high exciton binding energy, which have paved the way for the study of exciton characters and short wave photo-conducting devices. They present wide appli- cations, such as ultraviolet laser transmitting device, piezoelectric device, optical waveguild and high efficient quantum dot luminous apparatus[1～8]. Re- cently, II-VI semiconductor cluster materials with nano-structure ha…     

Influence of photostabilizers on wood flour-HDPE composites exposed to xenon-arc radiation with and without water spray

The weathering of wood-plastic composites changes their appearance and/or mechanical properties. These changes can be slowed through the addition of ultraviolet absorbers and pigments. The first phase of this study examined the effect of incorporating different concentrations of an ultraviolet absorber and/or pigment into wood-flour-filled high-density polyethylene (WF/HDPE) composites. Lightness and flexural properties of the composites were determined periodically during exposure to UV radiation and water spray in a xenon-arc type weathering apparatus. The influence of exposure type (UV radiation, with or without water spray) on the properties of photostabilized WF/HDPE composites was determined in the second phase of the study. The results showed that both ultraviolet absorbers and pigments provide protection against weathering of wood-plastic composites. The amount of protection can be influenced by both photostabilzer concentration and exposure variables.     

被动调Q激光器优化的研究

被动调Q激光器以其结构简单、紧凑而获得了广泛的应用。为优化其性能参数,在总结近些年被动调Q基本理论基础上,对于具有能量上转换(Energy-transfer upconversion)的激光工作物质构成的被动调Q激光器,提出了可以将能量上转换引起的损耗归到线性损耗中进行优化设计的方法,并给出了输出镜的反射率和饱和吸收体的小信号透过率两者优化选择的直接关系图。根据被动调Q激光器的特有参数α,在总结提高调Q峰值功率的方法基础上,得出当α接近无穷大时,从被动调Q过渡到主动调Q,实现了被动调Q和主动调Q理论的统一。     

Thermo-electric charge-to-voltage converter with superconductor–insulator–normal tunnel junction for bolometer applications

A novel type of the zero-biased thermo-electric bolometer (TEB) is proposed. The bolometer is based on a charge-to-voltage converter (CVC) with a superconductor–insulator–normal (SIN) tunnel junction and a superconducting absorber. The absorption of photons in the absorber leads to excitation of quasiparticles with some fraction of charge imbalance, tunneling through the SIN junction in zero-biased mode and generation of voltage. The thermoelectric voltage is determined by accumulation of tunneling charge in an external capacitance. Conversion efficiency is very high and voltage values comparable with a superconducting gap are easily achieved. The zero-biased CVC–TEB can be effectively used for creation of an array of bolometers and multi-pixel detection systems.     

Naphthodithiophene‐Diketopyrrolopyrrole‐Based donor–Acceptor alternating π‐Conjugated polymers for Organic thin‐Film transistors

Novel naphtho[1,2‐b:5,6‐b′]dithiophene (NDT) and diketopyrrolopyrrole (DPP)‐containing donor‐acceptor conjugated polymers (PNDTDPPs) with different branched side chains were synthesized via Pd(0)‐catalyzed Stille coupling reaction. Octyldodecyl (OD) and dodecylhexadecyl (DH) groups were tethered to the DPP units as the side chains. The soluble fraction of PNDTDPP‐OD polymer in chloroform has much lower molecular weight than that of PNDTDPP‐DH polymer. PNDTDPP‐DH polymer bearing relatively longer DH side chains exhibited much better charge‐transport behavior than PNDTDPP‐OD polymer with shorter OD side chains. The thermally annealed PNDTDPP‐DH polymer thin films exhibited an outstanding charge carrier mobility of ～1.32 cm² V^?1 s^?1 (I_on/I_off ～ 10⁸) measured under ambient conditions, which is almost six times higher than that of thermally annealed PNDTDPP‐OD polymer thin films. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 5280–5290