聚苯胺功能化的塑料光纤传感器用于黄曲霉毒素B1浓度检测

为开发低成本高灵敏度黄曲霉毒素B₁(AFB₁)检测设备,研制了一种将聚苯胺(PAni)与塑料光纤(POF)相结合的增敏光纤免疫传感器。传感器功能化设计采用两步法,首先将PAni涂层修饰至光纤传感区,然后通过戊二醛的交联作用,将AFB₁抗体分子固定于传感区。由于测量过程中抗原和抗体的免疫反应会导致POF表面折射率发生变化,从而引起探测光子数的波动,以此实现对AFB₁浓度的检测。实验研究了PAni涂层对传感器的增敏效果,结果表明PAni功能化的POF传感器增敏效果明显,且在0.01～10μg/L AFB₁浓度范围内,传感器的光子数变化量与AFB₁浓度间具有线性关系,检测限为0.53μg/L,加标回收率为95.97%～113.13%,且传感器对AFB₁的特异性和抗干扰性良好,满足AFB₁精量化检测的需要。     

Electrical and optical properties of copper indium ditelluride crystals grown from near-stoichiometric compositions

CuInTe₂ crystals grown by zone-leveling of nominally stoichiometric material are highly p-type. The net acceptor density is reduced by in-diffusion of zinc which acts as a donor impurity. Zinc-annealed crystals transmit in the infrared and exhibit an absorption edge at 0.92 eV.     

Temperature variation of optical energy gap values of the compound CuGaTe2

Measurements of optical absorption in the temperature range 20 to 300K were made on polycrstalline samples of the compound CuGaTe₂. These results were used to determine values of the optical energy gap E_g as a function of temperature T. The resulting curves of E_g vs T were fitted to a simplified Manoogian-Leclerc equation and the fitted coefficients used to give values of (dE_g/dT)₁ and (dE_g/dT)₂, due to lattice dilation and electron-phonon contributions, respectively. Hence, the deformation potentials of the valence and conduction bands were estimated for the present compound.     

一种基于Pd-Y合金纳米膜的光纤H2传感器

为提高光纤H₂传感器的响应速度、稳定性和可 重 复性,本文分析了Pd-H传感机理,进而提出利用双靶溅射工艺在石英光学玻璃基底上制 备55nm厚的Pd-Y合金H₂敏薄膜,采用双光路 检测技术设计并实现了反射式光纤束H₂传感器系统。通、放H₂实验结果表明,本文 研制的基于Pd-Y合金纳米薄膜的 传感器具有响应快速的特点,特别是在多次循环老化实验后表现出良好的稳定性和可重复性 。     

用热蒸发法制备的Cu2ZnSnS4 薄膜的光电性能

在室温下用真空热蒸发法在玻璃基片上制备Sn/Cu/ZnS 前躯体膜层,然后对其在550C 下在硫气氛中硫化3小时以制得Cu₂ZnSnS₄ (CZTS) 多晶薄膜。对该薄膜进行X射线衍射（XRD）、能量色散X射线光谱（EDX）、紫外可见近红外分光光度计、霍尔测量系统和3D光学显微镜等分析测试。实验结果表明,当[Cu]/([Zn] [Sn]) =0.83和[Zn]/[Sn] =1.15时,该CZTS薄膜在光子能量范围在1.5 - 3.5 eV 时其吸收系数大于4.010₄cm_-1 ,直接带隙为1.47 eV。其载流子浓度、电阻率和迁移率分别为7.9710₁₆ cm_-3, 6.06 Ω.cm, 12.9 cm₂/(V.s), 导电类型为p型。因此,所制备出的CZTS 薄膜适合作为太阳电池的吸收层材料。     

Free carrier optical absorption at 10.6 μm in GaAs

Optical absorption measurements at 10.6 μm have been perfor-med in chromium doped GaAs samples using a calorimetric tech-nique at 300 K, and an optical system to determine the varia-tion of the absorption versus temperature between 300 K and 650 K. Hall effect measurements have also been carried out in the same temperature range. The optical absorption cross sec-tion for both electrons and holes are discussed and experi-mentally determined. A semi-empirical formula is deduced which permit the calculation of the 10.6 μm free carrier absorption at any temperature and doping level provided the electron mobility is known. Besides free carrier and multi-phonon absorption another mechanism must be considered to explain the experimental data. Possible effect of small pre-cipitates is discussed.     

二氧化钛掺杂系统的电子结构和光学性质的研究

采用总能量平面波赝势方法研究了Sc掺杂、含氧空位、氧空位与Sc掺杂共存时的锐钛矿TiO2系统的电子结构和光学性质。结果表明,Sc掺杂对系统的主要贡献在价带区,在可见光区有明显的光吸收;氧空位可以使系统发生莫特相变,系统在可见光区也有较强的吸收;氧空位与Sc掺杂共存时系统在可见光区的吸收相干加强。     

Losses in tantalum pentoxide waveguides

Thin films of tantalum pentoxide for possible use as waveguides have been prepared by reactive sputtering and by thermal and anodic oxidation of sputtered tantalum films. Measurements have been made of the losses in these films for different guided modes. These results have been analyzed to determine the loss mechanism. The losses do not fit the Rayleigh scattering theory precisely and the deviation is attributed to absorption by impurities at the surface as well as in the bulk. The effects of bulk and surface loss mechanisms have been obtained and causes of these are discussed.     

Optical properties of CdSe<Subscript>x</Subscript>Te<Subscript>1−x</Subscript> epitaxial films studied by spectroscopic ellipsometry

We have determined the dielectric constants for a series of CdSe_xTe_1−x thin films grown on Si substrates using a rotating-analyzer spectroscopic ellipsometer. Initially, the alloy concentration and the sample quality were determined using x-ray diffraction. A standard inversion technique was then used to obtain the dielectric constants from the measured ellipsometric spectra. Using these calculated absorption spectra, we were able to estimate the fundamental bandgap for these CdSe_xTe_1−x alloys. In addition, we also determined the dispersion of the indices of refraction as well as the critical points related to the higher-order electronic transitions for this alloy.     

The properties of CuInSe2-MnSe crystals

The composition and the impurity back-ground levels of (CuInSe₂)_1-x (MnSe)_2x alloy crystals are characterized by ion microprobe analyses. Room temperature photoreflectance (PR) and photoconductivity (PC) measurements in the temperature range 10 K ⪯ T ⪯ 300 K reveal changes in the point defect chemistry and a shift of the band gap with increasingx towards higher energies. Also, a deep luminescence feature at 0.89 eV is observed in Mn doped crystals, in addition to the contributions at 0.90 and 0.94 eV that appear in both doped and nominally undoped CuInSe₂. X-ray diffraction studies show that the chalcopyrite structure is retained to at leastx = 0.25.     

硅基光波导材料的研究

光波导是集成光路及其元器件中最基本的构成单元。本文介绍了各种不同类型的光波导材料的特性。硅材料作为目前研究得最透彻的半导体材料,它在光电子领域的应用也是令人关注的。硅基光波导材料种类繁多,主要包括聚合物、外延硅/重掺杂硅、SiO₂,SOI和SiGe/Si等。硅基光波导材料是实现硅基光波导器件的基础,本文阐明了它们各自的特点和应用前景。其中聚合物、SiO₂和SOI波导是目前研究的热点。     

Optical and electrochromic properties of annealed lithium-molybdenum-bronze thin films

Optical band gaps, Urbach inverse slopes, and coloration bands of various samples of annealed, microcrystalline Li_xMoO₃-bronze thin films in the concentration range 0<x<0.6 were determined over the photon energy range from 0.4 eV to 4.2 eV. On investigation, it is learned that the measured, optical band gaps do not shift rigidly over the annealing temperature range 293≤T≤423 K and, therefore, do not reveal the Burstein-Moss effect or reflect any stable, crystallographic phase transformation during any investigated annealing cycle. A model relating the temperature-dependent optical gap to the real part of the refractive index has also been developed, and this model fits very well to the annealed data within a maximum error of about 20%. Next, using an oscillator model, a phonon energy of ∼0.08 eV was obtained, which is very close to the characteristic phonon energy of the material, MoO₃. Using this model, it becomes more certain that the contributions to the Urbach absorption edge for the annealed-molybdenum bronzes are coming from the structural and compositional disorder. In another finding, it was found that the absorption-peak energy for the annealed data was about 1.5–1.6 eV, which is still broad and asymmetrical, and therefore, it is almost of the Mo⁶⁺ (or Mo⁴⁺)-Mo⁵⁺ intervalence or polaronic type. Using the polaron model, the half-bandwidth of the coloration bands of investigated, annealed Li_xMoO₃-thin films was found to be almost constant, which is consistent with the nonrigid band behavior.     

Ce和Ni共掺杂BiFeO3薄膜的光学和铁磁性能

利用溶胶-凝胶工艺在石英衬底上制备了镍铈共掺杂铁酸铋Bi_(0.9)Ce_(0.1)Fe_(1-x)Ni_xO_3(xBCFNO,x=0,0.03,0.05,0.07)薄膜.X-射线衍射(XRD)测试表明所有样品的晶体结构都为四方钙钛矿铁酸铋BiFeO_3结构.由于Ce和Ni共掺杂,XRD显示,峰位置发生偏移.主峰(012/110)峰值在Ni含量x=0.05时峰值最大.扫描电子显微镜(SEM)测试也显示x=0.05时晶粒最大,结晶度最好.光学透射测试显示xBCFNO薄膜x=0.03时的光学禁带宽度最小,为2.14 eV.铁磁测试结果表明镍铈共掺杂可以进一步提高铁酸铋的室温铁磁性.     

LiNbO3光波导F-P腔滤波器的分析设计

采用转移矩阵法推导出内置LiNbO3光波导的FP腔滤波器的功率传输系数,运用计算机进行模拟计算,分析了光波导的传输损耗和腔薄膜反射率对滤波器透射光谱的强度、带宽和精细度的影响.结果表明,传输损耗越大,透射光谱的强度变小,带宽越大;反射率越大,透射光谱的强度变小,但带宽变小,精细度增大.考虑了滤波器的透射光谱强度和精细度等因素,提出一个合理的腔薄膜反射率,优化了滤波器的设计参数.     

铋含量的变化对BixFeO3薄膜微结构和光学性质的影响

通过溶胶-凝胶技术在Si衬底上制备了x从0.80增大到1.20的Bi x FeO3薄膜样品.分析了Bi元素含量的改变对BFO薄膜微结构和光学性质的影响,表明在Bi缺失和Bi过量的Bi x FeO3薄膜样品中均出现了Bi2Fe4O9杂相和铁氧化物杂相,导致Bi x FeO3薄膜晶格的菱形扭曲结构发生变化.测试得到了薄膜的拉曼散射谱和椭圆偏振光谱,拉曼散射谱反映了Bi x FeO3薄膜样品中的振动模式明显受到x取值的影响.根据椭偏数据拟合得到的结果表明折射率在波长600 nm以下范围内随着x的减小而减小.而样品的禁带宽度从2.65 eV到2.76 eV,在x为1.05和1.10时得到最大值.     

Cu2ZnSnS4四种晶型的电子结构、光学性质和力学性质

本文采用密度泛函理论详细计算了Cu₂ZnSnS₄四种晶型的晶体结构、电子结构、光学性质和力学性质。结果表明它们之间在光学性质和力学性质方面没有非常明显的差异,计算结果与文献报道的实验数据基本一致。根据计算结果,Cu2ZnSnS4的基本带隙是由孤立导带的带宽来决定。Cu₂ZnSnS₄的载流子有效质量非常小,尤其是闪锌矿衍生的Cu₂ZnSnS₄在导带底具有极小的电子有效质量。根据所计算的力学常数矩阵可知,四种晶型的Cu₂ZnSnS₄; 均符合Born稳定性条件,而且较高的B/G比例表明Cu2ZnSnS4的四种晶型都具有突出可塑性。     

掺氮氧化铪的光学特性研究

掺氮氧化铪是半导体工业非常重要的材料。在本论文中,我们利用Hf[N(C₂H₅)(CH₃)]₄ 和 H₂O₂作为原子层淀积的前驱体,制备了二氧化铪材料。然后,我们使用快速热退火的办法,在不同温度下,对二氧化铪进行了氮掺杂工艺。我们对掺氮二氧化铪的组分,跟硅界面的稳定性以及薄膜材料的光学特性随退火温度的变化进行了细致的研究。研究发现,随着退火温度的提高,二氧化铪薄膜材料的氮组分从1.41% 上升至 7.45%,相应的,薄膜材料的禁带宽度从5.82 eV 降低为 4.94 eV。     

Tc-P共掺杂单层MoS2光电特性的第一性原理计算

采用第一性原理的赝势平面波方法,对比研究了未掺杂和掺杂过渡金属Tc、非金属P及Tc-P共掺杂的单层MoS2的电子结构和光学性质.计算结果表明:掺杂改变了费米面附近的电子结构,使得导带向低能方向偏移,并且带隙由K点转化为Γ点,形成Γ点的直接带隙半导体.掺杂P使带隙值变小,形成p型半导体;掺杂Tc使带隙变宽,形成n型半导体;Tc-P共掺杂,由于p型和n型半导体相互调制,使得单层MoS2转变为性能更优的本征半导体;掺杂使光跃迁强度减小,且向低能方向偏移.     

Optical and electrical properties of CdGeAs2

Large-grained ingots of CdGeAs₂ have been grown from near-stoichiometric melts. Resistivity and Hall coefficient (R_H) measurements were made on a large number of samples at 77 and 300 K and in some cases up to 450 K. Good fits to the log R_H vs 1/T plots are obtained by using a model that assumes three kinds of electronic levels within the energy gap: donors, shallow acceptors, and acceptors with an ionization energy of 0. 30 eV. The deep acceptors are probably native defects, since their concentration varies by nearly four orders of magnitude from ingot to ingot with little change in impurity concentration. Between the intrinsic absorption edge at about 2. 5 Μm and the two-phonon absorption band at 18 Μm, the optical absorption increases with increasing deep acceptor concentration. By using oriented single-crystal samples ∼ 1 cm on a side, conversion efficiencies as high as 27% have been achieved for second-harmonic generation with single-mode pulses from a CO₂ TEA laser.     

光波导用MgO:LiNbO3晶体光学均匀性的测定

介绍了用非临界位相匹配温度法,测量了光波导用MgO:LiNbO3晶体光学均匀性的原理、公式和实际测量的结果.