用于远红外探测的Si:P阻挡杂质带红外探测器研制

提出了全外延技术方案制备阻挡杂质带薄膜,避免了离子注入制备背电极层影响外延薄膜质量的技术难点.基于硅器件工艺设计制作了Si:P阻挡杂质带红外探测器.测量了器件的光电流响应谱和暗电流特性曲线,指认了叠加在光电流响应谱上的尖锐杂质峰对应阻挡层中磷原子的杂质跃迁.研究了器件在低温下小偏压范围内的暗电流起源.通过对计算结果分析,排除了该区域暗电流起源于热激发电导和跳跃式电导的可能,指出暗电流来自器件对冷屏的光电响应.器件工作温度5 K,工作偏压1.6 V时,响应波段覆盖2.5~40μm,峰值波长28.8μm,峰值响应率20.1 A/W,峰值探测率3.7×1013cm·Hz1/2/W(背景光子通量低于1013ph/cm2·s).     

可用于多波段融合的超结构/阻挡杂质带复合结构探测器（特邀）

太赫兹辐射是指频率在30 μm~1 mm范围内的电磁波,具有穿透性强、安全性高、特征性强及定向性好等特点,因此,太赫兹技术在天文观测、安全监控、物质鉴定及生物医学等领域具有广阔的应用前景。阻挡杂质带探测器具有灵敏度高、阵列规模大、探测谱段宽等核心优势,是太赫兹辐射探测的优良选择。阻挡杂质带探测器目前主要采用三种材料体系,分别为Si、Ge、GaAs。基于这三种材料体系的阻挡杂质带探测器可实现在3~500 μm的超宽波段探测。超结构是由亚波长结构单元构成人工复合结构,在光电探测器上引入超结构,利用等离激元共振、偶极共振调控特性,可以将电磁场能量强烈的局域在金属/探测器界面位置。因此,超结构与阻挡杂质带结合,可有效调控探测峰位、缩小探测峰半高宽、强化光谱分辨能力,并有望大规模应用于3~500 μm的多波段融合探测。同时,超结构与阻挡杂质带探测器结合,可进一步提高器件响应率,减小器件尺寸,降低工艺难度。文中简要叙述了阻挡杂质带探测器的工作机理,介绍了国内外阻挡杂质带探测器的研究历史及研究现状。最后,在探测器波段调控、光谱分辨、增强吸收等角度详细介绍了Si、Ge、GaAs基超结构/阻挡杂质带复合结构探测器的研究现状,并结合目前该技术发展瓶颈问题,在高纯材料生长、光场局域效应机理研究等方面提出了下一步的研究展望。     

硅基阻挡杂质带太赫兹探测器及其成像研究

太赫兹探测及成像技术是推动太赫兹科学技术发展的基础和关键.为了实现高灵敏太赫兹探测及成像,设计了一种台面型硅基阻挡杂质带太赫兹探测器,详细介绍了其结构及探测机理,描述了其制备工艺流程,并搭建了黑体响应测试系统.结果表明,4.2K温度条件下,3.8V工作偏压时,探测器峰值响应率可达55A/W,响应频段覆盖6.7～60THz.此外,搭建了一套两维扫描成像系统,实现了高分辨率被动成像.实验结果表明,成像系统空间分辨率可达400μm、温度分辨率约为7.5mK.     

基于CMOS工艺的双层非制冷热敏电阻型红外探测器

采用0.5μm标准CMOS工艺和微机械加工工艺,设计并制作了低成本双层非制冷热敏电阻型红外探测器。探测器采用隐藏桥腿式微桥结构,使用表面牺牲层技术实现,其中包括Al、W和Si3种牺牲层材料。CMOS工艺加工完成后,双层微桥结构的微机械加工过程只需进行湿法腐蚀即可,成本较低。对双层红外探测器的热性能和光电特性进行测试,其热导为1.96×10-5 W/K,热容为2.23×10-8 J/K,热时间常数为1.14ms。当红外辐射调制频率为10Hz时,双层红外探测器的电压响应率为2.54×104 V/W,探测率为1.6×108 cm·Hz1/2/W。     

热电制冷HgCdTe中波红外探测器的研制

利用碲镉汞(HgCdTe)体晶材料,采用HgCdTe材料拼接技术、磨抛技术等成熟的探测器芯片制备工艺以及三级热电制冷技术,设计并研制出了热电制冷型13元HgCdTe中波红外光导探测器。在-50℃时,峰值电压响应率可达2.7×104 V/W,峰值探测率达到2.3×1010 cm·Hz1/2·W-1,响应波段在3.0~4.6mm之间,峰值响应波长为4.2mm。     

用CMOS工艺方法制作的低成本非致冷红外探测器（上）

本文介绍用标准的 n 阱 CMOS 工艺方法实现的两种低成本非致冷红外微测辐射热计探测器，并对它们的性能进行了比较，其中一种探测器基于悬置式 n 阱电阻器，它是用0.8μm 的 CMOS 工艺方法制作的，其像元尺寸为80μm×80μm,占空因数为13%；另一种探测器基于悬置的p~+激活/n 阱二极管，这是用0.35μm 的 CMOS 工艺方法制作的，其像元尺寸为 40μm×40μm，占空因数为44%,在 CMOS 制作之后，这些探测器用简单的整体微机械加工方法即可获得，无需任何复杂的平版印刷或者淀积工序，在20μA 的偏置电流和'80毫乇的真空条件下，测得的二极管型探测器的响应率(π)为4970V/W，热时间常数为35.8ms，在带宽为4kHz 时，测得的均方根噪声为0.52μV，结果其探测率(D~#)为9.7×10~8cmHz~1/2/W.与二极管型探测器相比，电阻器型 n 阱探测器在1.68V 的偏压下能达到同样的直流响应率，但其自热却10倍于二极管型探测器，在带宽为4kHz 时，这种探测器的均方根噪声为0.81μV，由此得出的探测率(D~*)为8.9×10~8cmHz~1/2/W。如果给电阻器型 n 阱探测器施加更高的偏压，其探测率还可提高，但其自热会更高，由于二极管型探测器在像元尺寸较小和所加偏压更低的情况下仍具有比较高的响应率，因此更适用于低成本大规格红外探测器列     

近表面加工技术制备的高性能Ge:B 阻挡杂质带探测器

阻挡杂质带（BIB）探测器是当前远红外天文探测领域的主流探测器。通过近表面加工技术成功制备出了高性能的Ge:B BIB探测器,响应波数范围从50 cm^-1到400 cm^-1。在3.5 K温度和30 mV工作电压下,器件在峰值响应84.9 cm^-1处的响应率达到21.46 A·W^-1,探测率达到4.34×10¹⁴cm·Hz^1/2·W^-1。研究了BIB探测器中界面势垒对响应光谱的影响。提出了一种新的激发模式—电极区内的载流子可以通过光激发的方式越过势垒。此外,还发现了一种增强BIB探测器在小波数处相对响应强度的方法。     

一种具有高填充因子吸收层和低失调低噪声读出电路的红外探测系统

使用红外探测器及读出电路,研制成功非制冷红外探测系统.探测器用二极管作为温度传感器,使其与集成电路工艺相兼容.采用了新的器件结构,使得填充因子从20%提高到80%.器件的微机械结构面积为35μm×35μm.读出电路的失调电压为3μV.探测器的输出噪声为2μV.探测器的电压响应率为7 894.7 V/W,黑体探测率D*为1.56×109cmHz1/2/W,噪声等效温差为330 mK,响应时间为27 ms.     

"风云二号"卫星用水汽/热红外双波段探测器

报导了我国第一颗静止气象卫星"风云二号"卫星多通道扫描辐射计中使用的水汽/热红外双波段6.3～7.6μm、10.5～12.5μm四元碲镉汞红外探测器性能.探测器工作温度T=100K时,热红外波段探测率D*(10.5～12.5)为3.4×1010cmHz1/2/W,波段响应率R(10.5～12.5)为3.0×104(V/W);水汽波段探测率D*(6.3～7.6)为1.1×1011cmHz1/2/W,波段响应率R(6.3～7.6)为6.1×104(V/W).探测器经过环境应力筛选,密封筛选,电应力筛选,抗太阳辐照试验,电子、质子辐照试验以及高真空、低温工作寿命试验,获得了探测器可靠性寿命数据,器件失效率小于7.5×10-6/h.     

基于超薄钽酸锂晶体材料高响应太赫兹探测器

太赫兹(Thz)探测器工作在室温条件下极大地促进了太赫兹科学与技术的应用。超薄(10μm)钽酸锂(LiTaO3)晶片被用作太赫兹探测器敏感元材料。基于钽酸锂晶片太赫兹探测器在2.52 THz激光辐射源照射下, 20Hz斩波频率时响应率可达到8.38×104V/W, 等效噪声功率NEP)可达到1.26×10-10W。这种加工超薄钽酸锂晶片的方法为制备高响应率太赫兹探测器提供了一个可行的方法。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.