室温长波MCT探测器研究

介绍了昆明物理所对室温长波Ｈｇ１－ｘＣｄｘＴｅ光导探测器研究的进展情况。采用ＭＣＴ体晶材料已制备出室温８～１４μｍ光导探测器，其λｃ＝１１．６μｍ，Ｄ＊＝１．１６×１０７ｃｍＨｚ１／２／Ｗ。     

长波碲镉汞探测器工作温度对输出图像的影响

为分析长波碲镉汞探测器在高低温环境下盲元增加的问题,通过试验对长波碲镉汞探测器组件进行测试,并观察输出图像。可以发现,改变环境温度后,经探测器校正的所得图像发生变化。分析原因并对其进行了试验验证。结果表明,环境温度会影响探测器的输出图像及性能,即芯片的工作温度变化会引起暗电流和波长变化。     

All-Solid-State Electro-Chemo-Mechanical Actuator Operating at Room Temperature

Dimensional change in a solid due to electrochemically driven compositional change is termed electro-chemo-mechanical (ECM) coupling. This effect causes mechanical instability in Li-ion batteries and solid oxide fuel cells. Nevertheless, it can generate considerable force and deformation, making it attractive for mechanical actuation. Here a Si-compatible ECM actuator in the form of a 2 mm diameter membrane is demonstrated. Actuation results from oxygen ion transfer between two 0.1  µ m thick Ti oxide\Ce_0.8Gd_0.2O_1.9 nanocomposite layers separated by a 1.5  µ m thick Ce_0.8Gd_0.2O_1.9 solid electrolyte. The chemical reaction responsible for stress generation is electrochemical oxidation/reduction in the composites. Under ambient conditions, application of 5 V DC produces actuator response within seconds, generating vertical displacement of several µm with calculated stress ≈ 3.5 MPa. The membrane actuator preserves its final mechanical state for more than 1 h following voltage removal. These characteristics uniquely suit ECM actuators for room temperature applications in Si-integrated microelectromechanical systems.     

HgCdTe光导芯片室温电阻率不稳定问题探讨

集中讨论 MCT 光导芯片电阻率随时间变化的问题。研究结果表明:MCT芯片中 Hg 原子的逐渐逸出导致了材料组分即 x 值随时间变化,这是芯片室温电阻率变化的主要原因;另外,在某些条件下(如加温),芯片表面可形成高浓度的 n 型载流子薄层,也将引起芯片的室温电阻率的变化。     

Light-Driven Polymer-Based All-Solid-State Lithium-Sulfur Battery Operating at Room Temperature

Poly(ethylene oxide)-based polymer all-solid-state Li S battery is a promising candidate due to its high specific energy, good processability, and low cost. However, the poor room temperature ionic conductivity limits its further development. Here an innovative photothermal battery technology is proposed to realize the normal operation at room temperature. This design places the 3D Cu substrate with Cu/Si core-shell structures between Li anode and outer encapsulation glass, so that the light can come in and generate heat efficiently by utilizing the carrier nonradiative recombination of Si nano shell, then the heat quickly transfers to the battery system through Cu core. Once simulated sunlight irradiates, the battery achieves a fast reaction kinetics and superior photothermal conversion, thus realizing a lifespan of over 20 cycles with a capacity of 1089.9 mAh g⁻¹ at 0.2 C. Even on the actual sunlight irradiation, a high discharge/charge capacity of 1065.2/1036.5 mAh g⁻¹ is also reached, indicating an excellent reversible electrochemical process. Moreover, the 3D nanostructure can accommodate the fatal volume variation of lithium and reduce the effective current density, thus suppressing the dendrite nucleation and growth. This study will open the avenue to develop a room temperature polymer all-solid-state Li S battery using photothermal technology.     

长波HgCdTe光导探测器液氮温度电阻和室温电阻比值计算

研究了长波ＨｇＣｄＴｅ光导探测器液搂温度电阻和室温电阻比值计算问题。结果表明：制成器件后，表面导导，材料电导率的变化和背景辐射都将使器件液氮温度的电阻减小，进行这三项修正后，器件电阻比值的计算值与实验值吻合。     

HgCdTe红外探测器性能分析

根据碲镉汞材料的性能、碲镉汞红外探测器物理机理和基本器件模型,对截止波长为3 m、5 m、10.5 m的碲镉汞探测器,在不同工作温度下的探测率性能进行了理论计算。计算结果表明:碲镉汞探测器在短波、中波和长波三个主要红外波段均能满足第三代红外焦平面器件对灵敏度和工作温度的要求。     

Status of HgCdTe Bicolor and Dual-Band Infrared Focal Arrays at LETI

In this paper we show the latest achievements of HgCdTe-based infrared bispectral focal plane arrays (FPAs) at LETI infrared laboratory. We present and compare the two different pixel architectures that are studied now in our laboratory, named “NPN” and “pseudo-planar”. With these two technologies, a wide range of system applications in dual-band detection can be covered. Advantages of both architectures will be pointed out. We also review performances obtained with these different architectures. The first one has been studied for several years in our laboratory, and we review results obtained on FPAs of size 256 × 256 pixels on a 25 μm pitch, in the MWIR/MWIR (3 μm/5 μm) range. Very high noise equivalent temperature difference (NETD) operability is obtained, at 99.8% for the λ_c = 3 μm band and 98.7% for the λ_c = 5 μm band. The second one has been developed more recently, to address other applications that need temporal coherence as well as spatial coherence. We show detailed performances measured on pseudo-planar type FPAs of size 256 × 256 pixels on a 30 μm pitch, in the MWIR/LWIR (5 μm/9 μm) range. The results are also very promising for these prototypes, with NETD as low as 15 mK for an integration time as short as 1 ms, and good operability. The main manufacturing issues are also presented and discussed for both pixel architectures. Challenging process steps are, firstly, molecular beam epitaxy (MBE) HgCdTe heterostructure growth, on large substrates (cadmium zinc telluride) and heterosubstrates (germanium), and, secondly, detector array fabrication on a nonplanar surface. In particular, trenches or hole etching steps, photolithography and hybridization are crucial to improve uniformity, number of defects and performances. Some results of surface, structural and electrical characterizations are shown to illustrate these issues. On the basis of these results, the short-term and long-term objectives and trends for our research and development are presented, in terms of pixel pitch reduction, wavelengths, and dual-band FPA size.     

室温工作双敏感膜HSGFET型O3传感器的研究

本文研究室温下工作,具有双敏感膜,检测ppb范围内O₃浓度的复合悬浮栅FET(Hybrid Suspended Gate Field Effect Transistor即HSGFET)型臭氧传感器.文中给出了四种固态HSGFET型臭氧传感器的实验结果,发现具有 结构的传感器对O₃有很好的响应特性;实验结果与由开尔芬(Kelvin)探针得到的结果进行了比较.     

室温CdZnTe核辐射探测器研究进展

简述了CdZnTe材料与探测器的发展、国内外的研究现状及其广泛应用,分析了存在的问题和解决方法,同时介绍了本单位CdZnTe探测器的研发情况,包括探测器的制备工艺及性能测试与分析.制备出了性能优良的阵列像素(3×3)探测器,其57Co 122 keV光谱能量分辨率为23.7%(28.9 keV FWHM),137Cs 662 kev光谱分辨率为17.9%(117.8 keV FWHM).     

离子束刻蚀光导HgCdTe探测器芯片的温度限制

利用离子对束对光导ＨｇＣｄＴｅ芯片阳极氧化膜，Ｃｒ－Ａｕ电极和ＨｇＣｄＴｅ芯片的成形进行刻蚀，要求ＨｇＣｄＴｅ芯片表面温度不能超过８０℃。     

激光辐照HgCdTe探测器的温度场数值分析

建立激光辐照下HgCdTe光电导探测器的非稳态物理模型，进行温升计算，得到温度场分布的数值解。分析瞬态温度场分布随时间变化的关系，讨论了激光辐照对探测器性能参数的影响，实践证明，本研究方法简便有效，能够对器件机理的分析提供理论依据。     

基于FPGA的星载HgCdTe探测器温控系统设计

大气主要温室气体检测仪采用HgCdTe探测器实现CO₂温室气体干涉光谱数据探测,HgCdTe探测器工作温度对探测器性能具有重要影响。针对HgCdTe探测器恒定低温下工作的需求,设计了温度采集电路与温控功率驱动电路,并以Actel公司反熔丝工艺FPGA作为主控单元, 结合PID算法,完成了星载HgCdTe探测器温控系统,实现了探测器在轨温度控制。实验及应用结果表明,控温精度优于0.5℃, 控温稳定性优于0.1℃/s,满足HgCdTe探测器在轨工作温度要求。     

Study of Morphological Defects on Dual-Band HgCdTe on CdZnTe

HgCdTe dual-band epitaxial layers on lattice-matched CdZnTe substrates often have morphological defects. These defects, unlike normal void and microvoid defects, do not contain a polycrystalline core and, therefore, do not offer a good contrast for observation using optical and electron microscopes. This paper reports a way of identifying these defects by using a Nomarski optical microscopy image overlay on focused ion beam microscopy images for preparation of thin cross-sectional foils of these defects. Transmission electron microscopy was used to study the defect cross-sections to identify the origin and evolution of the morphological defects and their effect on the epitaxial layer. This paper reports cross-sectional analysis of four morphological defects of different shape and size.     

锑化物中/中波双色红外探测器研究进展

面对第三代红外探测器对多波段探测的需求,中/中波双色同时获取两个波段的目标信息,对复杂的背景进行抑制,可以有效排除干扰源的影响,提高了探测的准确性,增强了在人工及复杂背景干扰下的目标识别能力,因此中/中波双色探测器设计和制备最近快速发展起来。锑化铟红外探测器通过分光可实现两个中波波段的探测,锑化物Ⅱ类超晶格探测器通过能带结构设计实现多波段探测。本文阐述了锑化物中/中波双色红外探测器的主要技术路线和目前研究进展,与传统InSb双色探测器相比,中/中波双色超晶格红外器件用于红外成像探测具有鲜明的特点和优势,但需要在探测器结构设计、锑化物超晶格材料生长、阵列器件制备等方面进行进一步研究,以提高探测性能,满足工程化应用需求。     

Cross-Sectional Study of Macrodefects in MBE Dual-Band HgCdTe on CdZnTe

HgCdTe dual-band mid-wave infrared/long-wave infrared focal-plane arrays on CdZnTe are a key component in advanced electrooptic sensor applications. Molecular beam epitaxy (MBE) has been used successfully for growth of dual-band layers on larger CdZnTe substrates. However, the macrodefect density, which is known to reduce the pixel operability and its run-to-run variation, is larger when compared with layers grown on Si substrate. This paper reports the macrodefect density versus size signature of a well-optimized MBE dual-band growth and a cross-sectional study of a macrodefect that represents the most prevalent class using focused ion beam, scanning transmission electron microscopy, and energy-dispersive x-ray spectroscopy. The results show that the macrodefect originates from a void, which in turn is associated with a pit on the CdZnTe substrate.     

用于室温红外探测的新型非晶硅薄膜晶体管

研究了用于室温红外探测的非晶硅薄膜晶体管。分别从理论和实验角度对非晶硅薄膜晶体管的沟道电流随着宽长比的线性变化进行了分析验证。理论分析和实验结果表明,增大晶体管的宽长比不会影响沟道电流温度系数,但可以显著改善探测器的探测率,从而为a2SiTFT红外探测器的优化设计指明了方向。     

论高工作温度碲镉汞红外探测器（上）

与用其他材料制备的红外光子探测器相比,碲镉汞红外探测器具有带隙灵活可调、量子效率较高以及R_0A接近理论值等优点。碲镉汞探测器的主要缺点是需要低温制冷,以抑制引起噪声的热生自由载流子。期望碲镉汞探测器在具有高工作温度(High Operating Temperature,HOT)的同时而又无需牺牲性能。HOT碲镉汞探测器的设计目标主要是抑制俄歇过程,从而降低探测器噪声和低温制冷需求。从相关基本概念出发,讨论了对HOT碲镉汞物理机制的理解以及近年来HOT碲镉汞技术的发展状况。     

Low-Frequency Noise Characteristics of HgCdTe Infrared Photodiodes Operating at High Temperatures

We present experimental results of 1/f noise characterization in n ⁺/p mercury-vacancy-doped photodiodes. The 1/f noise was measured as a function of temperature and diode bias voltage for different photodiode configurations. We have investigated the 1/f noise of devices with various geometries and structures, in different spectral bands, and produced using different growth processes. Contrasting 1/f noise behavior was observed in mid-wavelength infrared range (MWIR) and long-wavelength infrared range (LWIR) devices. The results indicate that the 1/f noise in MWIR photodiodes is proportional to the diode area, which implies the presence of a previously unreported noise-generating mechanism occurring in bulk material. The 1/f noise in the LWIR photodiodes was found to be independent of diode geometry, indicating the presence of a diffusion current modulation at specific points of the junction.     

退火温度下Hg在HgCdTe中的扩散机制

首先分析了Ｈｇ在ＨｇＣｄＴｅ晶格中所处的两种状态和Ｈｇ成ＨｇＣｄＴｅ外延层的扩散过程,然后提出了一种扩散模型,从理论上得到Ｈｇ在ＨｇＣｄＴｅ中的扩散深度与扩散时间的平方根成正比。对于在Ｈｇ饱和条件下退火后的ＨｇＣｄＴｅ,用逐层腐蚀法测量了Ｈｇ在其中的扩散与扩散时间的关系。实验表明其结果与理论模型较吻合。