Study on thermal effects of InSb infrared focal plane arrays irradiated by pulsed laser

To learn thermal effects of InSb infrared focal plane arrays (IRFPAs) detector irradiated by pulsed laser, basing on ANSYS software, and considering temperature dependent thermal parameters of InSb, a three dimensional temperature field analysis model of InSb IRFPAs detector by 1064 nm Gauss laser irradiation is built. The characteristics of temperature rise and temperature distribution in InSb IRFPAs detector are studied. The results show that the maximum temperature always occurs in InSb chip, locating at the top layer of InSb IRFPAs detector, the temperature rises in each layer are different, and the temperature distribution in InSb IRFPAs detector is quite different from that in single-layer material. The temperature distribution of InSb chip in InSb IRFPAs reduces from center to outside, while it shows not a smooth decrease, but a concentric-ringed ripple decrease with non-consecutive high temperature extremum regions. The temperature distribution patterns in underfill, Si readout integrated circuits are similar to that in InSb chip, but the discontinuous high temperature areas in InSb chip, underfill locate at the regions between indium bumps, and the discontinuous high temperature areas in Si readout integrated circuits locate at the contact area with indium bumps. This different temperature distribution phenomenon in each material is mainly due to its multi-layer architecture and quite different thermal properties of the middle layer, which is an interlacing layout of underfill and indium bumps. Besides, the influences of indium bump structure size on the temperature rise are also discussed. All these results qualitatively reflect the disciplines of temperature rise in InSb IRFPAs detector, providing a theory support for thermal analysis of detectors irradiated by laser.     

缓冲层对InSb/GaAs薄膜质量的影响

InSb是制作3~5μm红外探测器的重要材料。在GaAs衬底上外延生长InSb,存在的主要问题在于两种材料间14.6%的晶格失配度,会引入较大的表面粗糙度以及位错密度,使外延材料的结构和电学性能均会受到不同程度的影响。通过系列实验,研究了在生长过程中缓冲层对薄膜质量的影响。利用高能电子衍射仪(RHHEED)得到了合适的生长速率和Ⅴ/Ⅲ比,研究了异质外延InSb薄膜生长中低温InSb缓冲层对材料生长质量以及不同外延厚度对材料电学性质的影响。采用原子力显微镜(AFM)、透射电子显微镜(TEM)、X射线双晶衍射(DCXRD)等方法研究了InSb/GaAs薄膜的表面形貌、界面特性以及结晶质量。通过生长合适厚度的缓冲层,获得了室温下DCXRD半高峰宽为172″,77 K下迁移率为64300 cm²·V^-1·s^-1的InSb外延层。     

大气遥感远紫外光谱仪绝对光谱辐照度响应度定标方法研究

主要针对可应用于空间高层大气遥感的远紫外光谱仪的光谱辐照度响应度定标方法进行研究。针对远紫外波段光谱测试标准装置少,实验系统所需真空度高,实验稳定性难以维持,传统漫反射板和积分球辐亮度定标方法在远紫外波段局限性大、难以利用等特点,研究了适用于远紫外光谱仪器的光谱辐照度绝对辐射定标方法,搭建了相应的真空实验系统,以一台远紫外光谱仪原理样机为对象对研究方法进行了实验验证。实验系统以标准氘灯、真空紫外单色仪和准直系统组成照射系统,将出射准直光辐照度用标准探测器进行标定,三者共同组成了标准光谱辐照度光源;利用该光源照射原理样机并读出相应信号,最终获得光谱辐照度响应度,从而实现了利用标准探测器进行照度传递的远紫外光谱仪器绝对光谱辐射定标,有效的进行了仪器定标。该方法定标不确定度约为7.7%,对远紫外波段空间高层大气遥感光谱仪的地面辐射定标研究具有重要意义。     

An InSb integrated photo-MOSFET fabricated by photo-enhanced chemical vapour deposition

A new output-controllable InSb infrared (i.r.) detector is proposed. The detector is fabricated by monolithically integrating an InSb p-n junction with an InSb p-channel enhancement mode metal oxide semiconductor field effect transistor (MOSFET). During operation, a photocurrent generated near the source junction is controllably switched to the drain terminal by a gate of the integrated MOSFET. The observed internal quantum efficiency in the on state is as high as 85%. Photocurrent on-off ratios are between 260 and 730, improving with increasing channel length. For longchannel devices, the photocurrent in the off state is limited by undesired leakage paths. The new structure can be used as an output-controllable i.r. detector.     

氙灯光源太阳模拟器辐照衰减器设计方法

针对应用于太阳模拟器辐照衰减器设计上的不足,提出一种新的衰减器设计方法,旨在提高其辐照均匀性.基于光学扩展量计算衰减器上的网孔面积,对会聚光路的辐射通量进行调制;利用聚光镜环带法,理论上分析衰减器上的辐射分布;利用网孔非均匀分布的结构对会聚光路的辐射分布进行调制,给出具体设计参数;对比分析了网孔均匀分布和非均匀分布对辐...     

消除强背景辐射干扰的光电探测新方法

 以InSb探测器(PV型)为例, 通过建立载流子输运的动力学模型得到光生电动势与入射光功率密度的函数关系, 提出了一种消除强背景辐射对光电探测的影响的新方法, 并且通过实验证实了这种方法的有效性及其理论模型的合理性。与传统的调零法相比, 该方法精度较高且能适用于更高强度的背景辐射 。     

消除强背景辐射干扰的光电探测新方法

以InSb探测器(PV型)为例, 通过建立载流子输运的动力学模型得到光生电动势与入射光功率密度的函数关系, 提出了一种消除强背景辐射对光电探测的影响的新方法, 并且通过实验证实了这种方法的有效性及其理论模型的合理性。与传统的调零法相比, 该方法精度较高且能适用于更高强度的背景辐射 。     

Influences of electrode material and design on the reliability of IRFPAs detector under thermal shock

Under thermal shock, high fracture probability in indium antimonide (InSb) infrared focal plane arrays (IRFPAs) limits its applicability. Typical fracture photographs under thermal shock shows that the cracks originating from the area above public electrode are dominant. In order to learn the influences of electrode material parameter and design on the reliability in InSb IRFPAs detector, the proposed improved equivalent modeling method is employed to build three dimensional InSb IRFPAs structure analysis model. Simulated results show that different electrode materials greatly influence the maximal thermal stress appearing in InSb chip and public electrode, and among the electrode material parameters, the coefficient of thermal expansion is the main affecting factor on thermal stress. With the increasing electrode thickness, the maximum thermal stresses in InSb chip and public electrode both decrease, which means the smaller electrode thickness leads to larger thermal stress in InSb chip and electrode. Besides, it is also found that adjusting the electrode layout to avoid the overlap between indium bumps and the embedded part of electrode can effectively reduce the stress concentration in the area of InSb chip above public electrode. All these are beneficial to optimize the structure of InSb IRFPAs and reduce the fracture probability.     

基于可调谐激光的光谱辐射照度响应度定标

探测器的光谱辐射照(亮)度响应度是辐射定标中最重要的参数之一.传统的光谱辐射定标采用宽谱段光源和单色仪装置测量,新建的激光辐射测量装置采用激光和探测器测量,可以大大降低测量的不确定度.该装置首先将可调谐激光耦合进入积分球生成均匀的朗伯体单色光源,然后采用低温辐射计量传的标准陷阱探测器和面积已知的光阑,进行400～900...     

Observation of Lamb dips by infrared fluorescence detection in D2CO

Fluorescence detected Lamb dips have been observed in D₂CO. The D₂CO was placed inside a CO₂ waveguide laser cavity and fluorescence detection was performed with a InSb detector. Possible explanations for this observation are discussed.     

Two kinds of “blueward shift” in the NEP spectral curves of InSb detectors

It is well-known that as the operating temperature of an InSb detector with a given sensitive area's reduced, the shape of its NEP spectral curve remains the same but shifts towards shorter wavelengths. This is called the “blueward shift”. We present here another kind of blueward shift in the InSb NEP spectral curves. It can be seen when the temperature of the detector remains constant and the equivalent zero-bias resistance of the detector increases. It is suggested in this paper that the two kinds of blueward shift can be interpreted by different physics mechanisms.     

Anisotropic growth of indium antimonide nanostructures

InSb nanostructures have been synthesized by the use of gas aggregation process. Nanoparticles with different shapes are obtained by controlling the growth and deposition temperature of the InSb nanoclusters. Triangular nanocrystals are commonly observed when the clusters are extracted from the condensation chamber of the source and deposited on the room temperature substrate at high vacuum. When the deposition is performed inside the condensation chamber at high temperature near the melting point of bulk InSb, nanoparticles formed on the substrate surface show several kinds of 3-dimensional morphologies, such as triangular or rectangular prisms, as well as hexagonal tablets. Keeping the same conditions for the cluster source operation and deposition, after long time growth, nanorods with hexagonal and quadrangular cross sections are formed through vapor-liquid-solid (VLS) process. The origin of the difference on the morphologies and shapes of the nanostructures is attributed to the anisotropic growth of InSb, which is temperature dependent.     

基于相关光子多模式相关性的InSb模拟探测器定标方法

利用基于参量下转换产生的相关光子可以实现“无溯源”的绝对定标. 将该方法推广应用于模拟探测器定标的过程中, 获取两路模拟光电流信号的有效相关信息是主要难点. 在相关光子的多模式相关性理论模型的基础上, 提出了一种新的光电流处理方案. 通过将某一时刻采集到的光电流所包含的电荷量转换为等效光子计数, 采用双光路平衡探测和双通道数据波动校正的技术思路, 开展了红外模拟探测器量子效率定标验证实验研究. 利用532 nm单波长激光器为抽运源、PPLN晶体为非线性晶体, 在25 ℃工作温度下获取了631和3390 nm的相关光子对, 定标了InSb红外模拟探测器在3390 nm处的绝对功率响应度. 结果表明, 对InSb模拟探测器的合成不确定度为7.785%. 根据量子效率与绝对功率响应度之间的函数关系, 定标结果与国内计量单位的校准结果的相对偏差为3.6%. 利用多模式相关性在模拟信号下实现红外模拟探测器的绝对功率响应度定标在国际上暂无此方面的报道, 该方法验证了应用多模式相关性理论开展模拟探测器定标方法的可行性, 对于探索基于相关光子的定标技术和拓宽辐射定标应用领域具有重要意义.     

Performance evaluation of a new reading technique of LR115 cellulose nitrate track detectors

LR115 cellulose nitrate SSNTD are routinely used for Radon detection. A reading technique with high resolution optical microscope coupled with a scanning system has been recently proposed.In this technique, the efficiency correction that was formerly performed on the residual thickness of the detector is performed on the track area distribution. So all the information that is needed for the measurement is obtained directly during the scanning. This leads to a much simpler and faster reading procedure, when compared to the classical technique that required both spark counting and micrometer residual thickness measure.A complete characterization and performance evaluation of the detector response is discussed, including a measuring range evaluation, a combined uncertainty theoretical calculation and a blind test validation at HPA.     

AAA级太阳模拟器的设计与研制

完成了一种光谱匹配、辐照不均匀度和辐照不稳定度均能达到A级标准的AAA级太阳模拟器的设计与研制。介绍了太阳模拟器的光源选择和滤光片的设计,给出了太阳模拟器的光机结构,测量了太阳模拟器的各项技术指标。结果表明,太阳模拟器的光谱匹配在波长400～1 100 nm处满足ASTM E927-10中AM1.5G A级要求。在有效辐照面55 mm×55 mm内,其平均辐照度达到1 000 W/m2,辐照不均匀度达到1.35%,辐照不稳定度达到1.27%。测量数据显示设计的太阳模拟器满足ASTM E927-10的AAA级标准。     

红外探测系统的激光辐照热效应仿真分析

为研究红外探测系统受激光辐照后的热效应与二次热辐射对探测器成像的影响,使用Ansys软件对红外探测器进行热辐射仿真和有限元结构仿真;采用黑体辐射定律和DO辐射计算模型模拟计算探测器内光学系统在不同激光辐照度下的温度随时间变化情况以及探测器内部温升对靶面成像的二次热辐射干扰情况;采用热弹性力学模型仿真计算探测器内部的热应力和热变形情况。结果表明:探测器受到1.06μm激光照射,矫正镜激光辐照度在50 W/cm²时,靶面受到二次热辐照度在0.6 s时达到100μW/cm²的量级,使红外探测器达到饱和;探测器受激光辐照后系统最高温度出现在矫正镜中心处,拟合得到系统最高温度与受照时间函数关系,可预测探测器升温结构破坏;最大热变形出现在矫正镜背面中心处,由外向内形成不等附加光程差,干扰探测器的成像效果;最大热应力出现在矫正镜前面中心处,得到最大热应力与激光辐照度间的线性关系曲线,为矫正镜热应力破坏提供预测参数。     

采用大口径投影光学系统监测远场散斑特征参数

大口径投影光学系统采用低成本、大口径菲涅耳透镜制作,可将远场散斑强度分布投影到CCD成像探测器上。通过CCD图像处理,能够对给定孔径上的接收功率、闪烁指数进行量化评估;在接收孔径足够大、保障散斑不会因为光束漂移效应而脱离菲涅耳透镜的条件下,该系统还可以对光束漂移和特征半径进行量化评估。同时讨论了CCD像元响应非均匀性误差及其影响、CCD辐照响应函数和图像几何投影系数的定标方法。实验表明,系统能够对激光大气传输过程中的远场散斑特征参数进行监测。特别对自由空间激光通信系统而言,可以为大气衰减和多种大气湍流效应综合作用下的中值电平慢衰落研究和检测阈值优化设计提供实验数据支撑。     

采用大口径投影光学系统监测远场散斑特征参数

大口径投影光学系统采用低成本、大口径菲涅耳透镜制作,可将远场散斑强度分布投影到CCD成像探测器上。通过CCD图像处理,能够对给定孔径上的接收功率、闪烁指数进行量化评估;在接收孔径足够大、保障散斑不会因为光束漂移效应而脱离菲涅耳透镜的条件下,该系统还可以对光束漂移和特征半径进行量化评估。同时讨论了CCD像元响应非均匀性误差及其影响、CCD辐照响应函数和图像几何投影系数的定标方法。实验表明,系统能够对激光大气传输过程中的远场散斑特征参数进行监测。特别对自由空间激光通信系统而言,可以为大气衰减和多种大气湍流效应综合作用下的中值电平慢衰落研究和检测阈值优化设计提供实验数据支撑。     

溯源于低温绝对辐射计的太阳光谱辐照度仪定标方法研究

为了提高太阳直射光谱辐照度的观测精度,对使用棱镜分光的太阳光谱辐照度仪,在可见-近红外波段开展了基于标准探测器的辐射定标方法研究。建立了可调谐激光器-积分球的辐照度定标装置,以溯源于低温绝对辐射计的标准辐照度探测器作为传递基准,通过替代法得到照度仪在可见-近红外10个波段的绝对光谱辐照度响应度,分析得到的合成定标不确定度优于0.95%。与溯源于中国计量院金点黑体的标准灯定标法进行了比对实验,两者的偏差在4.67%的范围内,证明了此辐射标准传递方法的合理性。     

Photoconductors under transverse sweep-out conditions

In semiconductors with induced anisotropy of conductivity the influence of transverse carrier drift on the main photodetector parameters is investigated. The effect is connected to the change in bulk and surface contributions to the total recombination flow. The calculated and experimental dependences of sensitivity, response time, spectral sensitivity and noise on transverse drift rate, bulk lifetime and surface recombination velocities are obtained. It is shown that the transverse carrier sweep-out makes it possible to stabilize detector parameters at certain values. Experiments are performed on InSb and CdHgTe samples placed in crossed electric and magnetic fields.