太赫兹量子阱探测器研究进展

太赫兹量子阱探测器具有皮秒级的响应时间和1 GHz以上的高速调制性能,是太赫兹快速成像和高速无线通信应用领域非常有前景的探测器.文章综述了太赫兹量子阱探测器的探测原理和设计方法、器件主要性能指标和基于该探测器的应用技术研究进展.研究表明,基于太赫兹量子阱探测器的快速成像系统可以获得物体的细节信息,有望用于安全检查和无损...     

太赫兹量子阱探测器性能研究及提高

提出了一个砷化镓基(GaAs/Al_(0.04)Ga_(0.96)As)太赫兹量子阱探测器,并对其光电流谱和背景噪声限制温度进行了表征,得到峰值响应频率为6.78 THz,背景噪声限制温度为16 K.理论上,首先,考虑多体效应对器件能带结构的影响,计算得峰值响应频率为6.64 THz,考虑到制备过程中的误差(THz器件较中红外器件,铝组分低,阱宽窄),理论与实验吻合的较好,证实了多体效应在太赫兹量子阱探测器中的重要影响;然后,对器件的电流电压特性进行研究,计算得到背景噪声限制温度为17.5 K,与实验吻合.太赫兹量子阱探测器较低的工作温度,极大限制了其应用,提出了两种实现高温探测的方法:(1)引入光学汇聚天线,提高器件背景限制温度,计算结果表明当引入增强系数为10~6倍的天线时,其背景噪声限制温度达到97 K(远高于液氮温度77 K);(2)太赫兹量子阱探测器与太赫兹量子级联激光器联用,可实现信号噪声限制模式,从而实现高温探测.计算表明,当激光器功率达到0.003 mW/μm~2,器件的工作温度可达77K.     

基于肖特基二极管的太赫兹准光探测器设计方法与成像性能研究

设计了一款太赫兹准光探测器, 该探测器主要由砷化镓肖特基二极管芯片以及高阻硅透镜组成.为了减小所设计芯片的欧姆损耗, 将天线图案生长在了半绝缘砷化镓层上.在335～350GHz频率范围内, 准光探测器的实测电压响应率为1360～1650V/W, 双边带变频损耗为10.6～12.5dB.对应估算的等效噪声功率为1.65～2pW/Hz1/2.基于所设计的准光探测器进行了成像实验, 该实验分别在直接检波和外差探测两种模式间进行, 成像结果表明所设计的太赫兹准光探测器能够满足太赫兹成像方面应用.     

太赫兹波探测技术的研究进展

太赫兹波具有优越的特性,使其在物理、化学、生物医学、天文学、材料科学和环境科学等方面有重要的学术和应用价值,以及对国民经济发展、国家安全、反恐和新一代信息科学技术有重大的推动作用,作为太赫兹技术应用的关键器件之一的太赫兹探测器同样到了迅猛的发展。文章介绍了太赫兹探测技术的原理及其应用,并在此基础上分析了太赫兹探测器的最新进展、性能和发展趋势。     

太赫兹波探测器技术研究进展

对现有的几种常见太赫兹探测技术进行了总结,介绍了探测太赫兹脉冲信号的THz-TDS技术、外差探测的相干探测技术以及基于热吸收的直接探测技术。分析了等离子波探测器相对于传统电子和光子探测器的优势,并重点介绍了以石墨烯为材料的新型太赫兹探测器的研究进展。     

太赫兹波探测器的研究进展

太赫兹技术涉及电磁学、半导体物理学、光电子学、材料科学以及微加工技术等多个学科.太赫兹探测器是太赫兹技术应用的关键器件之一.太赫兹电磁波独特的特点,令太赫兹技术在物体成像、射电天文、宽带移动通信、医疗诊断、环境监测等方面具有重大的科学研究价值和广阔的应用前景.文章介绍了太赫兹探测技术的原理及其应用,并在此基础上分析了太赫兹探测器件的最新进展、性能和发展趋势.     

热电型太赫兹探测器的快速测试方法研究

针对热电型太赫兹探测器测试速度慢的缺陷,本文研究一种热电型太赫兹探测器测试数据的快速处理方法,提高热电型太赫兹探测器的测试效率.首先使用输出功率稳定的太赫兹源测试热电型太赫兹探测器的上升曲线,获得热电型太赫兹探测器的时间常数;其次研究热电型太赫兹探测器上升曲线的函数形式;然后依据热电型太赫兹探测器的时间常数和函数形式,推导热电型太赫兹探测器测试数据的快速计算公式;最后采用逐次累加取平均的方法对热电型太赫兹探测器的快速计算数据进行平滑处理.理论分析和实验结果表明:此方法不仅提高了热电型太赫兹探测器的测试效率,而且降低了测试结果的噪声,有利于太赫兹激光功率的快速测试.     

量子阱太赫兹探测材料设计与生长的研究*

子带跃迁的量子阱结构太赫兹探测器具有响应速度快等特点,有广泛的应用前景,越来越受到研究 人员的关注。以量子力学基本原理,量子阱结构材料光吸收的特性,以及光导型探测器暗电流分析为基础,进行了 量子阱厚度、势垒层Al 含量和量子阱掺杂浓度等参数的AlGaAs/ GaAs 量子阱太赫兹探测材料结构设计,按照优化 后的外延参数进行了材料生长,获得了符合设计要求的探测材料。     

采用CMOS太赫兹波探测器的成像系统

太赫兹波成像技术在生物医疗和安全检测等领域具有广阔的应用前景。针对新一代信息技术对便携式太赫兹波成像设备的需求,设计了基于CMOS太赫兹波探测器的成像系统。该系统包括一款CMOS太赫兹波探测器、片外模数转换器（ADC）、FPGA数字信号处理器、二位步进机、四个抛物面镜和太赫兹波辐射源等。CMOS太赫兹波探测器集成了片上贴片天线以及作为检波元件的NMOS晶体管,探测器由180 nm标准CMOS工艺制成。太赫兹波探测器的输出被片外模数转换器（ADC）采集并转换为数字信号,该数字信号被FPGA采集并传输到电脑上成像。所有上述元件均被装备在印刷线路板（PCB）上以减小系统体积。该系统实现了透射式太赫兹波扫描成像而无需斩波-锁相技术,并给出在860 GHz的太赫兹波照射下隐藏在信封内部金属的成像结果。     

基于拓扑绝缘体异质结的宽带太赫兹探测器

二维材料中的新量子态对凝聚态物理和现代光电器件的发展具有重要意义。然而具有宽带、室温和快速响应能力的太赫兹光电探测技术,由于缺乏暗电流和光吸收之间的最佳平衡,仍然面临着巨大的挑战。在这项研究中,作者合成了新型拓扑绝缘体材料GeBi₄Te₇,并搭建了其与Bi₂Te₃的范德华异质结,以实现高灵敏度的太赫兹光电探测器。在平面金属-材料-金属结构中实现了在室温下将低光子能量太赫兹波段直接转化为光电流。结果表明,基于Bi₂Te₃-GeBi₄Te₇的太赫兹光电探测器能够实现0.02～0.54 THz的宽谱探测,且具有很高的光响应率(在0.112、0.27、0.5 THz下分别为592 V·W^-1、203 V·W^-1、40 V·W^-1),响应时间小于6μs。值得注意的是,它被用于高频太赫兹的成像应用演示。这些结果为Bi₂Te₃     

Resonant cavity-enhanced mercury cadmium telluride detectors

The next-generation mercury cadmium telluride (HgCdTe) detectors will need to be able to spectrally resolve images to a degree far exceeding that currently available in two or even three color techniques. However, narrow, spectral pass bands will result in very low photon flux impinging on a detector. This paper investigates the use of resonant cavity-enhanced (RCE) detectors as a means of improving signal-to-noise performance of narrow spectral-width infrared (IR) detection systems.     

InP基共振隧穿二极管太赫兹振荡器的设计与实现

利用InP基共振隧穿二极管（RTD）和加载硅透镜的片上天线设计实现了超过1 THz的振荡器。采用Silvaco软件对RTD模型进行仿真研究,分析了不同发射区掺杂浓度、势垒层厚度、隔离层厚度以及势阱层厚度等对器件直流特性的影响规律。对研制的RTD器件直流特性测试显示：峰值电流密度Jp为359.2 kA/cm²,谷值电流密度Jv为135.8 kA/cm²,峰谷电流比PVCR为2.64,理论计算得到的器件最大射频输出功率和振荡频率（fmax）分别为1.71 mW和1.49 THz。利用透镜封装的形式对采用Bow-tie片上天线和RTD设计的太赫兹振荡器进行封装,测试得到振荡频率超过1 THz,输出功率为2.57μW,直流功耗为8.33 mW,是国内首次报道超过1 THz的振荡器。     

Detectivity studies of SMD-packaged ZnSSe and ZnMgS UV detectors

The 1/f noise and shot noise studies were carried out on molecular beam epitaxy (MBE)-grown ZnS_0.85Se_0.15 and Zn_0.43Mg_0.57S ultraviolet (UV) detectors packaged in surface mount lead frames. Three ZnS_0.85Se_0.15 detectors with different thicknesses of the active layer and the top electrode pad were used. The highest onset of reverse bias for the appearance of 1/f noise is ?27.5 V, and the highest dark resistances at zero bias is R₀=3.7×10¹³ Θ. The observed difference in their noise performance implies that the increase of the thicknesses of both the active layer and the top electrode pad can significantly lower the noise levels and in turn lead to higher detectivity. The best detectivity achieved is 8.75×10¹³ cm Hz^1/2 W^?1 in a ZnS_0.85Se_0.15 detector with an active layer of 5000 Å and a top electrode pad of Cr (50 Å)/Au (8000 Å). The typical detectivity achieved on Zn_0.43Mg_0.57S devices that have an active layer thickness just exceeds the critical thickness of phase transition is 1.54×10¹² cm Hz^1/2 W^?1.     

一种局域化协同增强太赫兹波电磁场的超材料

设计了一种太赫兹(THz)波段的超材料,可以实现 对垂直入射THz波的电、磁场局域化协同增强。数 值仿真表明,在线偏振的THz脉冲垂直辐照下,利用本文超材料的结构能得到强显著增强且 高度局域化的电、磁场 分布,入射THz波的电、磁场分量可以分别增强20倍;被增强的电、磁场局域化 在μm²尺度范 围内,且在空间上不重叠。基于等离激元理论分析了超材料内部的面电流分布以及超材料内 部电 荷的积累,给出了电磁场协同增强及局域化的理论解释,即超材料的特殊结构产生的 电容效应及面 电流的汇聚作用分别是导致电、磁场协同局域化增强的原因。最后,具体分析了超材料关键 的几何参数对 于场增强效果的影响。本文提出的超材料方案,有望应用于THz波段近场光学、非线性光 学及THz波与磁有序介质相互作用等领域。     

GaAs基量子阱谐振腔增强型光电探测器特性研究

通过对谐振腔增强型（RCE）光电探测器的理论分析和实验测试结果，证明对应不同光束入射角度， RCE光电探测器的模式波长按一定规律可调谐. 并给出当入射角度变化10°～60° ，模式调谐范围约为40nm，而谐振波长处的量子效率峰值及半高宽FWHM的变化与材料吸收系数紧密相关.     

SOI基蓝紫光敏感光电探测器的设计与模拟

According to Lambert’s law,a novel structure of photodetectors,namely photodetectors in siliconon-insulator,is proposed.By choosing a certain thickness value for the SOI layer,the photodetector can absorb blue/violet light effectively and affect the responsivity of the long wavelength in the visible and near-infrared region,making a blue/violet filter unnecessary.The material of the SOI layer is high-resistivity floating-zone silicon which can cause the neutral N type SOI layer to become fully depleted after doping with a P type impurity.This can improve the collection efficiency of short-wavelength photogenerated carriers.The device structure was optimized through numerical simulation,and the results show that the photodiode is a kind of high performance photodetector in the blue/violet region.     

Design and simulation of blue/violet sensitive photodetectors in silicon-on-insulator

According to Lambert's law, a novel structure of photodetectors, namely photodetectors in silicon on-insulator, is proposed. By choosing a certain thickness value for the SOI layer, the photodetector can absorb blue/violet light effectively and affect the responsivity of the long wavelength in the visible and near-infrared re gion, making a blue/violet filter unnecessary. The material of the SOI layer is high-resistivity floating-zone silicon which can cause the neutral N type SOI layer to become fully depleted after doping with a P type impurity. This can improve the collection efficiency of short-wavelength photogenerated carriers. The device structure was optimized through numerical simulation, and the results show that the photodiode is a kind of high performance photodetector in the blue/violet region.     

单光子源和单光子探测器研究进展

在众多的量子信息方案中,光学方法是独特的,因为它们允许长距离的通信且提供量子计算新的方法.在光量子信息处理过程中,单光子源和探测器是很重要的一个方面.本文回顾了测量和产生单光子的方法,且讨论了它们在量子信息处理中的应用.     

Molecular beam epitaxial growth and performance of HgCdTe-based simultaneous-mode two-color detectors

Molecular beam epitaxy was employed for the growth of HgCdTe-based n-p⁺-n device structures on (211)B oriented CdZnTe substrates. The device structures were processed as mesa isolated diodes, and operated as back-to-back diodes for the simultaneous detection of two closely spaced sub-bands in the mid-wave infrared spectrum. The devices were characterized by R₀A values in excess of 5 × 10⁵ Ω cm² at 78K, at f/2 fov and quantum efficiencies greater than 70% in each band. Infrared imagery from a focal plane array with 128 × 128 pixels was acquired simultaneously from each band at temperatures between 77 to 180K, with no observable degradation in the image quality with increase in temperature.     

Modeling of optical response in graded absorber layer detectors

Commercial and military applications for ir detectors continually push the performance envelope to achieve the highest signal-to-noise ratio at the longest possible wavelength. The highest performance is generally achieved when the detector cutoff wavelength is made as short as possible to minimize dark current while maintaining high uniform responsivity over the system optical passband. This requires an accurate prediction of the detector spectral shape near cutoff. As the incident wavelength approaches cutoff, the optical absorption coefficient decreases and internal reflections within the layer become important, causing constructive or destructive interference and consequently modulation of the detector spectral shape. The analysis is complicated since the absorber layer often includes compositional grading, particularly for very long-wavelength IR devices. This article describes an approach for analyzing the spectral response of backside-illuminated, compositionally graded detectors, and the results are compared with experimental data. The analysis shows that the spectral shape near cutoff is impacted by a weak resonance within the absorber created by a combination of a strong reflection from the detector front side and a weak reflection from the absorber-substrate backside interface. The analysis, which is an extension of the work of Rosenfeld et al., takes into account the weak resonance through computation of the optical field and generation rate by the Wetzel-Kramers-Brillioun (WKB) method. The method has been compared with experimental data for several cases using both parabolic and hyperbolic models for the absorption coefficient, and excellent agreement is achieved with the hyperbolic model.