三维管状量子阱红外探测器制备与光电特性研究

发布时间：2018-05-19 01:28

本文选题：量子阱红外探测器 + 卷曲型微管　；参考：《中国科学院上海技术物理研究所》2017年博士论文

【摘要】：红外探测是现代探测技术的一个重要发展方向,它极大地拓展了人类认知自然和宇宙的视野。而红外探测器作为红外探测的核心技术之一,已发展了近两百年。在20世纪80年代,以GaAs/AlGaAs为代表的量子阱结构红外探测器开始出现并蓬勃发展,随后在国防、航空航天、天文探测和民用等领域展现出巨大且广泛的前景。量子阱红外探测器基于阱内子带跃迁原理来实现红外探测,其表现出材料生长和器件制备工艺成熟、大面积均匀性好、成品率高、响应速度快等优点,但同时也具有器件量子效率小、工作温度低、不能吸收垂直入射光(n型)等缺点。因此,如何提高器件性能指标成为量子阱红外探测器的重点研究方向之一。到目前为止,采用电子态调控手段,如优化电子输运特性和调整器件工作模式,已达到极限;但是,利用光场调控方法,如通过光耦合结构来增强量子阱光吸收进而提高器件性能,却在不断发展中。在本论文中,基于三维螺旋微管的光捕获特性,一种三维管状结构量子阱红外探测器被提出并进行了大量研究,包括:1.设计了三维管状量子阱红外探测器的材料、结构和工艺流程并进行了器件制备。具体来说,利用数值模拟方法分析管状结构的电磁耦合情况,并优化器件的结构和尺寸;依据结构特征确定材料相应功能层及各层的厚度,并使用能带计算软件设计量子阱的结构;结合材料和器件结构来定制工艺流程,并设计和制备对应的掩膜板;进行大量的实际工艺操作,完善各个流程步骤最终制备出管状器件。2.进行了三维管状量子阱红外探测器的光耦合和响应特性研究。实验制备出响应峰位于6.5μm的管状器件,在60 K工作温度和0.65 V偏压下,测得其峰值光电流响应率为381 mA/W,对应的量子效率为7.2%。通过与45o斜入射QWIP器件对比,发现了管状结构具有提高器件响应率和量子效率的能力。在详细分析微管的二维电场分布情况后,提出了其中空结构能够将一部分入射光限制在其内发生多次内反射从而增强量子阱光吸收的解释。测试管状器件在外界不同角度入射光下的黑体响应后,发现其展现出宽角度(-70o,70o)光耦合特性。此外,微管圈数对器件性能的影响也被研究。3.分析了薄膜卷曲时应力态变化对管状量子阱红外探测器的子带跃迁影响。在测试平面和管状器件的光电流响应谱后,发现应变量子阱薄膜的应力释放会导致其响应峰发生微小红移。理论分析表明,当平面应变薄膜卷成微管,管壁内部应力态的变化导致了量子阱的导带边能级偏移,进而影响到阱内电子束缚态能级和波函数,并最终造成子带跃迁产生的电流谱峰位移动。同时,不同偏压下器件的光电流响应谱也被测试,表明外加电场会导致其峰位发生蓝移,这是由对称量子阱的子带跃迁量子限制斯塔克效应造成的,且理论计算值与实验结果相符合。为了进一步改善器件性能,三维管状谐振腔量子阱红外探测器被设计出。它利用微管谐振腔的谐振效应在管壁内形成光学共振模,其强烈的光场强度能显著提高量子阱光吸收。模拟结果表明,当微管共振波长处于量子阱吸收谱范围内时,器件的响应谱上将叠加一系列尖峰,且该尖峰具有高Q值。
[Abstract]:Infrared detection is an important development direction of modern detection technology. It greatly expands the human cognition of nature and the vision of the universe. As one of the core technologies of infrared detection, infrared detector has been developed for nearly two hundred years. In 1980s, the infrared detector of quantum well structure, represented by GaAs/AlGaAs, began to appear and flourished. Development has shown great and extensive prospects in the fields of national defense, aerospace, astronomical detection and civil. The quantum well infrared detector is based on the principle of the inner subband transition of the well to realize infrared detection. It shows that the material growth and device preparation technology are mature, large area uniformity, high yield and fast response speed, but at the same time It also has the disadvantages of small quantum efficiency, low working temperature and can not absorb the vertical incident light (n type). Therefore, how to improve the performance index of the device has become one of the key research directions of the quantum well infrared detector. So far, the use of electronic state control means, such as optimizing the transmission characteristics of the electric subunit and adjusting the working mode of the device, has reached the limit. However, using optical field control methods, such as enhancing quantum well absorption by optical coupling structure and improving the performance of devices, it is developing. In this paper, based on the optical capture characteristics of three-dimensional spiral microtubules, a three-dimensional tubular structure quantum well infrared detector has been proposed and carried out a lot of research, including: 1. a three-dimensional tube is designed. The material, structure and process flow of a quantum well infrared detector are made and the device is prepared. In particular, the electromagnetic coupling of the tubular structure is analyzed by the numerical simulation method and the structure and size of the device are optimized. The thickness of the corresponding functional layer and each layer of the material is determined according to the structural characteristics, and the quantum of the energy band calculation software is used to design the quantum. The structure of the well is combined with the material and device structure to customize the process flow, and the corresponding mask plate is designed and prepared. A large number of actual process operations are carried out, and the tubular device.2. is finally prepared by various process steps to study the optical coupling and response characteristics of the three-dimensional tubular quantum well infrared detector. The experimental response peak is located at 6.5. Under the 60 K working temperature and 0.65 V bias, the peak photocurrent response rate is 381 mA/W, and the corresponding quantum efficiency is 7.2%. by comparing with the 45o oblique incidence QWIP device. It is found that the tubular structure has the ability to improve the response rate and the quantum efficiency of the device. After detailed analysis of the two-dimensional electric field distribution of microtubule, it is proposed. The space structure can explain the optical absorption of the quantum well by restricting a part of the incident light within it to enhance the optical absorption of the quantum well. Test tube devices show the wide angle (-70o, 70O) optical coupling characteristics after the blackbody response under different angles of incident light. Moreover, the influence of the number of microtubules on the performance of the device is also studied. .3. analyses the influence of the stress state on the subband transition of the tubular quantum well infrared detector when the film is curled. After the test plane and the photoelectron response spectrum of the tube, it is found that the stress release of the strain well film will lead to the slight redshift of the response peak. The change of the stress state of the part leads to the shift of the band side energy level in the quantum well, and then affects the energy level and wave function of the electron bound state in the well, and eventually causes the peak position of the current spectrum produced by the subband transition. At the same time, the photoelectric response spectrum of the devices under different bias voltage is also tested, indicating that the applied electric field will lead to the blue shift of its peak position. In order to further improve the performance of the device, a three-dimensional tubular resonant cavity quantum well infrared detector is designed. It uses the resonance effect of the microtube resonator to form the optical resonance mode in the tube wall and its strong light field intensity. The simulation results show that when the resonant wavelength of the microtubule is within the spectrum of quantum well absorption spectrum, the response spectrum of the device will be superimposed on a series of peaks, and the peak has a high Q value.
【学位授予单位】：中国科学院上海技术物理研究所
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN215

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