Experimental Study of MQW RCE Photodetector

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｔｈｅｉｎｃｒｅａｓｉｎｇｄｅｍａｎｄｓｆｏｒｉｎｆｏｒｍａｔｉｏｎｔｒａｎｓｆｅｒｈａｖｅｌｅｄｔｏａｇｒｅａｔｄｅａｌｏｆｉｎｔｅｒｅｓｔｉｎｗａｖｅｌｅｎｇｔｈ ｄｉｖｉｓｉｏｎｍｕｌｔｉｐｌｅｘｉｎｇ (ＷＤＭ )ｓｃｈｅｍｅｓｆｏｒｆｉｂｒｅ ｏｐｔｉｃｃｏｍｍｕｎｉｃａｔｉｏｎｓ.Ｒｅｓｏｎａｎｔｃａｖｉｔｙｅｎｈａｎｃｅｄ (ＲＣＥ )ｐｈｏｔｏｄｅｔｅｃｔｏｒｓ ,ｆｏｒｔｈｅｉｒｒｅｍａｒｋａｂｌｅｗａｖｅｌｅｎｇｔｈｓｅｌｅｃｔｉｖｉｔｙａｎｄｉｎｃｒｅａｓ…     

On optimum designs of a RCE Si/SiGe/Si MQW photodetector for long wavelength applications

In the present paper, performance analysis of a resonant-cavity-enhanced Si/Si_1–y Ge _y /Si multiple quantum well photodetector has been carried out. The effects of material parameters of active Si_1–y Ge _y layers and carrier trapping by the potential barriers at the heterointerfaces of Si/Si_1–y Ge _y /Si quantum wells on the bandwidth (BW) and Responsivity of the photodetector have been investigated using numerical simulation. Results on possible optimum designs of the photodetector have been suggested to maximize BW-quantum efficiency product.     

ZnO基紫外探测器的制作与研究

利用新型的等离子体辅助金属有机化学气相沉积(P-MOCVD)系统在蓝宝石、硅等衬底上生长出具有单一c轴取向、高阻的ZnO薄膜,利用添加的等离子体发生装置,进行氮掺杂获得高阻ZnO薄膜。利用ZnO的宽禁带与高光电导特性,结合MSM(金属-半导体-金属)结构器件响应度高、速度快、随偏压变化小、工艺简单、易于单片集成等优点,制作了ZnO基紫外探测器,器件规格为80 μm×100μm,电极为叉指式电极。测试中采用500 W的氙灯做测试光源,探测器的Ⅰ-Ⅴ特性曲线显示;正向偏压下探测器的暗电流及光照电流与外加偏压呈线性增长。不同波长下的响应曲线显示:探测器对紫外波段有响应,响应峰值在375nm附近。     

Experimental and Simulation Analysis of Two-Tone and Three-Tone Photodetector Linearity Characterizing Systems

Two measurement techniques are investigated to characterize photodetector linearity. A model for the two-tone and three-tone photodetector systems is developed to thoroughly investigate the influences of setup components on the measurement results. We demonstrate that small bias shifts from the quadrature point of the modulator will induce deviation into measurement results of the two-tone system, and the simulation results correspond well to experimental and calculation results.     

InGaAsP分别限制量子阱激光器

长波长InGaAsP量子阱激光器,以其低阈值、窄光谱线宽和高的调制频带宽等优良特性而成为大容量通信的基础。为此,我们利用低压MOVCD技术生长了1.62μm和1.3μm的InGaAsP材料,测得其77K光荧光(PL)谱线半峰高宽分别为18.7meV和28meV.利用X射线双晶衍射测得两种材料的晶格失配度不大于1×10^-3.并生长了四个不同阱宽的InGaAsP/InP量子阱结构,测得77K温度下的PL谱,分析了阱宽对发光波长及半峰宽的影响,并提出在量子阱激光器中减小界面层影响的方法。在此基础上,生长了分别限制量子阱激光器结构,并利用质子轰击制备出条形结构激光器,测得其最低阈值电流为100mA.直流工作光谱峰值波长为1.52μm左右,单面输出外微分量子效率约为36%.     

细菌视紫红质生物膜光电探测器

细菌视紫红质是一种光能存储与能量转换的生物膜蛋白质分子在光作用下，参产生极为迅速的电荷分离和蛋白质电响应信号，这种光电信号不同于一般无机光电材料的光电响应特征。用电泳法在ＩＴＯ导电玻璃上沉积出定向细菌视紫红质薄膜，与铜电极构成夹细菌视紫红薄膜和导电凝胶结构的光电探测器。     

1.55μmSi_(1-x)Ge_x光波导与Si_(1-x)Ge_x/Si多量子阱探测器集成的优化设计

对１．５５μｍ波长的Ｓｉ１－ｘＧｅｘ光波导和Ｓｉ１－ｘＧｅｘ／Ｓｉ多量子阱（ＭＱＷ）红外探测器的集成器件结构进行了系统的分析和优化设计。优化结果为：１）对Ｓｉ１－ｘＧｅｘ光波导，Ｇｅ含量ｘ＝０．０５，脊宽、高和腐蚀深度分别为８、３和２．６μｍ；２）对Ｓｉ１－ｘＧｅｘ／Ｓｉ多量子阱红外探测器，Ｇｅ含量ｘ＝０．５，探测器由厚度为５５０ｎｍ、２３个周期的６ｎｍＳｉ０．５Ｇｅ０．５＋１７ｎｍＳｉ组成，长度约２ｍｍ。结果表明，这种结构器件的内量子效率可达８８％。     

高精度光电探测器的线性测量

介绍了一种高精度的光电探测器线性测量系统,讨论了线性测量的方法,确定以光束叠加法为线性测量系统的基础.设计了测量系统,以944 nm激光器为光源,测量了Si陷阱探测器和InGaAs陷阱探测器的非线性因子.实验结果表明,利用该系统在0.1～200μW的入射光功率范围内.Si陷阱探测器非线性因子平均值小于0.009%,联合不确定度小于3.18%;InGaAs陷阱探测器非线性因子平均值小于0.6%,联合不确定度小于6.87%.实验结果证明该系统可以作为高精度光电探测器线性测量装置.     

RCE photodiodes at wavelength band of 1.06 μm

Resonant cavity enhancement (RCE) typed optical detector and modulator which operating at wavelength band of 1.06 μm is reported. The peak quantum efficiency of detector is reasonably high as 50% without bias, and the photocurrent contrast ratio of modulator is 3.6 times at -3.5 V as compared to 0 V. The incident angle dependence of RCE device's photoelectric response is investigated carefully.     

ZnO肖特基势垒紫外探测器

以p-Si(111)为衬底,用水热法首次制得六棱微管ZnO。并以此为有源区利用平面磁控溅射技术沉积得到Ag叉指状电报,从而制作了Ag／n-ZnO肖特基势垒结紫外探测器。对该紫外光探测器的暗电流和365nm波长光照下的光电流、光响应和量子效率进行了测试。测试结果表明：Ag和ZnO六棱管间已形成肖特基接触．其有效势垒高度为0．35eV。无光照时,暗电流很小,当用λ=365nm的光照射Ag/n-ZnO肖特基结时．在5．9V偏压时,光生电流分别为25．6,57．9μA。Ag／n-ZnO紫外探测器有明显的光响应特性和较高的量子效率,在366nm波长处,光响应度达到最大值0．161A／W,量子效率为54．7％。     

Experimental and theoretical investigations of optical properties of GaN/AlGaN MQW nanostructures. Impact of built-in polarization fields

We report the results from detailed optical spectroscopy from MOCVD grown GaN/AlGaN multiple quantum wells (MQWs), as opposed to most previous studies where MBE was employed by means of photoluminescence (PL) technique. In this paper we will present theoretical and experimental results demonstrating how polarization induced electric fields and bound interface charges in GaN/AlGaN MQWs affect the emission peak energy, PL line shape, as well as the emission line width. Theoretically estimated fields in this work are consistent with experimental data. Transition energy of the heavy hole and electron ground state Ee-hh in GaN/AlGaN MQWs were calculated and it is found that it stays in good agreement with the experimental data.     

多量子阱波导的传输和色散特性

本文用Floquet理论分析了多量子阱(阱垒数N>>1)波导的传输和色散特性,给出了适用于TE和TM两种偏振态的等效三层平板波导芯子折射率的解析公式,该公式清楚地说明了多量子阱波导的本征双折射行为。     

谐振腔增强型光电探测器的角度相关特性研究

采用MBE生长In_0.3Ga_0.7As/GaAs和GaInNAs/GaAs量子阱为有源区的器件结构材料,制备出工作在1060nm及1310nm波段的谐振腔增强型光电探测器.对谐振腔增强型光电探测器的空间角度相关特性进行了实验与物理分析,改变光束入射角度,器件谐振接收波长可在大范围调变.     

多量子阱平面光波导的有限元分析

本文利用有限元法分析了多量子阱平面光波导的传播特性,给出了任意阱数多量子阱光波导_TE模和TM模的有效折射率和TE模的强度分布.结果表明:γ(势阱与势垒的厚度比)值的改变,影响波导中导模的模式数目、有效折射率、双折射和强度分布;并发现在某些情况下,均方根近似是不适用的.     

Changes of MQW photoluminescence under alpha particle irradiation

Undoped multiple quantum well (MQW) samples grown by the molecular beam epitaxy method were irradiated by 5.15 MeV energy alpha particles. A strong influence of irradiation on the photoluminescence (PL) intensity was observed in these nearly intrinsic samples: the PL intensity at liquid nitrogen and room temperatures decreased by more than two orders of magnitude at alpha particle fluence of 10¹¹cm ^− 2. The dependence of the PL intensity on irradiation dose is described by a rate equation model that takes into account the generation of nonradiative point centers in barriers and wells of the MQW structure during irradiation.     

低暗电流InGaAs-MSM光电探测器

MSM(金属-半导体-金属)型光电探测器的较低寄生电容和高带宽的特点使得其应用广泛,可用于空间通信、遥感等多方面,但暗电流偏大仍是制约其发展的重要因素.为此,本文研制了100×100μm2面积的InGaAs-MSM光电探测器,通过设计InAlGaAs/InGaAs短周期超晶格和InAlAs肖特基势垒增强结构,将器件暗电流密度降至0.6pA/μm2(5V偏置),改善了目前同类器件的信噪比.对器件光电参数进行了表征:3dB带宽6.8GHz,上升沿58.8ps,1550nm波段响应度0.55A/W,光吸收区域外量子效率88%.分析了短周期超晶格和肖特基势垒增强层对暗电流的抑制机理.     

A Photovoltaic InAs Quantum-Dot Infrared Photodetector

A photovoltaic quantum dot infrared photodetector with InAs/GaAs/AIGaAs structures is reported. The detector is sensitive to normal incident light. At zero bias and 78K, a clear spectral response in the range of 2-7μm has been obtained with peaks at 3.1, 4.8 and 5.7μm. The bandgap energies of GaAs and Al0.2Ga0.8As at 78K are calculated and the energy diagram of the transitions in the Quantum-Dot Infrared Photodetector （QDIP） is given out. The photocurrent signals can be detected up to 110 K, which is state-of-the-art for photovoltaic QDIP, The photovoltaic effect in our detector is a result of the enhanced band asymmetry as we design in the structure.     

快速光电探测器脉冲响应的电光取样测量

建立了半导体激光器电光取样系统。选择１．３μｍ，ＩｎＧａＡｓ增益开关半导体激光器作为取样光源，利用微带ＧａＡｓ衬底的纵向电光效应作为电光取样器，测量了ＩｎＧａＡｓ／ＩｎＰ雪崩二极管的脉冲响应特性。分析表明，本系统具有０．３５ｍＶ／√Ｈｚ的电压灵敏度和９ｐｓ的时间分辨率。     

Giant exciton resonance reflectance in Bragg MQW structures

We have studied the reflectivity from heterostructures with a finite number of equidistant quantum wells. A giant amplification of the reflectance has been observed in the multiple quantum wells satisfying the Bragg condition kd=π, where k is the light wavevector in the exciton resonance region and d is the period of the structure. No difference in the photoluminescence intensity and decay time has been found on the Bragg and "anti-Bragg" (kd=π/2) structures.