导带不连续性对InGaAsP/InGaAs UTC PD带宽的影响

研究了导带不连续性对InGaAsP/InGaAs单行载流子高速光探测器(UTC-PD)的3dB带宽的影响。研究结果表明,由于导带不连续性的存在,使得3dB带宽降低。导带不连续性越大,3dB带宽越低。通过增加隧穿系数、收集层厚度、收集层掺杂浓度和减小吸收层掺杂浓度可以在一定程度上消除导带不连续性带来的不利影响。研究结果还表明,增加隧穿系数、收集层厚度和减小吸收层掺杂浓度这三种方法在消除导带不连续性不利影响的同时又有各自的缺点,而适当增加收集层掺杂浓度是最为有效的一种方式。该研究结果可以为UTC-PD的设计提供理论指导,特别是采用UTC结构的波导型光电二极管。     

110～200GHz频段InP单行载流子光电二极管

设计制备了一种基于InP材料低偏压工作的单行载流子光电二极管(UTC-PD),该器件的工作频率范围为110～200 GHz。为提升器件的带宽特性，UTC-PD芯片的吸收层采用p型高斯掺杂的InGaAs材料，芯片的InP衬底减薄至12μm。UTC-PD采用背照式的方式输入光信号。通过倒装焊的形式将芯片安装在厚度为50μm的AlN基片上的共面波导焊盘上进行测试。在-3 V偏压和1.55μm波长输入光条件下，制备器件的响应度超过0.2 A/W;在110 GHz处获得最高输出功率为-5.6 dBm, 197.83 GHz处的输出功率最低为-10.6 dBm。     

基于DBR增强的850nm GaAs/AlGaAs单行载流子光电探测器

高速850 nm GaAs/AlGaAs面入射型单行载流子光电探测器(PD)是短距离光链路中的重要器件,面临着带宽和响应度之间的相互矛盾。报道了一种基于分布布拉格反射器(DBR)增强的GaAs/AlGaAs单行载流子光电探测器(UTC-PD)。DBR由20个周期的高/低Al组分的Al_xGa_1-xAs三元合金组成,可以在830～870 nm范围内形成大于0.9的反射。在AlGaAs DBR的增强下,将GaAs吸收层所需的厚度降低到1 040 nm,兼顾PD对光的吸收率和光生载流子的渡越时间。采用双台面、聚合物平面化、共面波导电极结构制作了UTC-PD器件。该器件在850 nm波长、-2 V偏压下具有19.26 GHz的-3 dB带宽和0.492 6 A/W的响应度。     

单向载流子传输光电探测器模拟

用Atlas软件对单向载流子传输光电探测器(uni-traveling-carrier photodetector,UTC-PD)进行了模拟,研究了器件的基本工作原理,着重讨论了器件性能与外延层结构的关系.设计出的UTC-PD可同时具有高的响应度(≥0.18A/W)和宽的3dB带宽(≥100GHz).与传统的pin光电探测器相比简化了前端电路结构,降低了噪声,节约了成本,可以应用于超高速光互联.     

单向载流子传输光电探测器模拟

用Atlas软件对单向载流子传输光电探测器(uni-traveling-carrier photodetector,UTC-PD)进行了模拟,研究了器件的基本工作原理,着重讨论了器件性能与外延层结构的关系.设计出的UTC-PD可同时具有高的响应度(≥0.18A/W)和宽的3dB带宽(≥100GHz).与传统的pin光电探测器相比简化了前端电路结构,降低了噪声,节约了成本,可以应用于超高速光互联.     

UTC-PD和RTD单片集成的器件模拟研究

单行载流子光电二极管与共振隧穿二极管单片集成器件是一种新型高速光电探测器,也是高速光电单稳双稳转换逻辑电路的一个基本单元。用Atlas软件对该集成电路单元进行了直流和交流特性的模拟研究,模拟得到的3dB带宽最高可达9THz。模拟发现,光照强度、吸收层厚度、掺杂浓度、收集层浓度是影响器件3dB带宽的主要因素。研究了器件材料参数、结构参数与器件3dB带宽之间的关系,并得到在现行工艺下优化后的单行载流子光电二极管和共振隧穿二极管单片集成器件的工艺参数,模拟出3dB带宽为1.03THz。同时,对器件模拟和半导体工艺间的误差进行了分析和估计。这一工作为单行载流子光电二极管和共振隧穿二极管单片集成器件的设计和研制提供了工艺参数基础。     

CMOS图像传感器光电二极管模型

为了更好的对CMOS图像传感器中光电二极管的光电转换物理现象进行研究,需要建立正确合适的光电二极管数学物理模型。通过少数载流子稳态连续方程建立光电二极管的一维物理模型,求解方程后,代入参数在MATLAB中对两层结构的n+/p-sub型和n-well/p-sub型,以及三层结构的p+/n-well/p-sub型二极管进行了计算模拟,得到了3种二极管响应率与波长的关系曲线。最后将结果与实际值进行了对比分析,确认了模型能够在一定程度上反映实际的物理情况。     

基于DPMZM和UTC-PD的宽带太赫兹信号产生及传输研究

为了能够充分利用微波光子倍频优势并简化系统复杂度,提出一种基于双平行马赫-曾德尔调制器(DPMZM)和单行载流子光电二极管(UTC-PD)的宽带太赫兹矢量信号产生及光纤传输方案,通过适当地调整DPMZM直流偏压和调制指数,矢量信号被调制在光波的+3阶边带,本振信号被调制在光波的-3阶边带,并采用VPI软件对方案进行了仿...     

半导体光电二极管和有关器件

半导体结器件(光电二极管、光电晶体管,等等)是0.1微米—1微米波长范围内的一种重要的探测器。光电二极管同光电导体相比,其主要优点是有高频响应。原因在于光电二极管的频率响应是由耗尽层电容和受激载流子的渡越时间所确定,而不是象光电导体那样由少数载流子的寿命或俘获时间所确定。本文阐述半导体结光电探测器的某些性能,重点在光电二极管方面。     

RTD/UTC-PD高速光控MOBILE

单向运动载流子光二极管(UTC-PD)具有高速和大电流的特点,与RTD相结合可构成一高速光控MOBILE,能够应用于80Gb/s的光纤通信、光信息处理和高速光网络中。在详细介绍UTC-PD的基础上,讨论了RTD/UTC-PD光控MOBILE的工作原理、材料结构和制作工艺、电路性能测量等,并进一步将上述结果推广到交流信号情况下RTD/UTC-PD光控MOBILE的瞬态特性。结果表明,存在三个因素影响该单元电路的工作速度,即交流电流效应、开关延迟时间和UTC-PD器件的带宽。     

Monolithic Integration of InP HBTs and Uni-Traveling-Carrier Photodiodes Using Nonselective Regrowth

This paper describes the monolithic integration of InP HBTs and uni-traveling-carrier photodiodes (UTC-PDs) by nonselective regrowth. HBTs are fabricated from nonselectively regrown device layers and UTC-PD subcollector layers, which are grown first on a 3-in InP substrate. This makes it possible to optimize the layer design for the HBTs and UTC-PDs independently and minimize the interconnection between them. The fabricated HBTs have a collector thickness of 200 nm, and they show an f_t of 260 GHz and an f_max of 320 GHz at a collector current density of 2.5 mA/mum². The standard deviations of the f_t and f_max across the wafer are 1.7% and 4.4%, respectively. The length of the interconnection between the HBTs and UTC-PDs can be made as small as 10 mum without any degradation of the regrown-HBT performance. The UTC-PDs fabricated on the same wafer exhibit a 3-dB bandwidth of 100 GHz and an output voltage of 1.0 V. There is no drawback in the performance of either device, as compared with that of discrete devices. We also demonstrate 100-GHz optical-input divide-by-two optoelectronic integrated circuits (OEICs) consisting of InP HBTs and a UTC-PD using this technique. These results indicate that the nonselective regrowth is promising for application toward over 100-Gb/s OEICs.     

1.55-μm wavelength periodic traveling-wave photodetectorfabricated using unitraveling-carrier photodiode structures

We report the first periodic traveling-wave photodetector fabricated by using unitraveling-carrier photodiodes (UTC-PDs). The photodetector comprises three UTC-PDs with a 0.06-μm absorption layer that is periodically arranged along a coplanar waveguide transmission line. The photoresponse of the photodetector is three times larger than that of a single UTC-PD. A photodetector with terminal resistors at the input end achieves a 3-dB bandwidth of 115 GHz at 1.55 μm. This is almost the same value as that for a single UTC-PD. For one without terminal resistors, the 3-dB bandwidth degrades to 56 GHz as a result of the backward-propagating microwave being reflected at the input end. These results suggest that the photodetector is well designed with both velocity and impedance matchings     

High Output Saturation and High-Linearity Uni-Traveling-Carrier Waveguide Photodiodes

Waveguide uni-traveling-carrier photodiodes (UTC-PDs) have been fabricated and tested. Output saturation currents greater than 40 mA at 1 GHz are demonstrated for a 10 mumtimes150mum photodiode (PD). The third-order intermodulation distortion is also measured and exhibits a third-order output intercept point of 43 dBm at 20 mA and 34 dBm at 40 mA for this same PD. UTC-PDs with geometries of 5 mumtimes100 mum and 10 mumtimes100 mum are also compared and it is shown that a wider waveguide PD has improved saturation characteristics due to the lower optical power density which reduces the saturation at the front end of the device     

引入了流体动力学模型的单载流子光探测器的优化

本文中,通过引入了流体动力学模型对单载流子光探测器的特性进行了模拟,并对模拟结果做了分析和研究。在此基础上,提出了改进器件的方法,进而得到了一个优化的器件,优化后的器件将带宽提高到了原器件的两倍。     

The Monolithic Integration of a Wavelength-Demultiplexer With Evanescently Coupled Uni-Traveling-Carrier Photodiodes

In this letter, we discuss a novel integration of a wavelength demultiplexer with a pair of uni-traveling-carrier photodiodes (UTC-PDs). With this integrated module, we could separate incoming wavelengths of 1530 and 1550 nm, which are near the wavelengths utilized for digital and analog signal transmission in coarse wavelength-division multiplexing (CWDM) systems. The integrated UTC-PDs exhibited the following advantages: a wide 3-dB bandwidth (25 GHz), a reasonable responsivity (0.35 A/W), and a high-saturation-current (>17 mA). A low level of radio frequency crosstalk between the two photodiodes (less than -15 dB) could also be achieved for a wide frequency range (near DC to 40 GHz). This is low enough for the multichannel receivers in a WDM broadcast system. In addition, by use of our module, we demonstrated digital/analog signals co-transmission and demultiplexing with speeds of 2.5 Gb/s at optical wavelengths of 1530 and 1550 nm.     

Output Saturation and Linearity of Waveguide Unitraveling-Carrier Photodiodes

Waveguide unitraveling-carrier photodiodes (UTC-PDs) with different absorber and collector layer doping levels have been fabricated and characterized. These photodiode (PD) structures are fabricated on a platform that allows for the monolithic integration of multiquantum-well optical phase modulators and couplers for realizing novel coherent receivers. Compared to PD A, PD B has a lower and more graded p-doping profile in the absorber layer and also a higher n-doping level in the collector layer. For PD B a larger field is induced in the absorber layer at high photocurrent levels. Also the higher n-doping in the collector layer is adequate for providing charge compensation. For PD B, there is an enhancement in the RF response as the photocurrent level is increased. At a frequency of 1 GHz, the saturation current for PD A is around 65 mA and that for PD B is around 63 mA. For PD B, the third-order output intercept point at photocurrent levels of 30 and 40 mA is 37.2 and 34.9 dBm, respectively. That for PD A is 35.8 and 30.4 dBm. PD B is, therefore, favorable for linear operation at high current levels.     

Structure optimization of a uni-traveling-carrier photodiode with introduction of a hydro-dynamic model

Characteristies of a uni-traveling-carrier photodiode(UTC-PD)are investigated.A hydro-dynamic model is introduced which takes into account the electrons'velocity overshoot in the depletion region.which is a more accurate high speed device than using the nodal drift-diffuse model.Based on previOUS results,two modified UTC-PDs are presented,and an optimized device is obtained,the bandwidth of which is more than twice that of the original.     

Uni-travelling-carrier photodiode performance with X-band modulation at high optical power

We have fabricated and characterized backside illuminated uni-travelling-carrier photodiodes (UTC-PDs) and obtained average photocurrents exceeding 140mA and very high peak-to-peak voltages of 7.4V over 50/spl Omega/ at 10Gb/s with no indication of reduced bandwidth. Nonlinear distortion at 10 GHz are also measured for high photocurrents, up to 140mA, while retaining third-order intercept point above 30dBm.     

双偏振双波长混合应变量子阱激光器

本文报道了以混合应变量子阱结构为有源区的激光器。对有源区分别采用体材料、匹配量子阱、压应变量子阱和混合应变量子阱结构的激光器进行了比较。混合应变量子阱激光器能同时工作于两种偏振模式，而且两种偏振模式的激射波长不同。结合实验结果，我们可以看出在混合应变量子阱结构中，从偏偏自发辐射谱峰值长差不能推断两种量子陆的能带填充效应大小。     

聚合物/小分子有机光伏电池活性层形貌调控研究进展

近年来,基于新的有机半导体材料的合成、器件结构的优化以及对太阳电池活性层形貌的有效调控,有机光伏电池(OPV)得到了迅速的发展。目前基于聚合物/小分子共混体系的单结OPV的光电转换效率已经超过18%。首先,概述了聚合物/小分子OPV的研究进展;接着,介绍了OPV的工作原理和相分离机理,并分析了OPV的光电性能、活性层形貌特征参数以及相分离过程这三者之间的关系;其次,探讨了不同物理调控手段对活性层形貌的影响,主要介绍了调节溶液的聚集、成膜过程中优化活性层形貌以及薄膜后处理等优化活性层的方法,重点介绍了聚合物/小分子OPV的活性层形貌调控的方法;最后,对OPV未来的发展方向进行了展望。