1.1～1.6μm光通信系统用的p-i-nFET混合光接收器

<正> 最近美国邮电研究中心报导了具有高达1.6μm 波长响应的低电容的汽相外延 InGaAs/InP p-i-n 光电二极管和 p-i-n FET 混合光接收器的制备。以前该研究中心报导过波长1.3μm 的 InGaAs/InPp-i-n 光电二极管和 GaAsMESFET前置放大器混合集成的光接收器,其典型的接收灵敏度在140和 280Mbit/sec 下达到-44和-40dBm,误码率为10~(-9)。     

MOS器件的超短脉冲激光辐照效应

电荷耦合器件(CCD)的高敏感性使其易受到激光脉冲的干扰甚至损伤.在理论分析了影响MOS结构光生电荷量因素的基础上,数值仿真了MOS器件的光生电荷量以及响应电压和电流随激光脉宽和平均功率变化的关系;实验研究了CCD对不同参数激光脉冲的光电响应特性.数值仿真表明,MOS器件的光生电荷量以及峰值响应电压和电流随激光脉冲的平均功率和脉宽的增大而增大,并且响应电压和电流有拖尾现象.实验结果显示,脉冲越短,CCD的响应阈值越低.研究结论对超短脉冲激光在光电成像方面的应用具有一定的意义.     

高灵敏紫外激光脉冲能量在线检测系统设计

介绍了一种基于PIN光电二极管的紫外激光脉冲能量在线检测系统。首先,采用激光主光路外的检测光实现激光脉冲能量的无损在线响应;其次,采用高速高精度积分电路将响应光电流处理为电压峰值;最后,利用激光系统的同步触发信号进行检测时序设计从而获得精确的激光脉冲前后的检测系统输出差值,经过计算后获得精确的激光脉冲能量。检测系统在248 nmKrF和308 nmXeCl准分子激光器上进行了测试,实现了对0~200 Hz重复率运行的准分子激光能量在线无损检测,测量结果与输出端外置能量计测得结果相对比,相关性与可重复性一致,满足应用需求。     

VNPN激光辐射效应模拟分析

通过仿真模拟脉冲激光对半导体器件光生载流子的影响,重点研究纵向NPN三极管(VNPN)的激光辐照效应。光照强度较小时,只有集电结反偏,而发射结处的光生电动势不足以抵消发射结的内建电势,发射结尚未开启,器件工作在以集电结为主的二极管模式;光照强度增加时,发射结逐渐开启,器件工作在三极管模式;光照强度进一步增大,由于外部限流电阻的作用,集电极电流达到饱和,器件工作在以发射结为主的二极管模式。因此,随着光照强度的增加,VNPN器件的激光辐射效应经历三个阶段,其响应曲线呈非线性变化。改变VNPN的尺寸和脉冲激光的参数,会影响器件进入三极管模式的临界点,改变非线性响应的触发光照强度,体现了器件对激光辐照效应的敏感性。     

皮秒脉冲激光照射下碲镉汞光伏红外探测器的负光伏响应新现象

利用皮秒脉冲激光激发碲镉汞线列探测器上的光敏元,发现光伏响应表现为在最初大约15 ns范围内首先形成一个明显的负光生电压的响应谷,之后才演变为正的光伏响应峰.改变入射激光脉冲的光子能量发现,无论是光子能量大于禁带宽度的单光子吸收跃迁还是小于禁带宽度的双光子吸收跃迁,器件的光伏响应随时间的演变均表现出类似的规律.用光阑对探测器的受光面积进行限制将使负的光生电压减弱并接近消失.结合探测器线列的电极分布构形,将负光伏响应指认为p-电极的肖特基接触所致.利用该方法有可能对p-电极是否形成欧姆接触进行判定,其灵敏度应远高于常规的电学测量方法.     

皮秒脉冲激光照射下碲镉汞光伏红外探测器的负光伏响应新现象

利用皮秒脉冲激光激发碲镉汞线列探测器上的光敏元,发现光伏响应表现为在最初大约15 ns范围内首先形成一个明显的负光生电压的响应谷,之后才演变为正的光伏响应峰.改变入射激光脉冲的光子能量发现,无论是光子能量大于禁带宽度的单光子吸收跃迁还是小于禁带宽度的双光子吸收跃迁,器件的光伏响应随时间的演变均表现出类似的规律.用光阑对探测器的受光面积进行限制将使负的光生电压减弱并接近消失.结合探测器线列的电极分布构形,将负光伏响应指认为p电极的肖特基接触所致.利用该方法有可能对p电极是否形成欧姆接触进行判定,其灵敏度应远高于常规的电学测量方法.     

高重复率脉冲激光能量的检测装置

高重复率脉冲激光能量检测装置是根据图1所示的原理制成的。硅光二极管 D 受脉冲激光照射后产生脉冲的光电流,对电容器 C 充电,电容器两端电压 V 和电量 Q 有如下关系:Q=CV 而电量 Q 是对应于激光的能量 W,即有 Q=KW,K 是硅光二极管光电转换常数。然后电容器上的电量通过 RC 放电,放电曲线的面积就代表激光能量,这样就把测量激     

石墨烯纳米带p-i-n结构太赫兹探测器的设计

研究了石墨烯纳米带横向p-i-n结构探测器对太赫兹波的响应特性,基于载流子输运方程和泊松方程,建立了考虑迁移、扩散、生成、复合等载流子运动的太赫兹探测器数学模型。根据该模型,对石墨烯纳米带横向p-i-n结构的太赫兹波响应进行了仿真,获得了反向栅压诱导生成的p-i-n二极管的能带图;进而探讨了纳米带宽度、i区长度及偏置电压对响应电流的影响,分析表明石墨烯纳米带带隙随宽度增大而减小,响应频率减小;i区长度与载流子寿命匹配时响应电流达到峰值;光电流随偏置电压的增大而增大,并趋于饱和。     

1.54μm APD光电探测器组件的研制及应用

主要从长波长人眼安全测距方面讨论和研究了InGaAs雪崩光电二极管的前置放大器的电路原理和参数的设计以及光电探测器组件混合集成.着重从激光测距方面的应用探讨了由InGaAs雪崩光电二极管组成的激光接收器的应用电路的选择和设计.从测距使用的角度对InGaAs雪崩光电二极管的光电特性与偏置电压的关系进行了测试,从而了解该器件与硅雪崩二极管的光电性能的差异,从而为更好的应用InGaAs雪崩光电二极管提供参考和依据.研制的InGaAs雪崩光电二极管探测器组件及接收器在激光测距机中进行了测距应用,在激光能量为7毫焦耳测距集中进行测距,初步达到了要求.     

激光选择聚焦的响应增强型光电探测器

介绍了一种利用激光选择聚焦的结构来增强光电探测器的光电响应的方法。通过采用工作在传输模式的振幅型菲涅耳波带片,获得了较高的激光收集效率,同时也较好地抑制了背景光。当激光入射时,集成了菲涅耳波带片的InGaAs/InP p-i-n 光电探测器和InGaAs/InP 雪崩光电二极管的响应分别增强了36 倍和4 倍,而当模拟自然光的卤钨灯照射时,集成了菲涅耳波带片的两类光电探测器的响应均被抑制了30%。集成了菲涅耳波带片的探测器显现出对激光信号的较强吸收,对模拟自然光的卤钨灯光源的明显抑制。     

Nonlinear pulse response of p-i-n photodiode caused by the change of the bias voltage

An analytical expression is derived for nonlinear response of a p-i-n photodiode, commonly used in optical communications. Nonlinearity is caused only by the change of bias voltage, in case of pulse light excitation. The response time increases slowly with increasing the incident pulse power as a result of this nonlinearity. It is assumed in calculations that the optical excitation is not so strong to cause space charge redistribution.     

Frequency conversion of optical signals in p-i-n photodiodes

A planar InGaAsP/InGaAs/InGaAsP p-i-n photodiode has been fabricated and used for frequency conversion of two optical signals. Nonlinear properties of the photodiode have been investigated. It is shown that photodiode responsivity R(V) dependence on bias voltage can be characterized by a parameter of the nonlinearity A, which is equal to R(V)middotR'(V) and the maximal conversion efficiency is achieved at the bias voltage where the parameter A has the maximal value     

Flip-chip planar GaInAs/InP p-i-n photodiode array for paralleloptical transmission

A back-illuminated planar GaInAs/InP p-i-n photodiode array with a simple fabrication process was developed for application to parallel optical transmission. Four p-i-n photodiodes were integrated in the array. The average capacitance and dark current were as low as 0.12 pF and 8 pA, respectively, at -5 V. At a 1.55-μm wavelength, the quantum efficiency of each photodiode was over 80%. The cutoff frequency was 8-10 GHz with four photodiodes when the bias voltage was -3 V and the load resistance was 50 Ω. Crosstalk between channels was -12 dB at the cutoff frequency and -45 dB at 1 GHz     

Numerical modeling of energy balance equations in quantum well AlxGa1-xAs/GaAs p-i-n photodiodes

The energy balance equations coupled with drift diffusion transport equations in heterojunction semiconductor devices are solved modeling hot electron effects in single quantum well p-i-n photodiodes. The transports across the heterojunction boundary and through quantum wells are modeled by thermionic emission theory. The simulation and experimental current-voltage characteristics of a single p-i-n GaAs/Al _xGa_1-xAs quantum well agree over a wide range of current and voltage, The GaAs/Al_xGa_1-xAs p-i-n structures with multi quantum wells are simulated and the dark current voltage characteristics, short circuit current, and open circuit voltage results are compared with the available experimental data, In agreement with the experimental data, simulated results show that by adding GaAs quantum wells to the conventional cell made of wider bandgap Al_x Ga_1-xAs, short circuit current is improved, but there is a loss of the voltage of the host cell, In the limit of radiative recombination, the maximum power point of an Al_0.35Ga_0.65As/GaAs p-i-n photodiode with 30-quantum-well periods is higher than the maximum power point of similar conventional bulk p-i-n cells made out of either host Al_0.35Ga_0.65As or bulk GaAs material     

Easily manufactured high-speed back-illuminated GaInAs/InP p-i-n photodiode

A back-illuminated planar GaInAs/InP p-i-n photodiode has been fabricated with a simple fabrication process to obtain a high-speed detector. The photodiode has a capacitance as low as 54 fF, a dark current of about 3 pA, and a quantum efficiency of 74% at a 1.55- mu m wavelength. A cutoff frequency of 31 GHz was obtained when the photocurrent was about 500 mu A and the bias voltage was -10 V.<>     

A monolithically integrated AlGaAs/GaAs p-i-n/FET Photoreceiver by MOCVD

An AlGaAs/GaAs p-i-n photodiode and a GaAs FET have been monolithically integrated on a GaAs substrate by using the metal-organic chemical vapor deposition (MOCVD) technique and by applying a new interconnection technique. A current amplification characteristic consistent to the device parameters has been demonstrated. This result indicates a suitability of MOCVD to realize the monolithic integration of p-i-n/FET photoreceiver.     

Large-area lateral p-i-n photodiode on SOI

Results of a large-area, low-capacitance lateral p-i-n photodiode in silicon-on-insulator (SOI) are presented. This photodiode possesses an antireflection coating optimized for blue light and is therefore appropriate for scintillation detector applications. An average external quantum efficiency of 78.6% and 68.4% is achieved for λ=430 nm and 400 nm, respectively. The rise and fall times of the lateral p-i-n photodiode for light with a wavelength of 400 nm are 9.7 ns and 11.2 ns, respectively. The capacitance of the SOI p-i-n photodiode is 0.72 pF/mm ². This photodiode combines a high quantum efficiency and a low capacitance with a high speed     

Electronic transport properties of the armchair silicon carbide nanotube

The electronic transport properties of the armchair silicon carbide nanotube (SiCNT) are investigated by using the combined nonequilibrium Green's function method with density functional theory. In the equilibrium trans-mission spectrum of the nanotube, a transmission valley of about 2.12 eV is discovered around Fermi energy, which means that the nanotube is a wide band gap semiconductor and consistent with results of first principle calculations.More important, negative differential resistance is found in its current voltage characteristic. This phenomenon orig-inates from the variation of density of states caused by applied bias voltage. These investigations are meaningful to modeling and simulation in silicon carbide nanotube electronic devices.     

扶手椅型碳化硅纳米管的电子输运特性

采用结合密度泛函理论的非平衡格林函数法(4, 4)对扶手椅型碳化硅纳米管的电子输运特性进行了研究。碳化硅纳米管的平衡态透射谱的费米能级附近存在大约2.12 eV的透射谷,这表明碳化硅纳米管是宽带隙半导体材料,与第一性原理的计算结果是一致的;在非平衡态输运特性中,发现了微分负阻效应,该效应是偏压引起态密度变化的结果。论文的研究对碳化硅纳米管电子器件的建模与仿真具有较重要的意义。     

Planar embedded InP/GaInAs p-i-n photodiode for very high-speed operation

Planar embedded InP/GaInAs p-i-n photodiodes have been fabricated by using preferential ion-beam etching for planarizing and embedding the p-i-n photodiode structure in a semi-insulating InP substrate. The stray capacitances caused by a bonding pad and an interconnection have been markedly reduced, which resulted in extremely low capacitance of less than 0.08 pF for a diameter of 20 μm of photosensitive area. It has been demonstrated by an optical heterodyne technique that the photodiode exhibits a maximum cutoff frequency of 14 GHz. This result was analyzed taking the depletion layer thickness into account and has been found to be dominated by the carrier transit time. The demonstrated low capacitance and high-speed response result indicates the suitability of the p-i-n photodiodes not only for a discrete p-i-n photodiode but also for optoelectronic integration.