弱电导材料中载流子迁移率的测量方法研究

为了精确测定弱电导材料中载流子迁移率,采用渡越时间方法测量了8-羟基喹啉配合物（Alq3）的载流子迁移率,对渡越时间方法需要的实验条件进行了理论分析和实验验证,讨论了激发光源的波长、单脉冲能量以及测量电路的积分时间常数的选取对材料载流子迁移率测量结果的影响。结果表明,采用渡越时间方法测量弱电导半导体材料中载流子迁移率时,只有严格选取合适的测量条件,才可能获得准确、可靠的测试结果。此结论有助于对有机电致发光器件载流子迁移率进行精确测定。     

半导体激光器阈值行为的研究

采用平均场近似，用洛仑兹函数来描述增益曲线和自发辐射，得到了多模速率方程组的隐式解析解。在此基础上，着重对阈值附近半导体激光器的载流子密度、输出功率以及阈值电流等重要特性进行了研究。理论和实验结果吻合得很好。     

长基区晶体管的磁敏感效应

当n~+-i-n~+型晶体管的基区宽度大于载流子扩散长度时,在磁场中它的集电极电流具有很高的磁灵敏度.本文从输运基区载流子连续方程式出发导出了载流子在磁场中的分布,从而导出了集电极电流、电流增益α和β随磁场变化的关系式,并建立了磁灵敏度公式.本文将理论同锗长基区滋晶体管的实验曲线和数据进行了比较,其结果表明理论和实验曲线基本相符合.     

非磁控条件下真空开关真空度测量的原理及应用

摈弃传统真空开关管内真空度测量所必需的磁场条件,在真空开关触头两端加足够高电压,导致气体分子在真空极化的基础上完全电离形成载流子信号.经研究表明,此载流子信号与真空开关管内真空度有关.通过理论建模与实验比较,验证该理论的可应用性.与常用的磁控法测量真空开关的真空度相比,该方法具有易实现,准确度高的优点.     

双注入长二极管的磁灵敏度理论

本文用载流子连续方程研究了在一个侧面设置高复合中心的双注入长“基区”二极管的磁阻效应,导出了载流子有效寿命、伏安特性同磁场强度的函数关系和磁灵敏度的表达式,并分别给出了强弱磁场下的有关近似表达式。实验结果表明,理论同实验相符合。     

碲镉汞光导器件的交叠结构与性能

光数载流子扫出效应是限制碲镉汞（ＨｇＣｄＴｅ）光导器件性能提高的重要因素之一。交叠结构的光导器件能有效地消除少数载流子扫出效应，就结构的尺寸问题，进行了理论分析和实验，实验结果与理论符合，器件呼应率有较大的提高。     

调制激光激发PN结少数载流子分布及频域响应特性研究

为建立载流子辐射检测Si基太阳能电池的理论模 型,基于太阳能电池非线性耦合方程对调制激光激 励下Si太阳能电池过剩少数载流子的空间分布与频率响应特性进行了仿真分析,对基区、耗 尽层和发射区 的载流子分布与超带宽调制激光的波长、功率密度和调制频率的关系进行了定量研究,通过 仿真结果选定 调制激光的最佳参数范围,进行了载流子辐射频域响应和载流子寿命对频域响应影响的仿 真计算。仿真 结果表明,过剩载流子浓度随扫描频率的增加呈现非线性特征,所用仿真模型对激发参数和 输运参数有较高 的灵敏度。最后对Si基太阳能电池片进行了扫频验证实验,实验结果与仿真结果符合良好, 表明所使用的 仿真方法能够预测载流子辐射技术的检测结果,可用于对调制载流子辐射检测技术仿真和结 果预测。     

用于激光脉冲整形的电脉冲产生技术

介绍了一种用于激光脉冲整形的超宽带脉冲产生方法.电路中利用阶跃恢复二极管(SRD)载流子可控、截止速度快的特点,采用对阶跃恢复二极管进行串并联相结合的方法设计了超宽带脉冲产生电路.给出了实际电路的测试结果,并且对实验结果在物理层面上进行了理论分析,实验结果与理论分析结果吻合.此脉冲产生电路可输出幅度约10V,脉冲宽度约...     

超快泵探针对GaAs中X射线诱导的瞬态光学反射率变化的探测

理论估算并实验验证了在X射线脉冲激发下低温砷化镓的光学折射率调制特性。泵浦-探针实验表明,低温砷化镓中存在的高密度复合缺陷大大减小了载流子寿命,使超热电子的弛豫时间小于110-12 s,载流子的复合时间小于 210-12 s,折射率的扰动时间约为210-12 s。通过理论分析,给出了自由载流子和俄歇效应对该弛豫过程的定量估算,与实验结果吻合较好。该研究表明低温生长砷化镓是一种有效的可用于单次瞬态皮秒时间分辨X射线探测的材料。     

用非相干光时间延迟四波混频测量载流子复合时间

本文首次报道了用非相干光时间延迟四波混频测量载流子复合时间的理论，实验证实了该理论的正确性，测得ＰｂＳ超微粒子和ＣｄＳ：Ｃｕ的载流子复合时间分别为１．５６ｎｓ和０．８ｎｓ     

Impedance characteristics of quantum-well lasers

We derive theoretical expressions for the impedance of quantum-well lasers below and above threshold based on a simple rate equation model. These electrical laser characteristics are shown to be dominated by purely electrical parameters related to carrier capture/transport and carrier re-emission. The results of on-wafer measurements of the impedance of high-speed In_0.35Ga_0.65 As/GaAs multiple-quantum-well lasers are shown to be in good agreement with this simple model, allowing us to extract the effective carrier escape time and the effective carrier lifetime, and to estimate the effective carrier capture/transport time     

Computer-aided study of steady-state carrier lifetimes under arbitrary injection conditions

The steady-state minority and majority carrier lifetimes are calculated using an exact steady-state equivalent circuit model. The exact majority and minority carrier lifetimes are calculated as functions of position in a diffused silicon P/N junction diode doped with zinc, and as functions of bias voltage or injection level. Factors which affect carrier lifetimes are pointed out and illustrated. Lifetimes due to the presence of multiple energy level Shockley-Read-Hall centers are also discussed. The exact carrier lifetimes at very low and very high injection levels computed from this model agree well with those calculated from the analytical expressions derived by Shockley and Read.     

DC应力n-MOSFET热载流子退化的1/f噪声特性

研究了DC应力n.MOSFET热载流子退化的Sfγ噪声参量.提出了用噪声参数和Sfγ表征高、中、低三种栅应力下n-MOSFET抗热载流子损伤能力的方法.进行了高、中、低三种栅压DC应力下热载流子退化实验.实验结果和本文模型符合较好.     

MIMO-OFDM系统载波同步的空间分集算法

在分析MIMO-OFDM系统载波频偏信号模型基础上,提出了基于单个OFDM前导子符号相关的MIMO-OFDM载波同步的空间分集算法,从链路级研究了易于实现的MIMO-OFDM系统载波同步算法,在无线多径Rayleigh信道COST207模型下,车速分别为10km/h 和120km/h时,给出了MIMO-OFDM系统载波同步分集算法的仿真结果.     

Theory of hot carrier effects on nonlinear gain in GaAs-GaAlAslasers and amplifiers

A concise and straightforward model of nonlinear grain based on the carrier heating effect in semiconductor lasers is presented. The problem is formulated using the density matrix approach and includes a priori the effect of free-carrier absorption. Coupled field-medium equations involving photon densities, carrier densities, and carrier temperatures are derived using the results of the density matrix method. The propagation of ultrashort pulses in laser amplifiers is studied and a qualitatively new model along with results on the transient gain recovery dynamics are presented. The model accounts for the wavelength dependence of the asymmetric part of the nonlinear gain observed in direct mixing experiments observed in semiconductor lasers     

MINIMOS 3: A MOSFET simulator that includes energy balance

We present a model for hot carrier transport which is implemented in the device simulator MINIMOS 3. A brief resume of the model is given. We present various results which were calculated with this new model. We show that the I-V characteristics of a MOSFET can be calculated from Leff= 10 µm down to Leff= 0.9 µm with one parameter set. Modifications of carrier and current distributions are presented that show how hot carrier effects tend to smooth these distributions. Implications are discussed how a self-consistent carrier temperature can be used to model impact ionization and oxide injection.     

Self-Consistent Model and Numerical Analysis of VCSEL's Laser Diodes

A self-consistent model of vertical-cavity surface-emitting lasers (VCSEL's) is presented in this paper, in which the carrier diffusion rate equation, the photon density rate equation, and the thermal conduction equation are considered simultaneously. The nonuniform heat flux density distribution in the active region due to the current-spreading effect is taken into account. The effects of temperature on gain and transparency carrier density are also included in this model. It is nonlinearly and self-consistently solved in the Matlab environment. The transient and lateral distribution characteristics of the carrier and photon densities and the junction temperature are investigated. Some interesting results are gotten and analyzed.     

基于有效态密度的MOS结构电荷控制模型

从载流子在 MOS结构反型层内的分布出发 ,利用表面有效态密度 ( SLEDOS:SurfaceLayer Effective Density- of- States)的概念 ,在经典理论框架内建立了包含载流子分布对表面势影响的电荷控制模型 .该模型包含了强反型区表面电势的变化对载流子浓度的影响 ,采用了一种新的高效的迭代方法 ,具有较高的计算效率和足够的精度要求     

一种新的MOS结构量子化效应修正模型

从载流子在 MOS结构反型层内的经典分布和量子化后的子带结构出发 ,提出了经典的和量子化的表面有效态密度 (SL EDOS:Surface layer effective density- of- states)的概念。利用表面有效态密度的概念建立了经典理论框架和量子力学框架内的电荷分布模型。该模型包含了强反型区表面电势的变化对载流子浓度的影响 ,具有很高的计算效率和稳定性。在模型基础上 ,研究了量子化效应对反型层载流子浓度和表面电势的影响。     

GNSS卫星信号模拟器码和载波NCO研究与实现

NCO是卫星信号模拟器中频信号处理的关键部分。介绍了GNSS卫星信号模拟器码NCO和载波NCO的原理及作用,建立DDS模型,确定基本参数并根据参数设计了码NCO和载波NCO基本结构。给出了码NCO和载波NCO的实现过程,利用verilog在Xilinx’ISE11.2和modelsim6.5中完成载波NCO和码NCO的设计和仿真,在FPGA中进行了实现,并给出仿真波形和信号频谱图。本码NCO和载波NCO模块已应用于某型GNSS模拟器样机,通过程序仿真与样机测试,证明本码NCO和载波NCO模块性能满足GNSS卫星信号模拟器系统需求。