MSM光探测器的直流特性

在稳态条件下金属-半导体-金属(MSM)光探测器的光电流一维模型可以通过求解电流连续方程和传输方程来建立并求解.在这种条件下,器件内部的载流子分布情况和总体光电流可以得到解析解而不用数值方法求解.本文从电流连续方程和传输方程出发详细推导了这一过程,并将这一结果应用于具体的InGaAs MSM光探测器的直流等效电路模型上,取得了很好的效果.     

MSM光探测器的直流特性

在稳态条件下金属 -半导体 -金属 (MSM)光探测器的光电流一维模型可以通过求解电流连续方程和传输方程来建立并求解 .在这种条件下 ,器件内部的载流子分布情况和总体光电流可以得到解析解而不用数值方法求解 .本文从电流连续方程和传输方程出发详细推导了这一过程 ,并将这一结果应用于具体的 In Ga As MSM光探测器的直流等效电路模型上 ,取得了很好的效果     

MSM结构平面及掩埋叉指电极间电场的分布特性

提出了一种新型具有掩埋电极的金属-半导体-金属(MSM)探测器原型器件结构,并用数值计算的方法研究了其激活层内电场的分布特性,讨论了掩埋电极深度对电场分布的影响,并与传统平面叉指电极结构进行比较,得出该结构对器件性能改善具有重要的作用.     

Monolithically Fabricated OEICs Using RTD and MSM

报道了GaAs基共振隧穿二极管(RTD)与金属-半导体-金属光电探测器(MSM PD)单片集成的两种光电集成电路,并在室温条件下分别测试了RTD器件、MSM器件和集成电路的电学特性.测试表明:RTD器件的峰谷电流比为4;由于改进了在半绝缘GaAs衬底上制作MSM的方法,5V偏压下的电流由原来的2μA增加到了18μA,基本实现了两种电路的逻辑功能.     

GaAs基RTD与MSM光电集成

报道了GaAs基共振隧穿二极管(RTD)与金属-半导体-金属光电探测器(MSM PD)单片集成的两种光电集成电路,并在室温条件下分别测试了RTD器件、MSM器件和集成电路的电学特性.测试表明:RTD器件的峰谷电流比为4;由于改进了在半绝缘GaAs衬底上制作MSM的方法,5V偏压下的电流由原来的2μA增加到了18μA,基本实现了两种电路的逻辑功能.     

金属-半导体-金属光电探测器的瞬态特性分析

给出了金属—半导体—金属光电探测器(MSM—PD)高频特性的等效电路模型，在此模型基础上编写模拟分析程序，分析了探测器相关器件参数对器件截止频率的影响，为探测器与前置放大器的优化匹配提供了理论依据。     

InGaAs/InP红外雪崩光电探测器的研究现状与进展

近年来,量子卫星通信、主动成像等先进技术的应用取得了较大的进展,InGaAs/InP雪崩光电探测器作为信息接收端的核心器件起到了至关重要的作用。本文系统介绍了InGaAs/InP雪崩光电探测器的工作原理,分析了器件结构设计对暗电流特性的影响,对盖格模式下多种单光子探测电路进行了综述,同时对新型金属-绝缘体-金属结构设计的研究进展进行了介绍和展望。     

InGaAs/InP SAGCM-APD的器件模型及其数值模拟

基于泊松方程和载流子连续性方程,导出了InGaAs/InP SAGCM-APD(吸收、渐变、电荷、倍增层分离结构雪崩光电二极管)特性的数学模型,利用数值计算工具对其进行了数值模拟,得到了APD内部电场分布、增益特性、暗电流特性、过剩噪声和增益带宽特性等的数值结果.模拟结果与实际器件特性测量结果相符合,表明运用该模型与数值模拟方法可对不同结构参数的InGaAs/InP SAGCM-APD进行结构设计、工艺改进和特性分析.     

平面型InGaAs探测结构中p型杂质的二维扩散行为研究

在平面型InGaAs P-i-N短波红外探测结构中,p型杂质在材料中纵向和横向的扩散是决定pn结位置及其光电性能的主要因素,本文采用扫描电容显微方法(SCM)获得了扩散成结InGaAs/InAlAs像元剖面的二维载流子分布,从而实现对不同扩散条件下pn电场结的精确定位和分析.此外,对于InGaAs/InP探测器,SCM...     

CdSe核辐射探测器的噪声与漏电流

对具有金属-半导体-金属(MSM)结构的CdSe探测器的噪声进行了实验观测,并对探测器中光生载流子的输运过程进行了分析,结果表明探测器的噪声是由从正极注入的空穴电流引起的.因此只有改变正极接触,才能有效地阻止空穴注入,从而消除探测器噪声.     

A device model for metal-semiconductor-metal photodetectors and itsapplications to optoelectronic integrated circuit simulation

Poisson's equation, current-continuity equations, and a rate equation for charged traps are numerically solved in two dimensions, to explain the behavior of photogenerated carriers and electric fields in GaAs metal-semiconductor-metal photoconductors (MSM PDs). An analytical model is proposed on the basis of these solutions and implemented in a SPICE-like circuit simulator. Simulated transient responses for an MSM PD and a monolithic optoelectronic receiver, consisting of an MSM PD and a MESFET transimpedance amplifier, are in good agreement with measured results     

同心导体圆盘-圆环结构散射场的一种分析方法

本文从电场积分方程出发,经傅氏变换,并分离出电荷对散射场的贡献,导出了平面波投射于同心圆盘-圆环结构时,分析散射场的一个形式简单且便于求解的积分方程。当平面波正投射时解法尤为简单。据此求解圆盘和/或圆环结构上感应电流分布和相应的散射场。为验证本方法的准确性,对圆盘雷达散射截面(RCS)的计算结果与精确解进行了比较,结果吻合很好。文中还给出了当平面波正投射时,同心圆盘-圆环结构上感应电流各分量的幅度分布和散射场分布。     

Effect of electromagnetic radiation on an array of weakly interacting carbon nanotubes in the presence of nanosecond pulses

For metallic “zigzag”-type carbon nanotubes, the dependence of a nonlinear current on an ac electric field with an inclined-leading-edge width of ΔT = 3 × 10^?11 s and wavelength of λ ≈ 1 mm is studied. It is theoretically and numerically shown that the surface current is almost independent of the nanotube radius. In the case of semiconductor zigzag-type nanotubes, the radiation of a two-frequency CO₂ laser with a constant amplitude is considered as an ac electric field. The dependence on the relaxation time in the Boltzmann kinetic equation is studied. The optimal conditions for terahertz-radiation generation are achieved when the relaxation time is 40 fs. It is numerically found that the amplified radiation amplitude behaves as beats.     

Tunneling-assisted IMPATT operation

The influence of tunneling on the efficiency of millimeter-wave IMPATT diodes is investigated. For a reliable estimation of this influence, the tunnel generation rate coefficients are measured from silicon p-i-n diodes. The Read equation is solved taking a time-dependent tunnel current into account. The phase distortion, which is responsible for the efficiency degradation caused by tunneling, is calculated analytically and numerically. It is shown that for an exact solution the injected current density should be calculated numerically. The results suggest that for efficient silicon IMPATT diode operation, the maximum electric field should be below 1×10⁶ V/cm. Due to the current and field dependent representation of the injection phase, there are direct consequences on the design of millimeter- and submillimeter-wave transit time diodes for high power generation as well as for low-noise operation     

NEW APPROACH TO ELECTROMAGNETIC SCATTERING FROM A CONDUCTIVE DISC-RING STRUCTURE

A one-dimensional modified integral equation for electromagnetic scattering from a metallic concentric disc-ring structure is derived by using Fourier expansion and separating the contribution of charge density from conventional EFIE. In the case of normal incidence, the derived equation is very simple and easy to be solved numerically regardless of the electric dimension of the structure. The comparison between the data of RCS of a disc by using this method and analytical method shows the effectiveness of this approach. Numerical results are also given for current distributions and the scattered fields for a disc-ring structure.     

Determination of lines of constant phase in the near-field of ametallic cube and an airplane

A method is presented which enables one to calculate the scattered field very close to the surface of a perfectly conducting body as well as at the surface itself. The method is based on the representation of the scattered field by an integral over the surface current distribution. The integrand is treated by identity transformations that the singular terms can be integrated analytically, while the remaining nonsingular terms are integrated numerically. The surface current distribution is determined by the magnetic field integral equation. The theory is validated by experiments with the scattered field of a metallic cube with an edge length of a wavelength. The current distribution and the normal as well as the tangential electric field at the surface of the cube are measured by small probes, and the results are compared to those of the theory. The theoretical results of the current distributions are presented as gray value graphics-those of the near-field distribution of a cube and an airplane with the help of lines of constant phase     

Domain integral equation analysis of integrated optical channel andridge waveguides in stratified media

A domain integral equation approach to computing both the propagation constants and the corresponding electromagnetic field distributions of guided waves in an integrated optical waveguide is discussed. The waveguide is embedded in a stratified medium. The refractive index of the waveguide may be graded, but the refractive indices of the layers of the stratified medium are assumed to be piecewise homogeneous. The waveguide is regarded as a perturbation of its embedding, so the electric field strength can be expressed in terms of domain integral representation. The kernel of this integral consists of a dyadic Green's function, which is constructed using an operator approach. By investigating the electric field strength within the waveguide, it is possible to derive an integral equation that represents an eigenvalue problem that is solved numerically by applying the method of moments. The application of the domain integral equation approach in combination with a numerically stable evaluation of the Green's kernel functions provides a new and valuable tool for the characterization of integrated optical waveguides embedded in stratified media. Numerical results for various channel and ridge waveguides are presented and are compared with those of other methods where possible     

Comparison of Lorentz and Coulomb gauge formulations fortransverse-electric wave scattering by two-dimensional surfaces ofarbitrary shape in the presence of a circular cylinder

Two forms of the so-called mixed-potential electric field integral equation (MPIE) are developed for two-dimensional perfectly conducting (PC) surfaces of arbitrary shape in the presence of an infinite PC cylinder of circular cross section subject to transverse-electric (TE) excitation. One of the MPIEs is based on the Coulomb gauge; the other uses the Lorentz gauge. In either case, the effect of the cylinder is incorporated in the integral equation by means of the appropriate Green's functions, leaving the current distribution on the arbitrary surface as the only unknown. The Green's functions are derived by the eigenfunction expansion technique. An existing well-established moment method procedure is adapted to solve both forms of the MPIE numerically. Computed results are presented for several cases of interest, and the relative merits of the Coulomb and Lorentz gauge MPIEs are discussed     

Numerical evaluation of complex resonances of an elliptic cylinder

Complex natural resonances of an elliptic cylinder are determined numerically by contour integration of the determinant of the moment matrix obtained in a homogeneous solution of the electric field integral equation (EFIE). These resonances compare well with asymptotic estimates derived from radial eigenfunction expansion for scattering from cylinders.     

A numerical implementation of a modified form of the electric field Integral equation

The details of a Galerkin discretization scheme for a modified form of the electric field integral equation are outlined for smooth, three-dimensional, perfectly conducting scatterers. Limitations of the divergence conforming finite-element bases in preserving the self-stabilizing properties of the electric field integral equation operator are indicated. A numerically efficient alternative is outlined which relies on an operator-based Helmholtz decomposition. The condition number of the resulting matrix equation is demonstrated to be frequency independent for scattering from a perfectly conducting sphere at various frequencies.