Analysis of nano-grating-assisted light absorption enhancement in metal-semiconductor-metal photodetectors patterned using focused ion-beam lithography

We present finite-difference time-domain (FDTD) analysis results of light absorption enhancement factor dependence on the profile shape of nano-gratings etched into the surfaces of metal-semiconductor-metal photodetector (MSM-PD) structures. The MSM-PDs patterned by nano-gratings are optimized geometrically, improving the light absorption near the design wavelength through plasmon-assisted electric field concentration effects. FDTD simulation results show about 50 times light absorption enhancement prediction for 850 nm light due to improved optical signal propagation through the nano-gratings in comparison with the conventional MSM-PD designs employing only a subwavelength aperture. We also report on the nano-grating profile shapes obtained typically in our experiments using focused ion-beam lithography and discuss the dependency of light absorption enhancement on the geometric parameters of nano-gratings inscribed into MSM-PDs.     

MSM激光距离成像雷达系统设计与实验研究

阐述MSM激光距离成像雷达测距成像基本原理,设计并搭建了构成雷达系统核心的调频信号发生器、调幅激光发射器及MSM自混频探测电路,选取MSM探测器上某成像单元进行雷达测距性能及距离分辨率实验,验证了线性调频带宽约400 MHz时距离分辨率0.375 m的设计指标,为雷达样机下一步实现距离成像奠定了技术基础.     

GaN基MSM结构光伏型紫外探测器建模及其仿真分析

Based on the principles of metal-semiconductor-metal Schottky barrier photodetectors(MSM-PD), using the carrier rate equations,the circuit simulation model of a GaN-based MSM photovoltaic ultraviolet detector is constructed through an appropriately equivalent process.By using the Pspice analytical function of Cadence soft on the model,the relationship between the photocurrent and the terminal voltage under different UV light powers is analyzed.The result shows that under the given UV power,the photocurre...     

Simulation of the Metal-Semiconductor-Metal photodetector based on InGaAs for the photodetection at the wavelength 1.55 μm

In this paper we present the simulation of Metal-Semiconductor-Metal photodetector (MSM-PD) of interdigitated planar structure based on InAlAs/InGaAs adapted for photodetection at the wavelength 1.55 μm. We use the theoretical models to plot the variations of the dark current, the photocurrent, the capacity, and the cut-off frequency of the photodetector as a function of bias voltage and the interelectrode distance. The obtained results show a very low dark current, mainly due to the introduction of a thin layer to increase the Schottky barrier based on In_0.52Al_0.48As in the epitaxial structure of component. The obtained photocurrent and cut-off frequencies are very appreciable, these latter are mainly limited by the transit time of the photo-generated carriers given the low component capacity obtained by simulation.     

Low dark current and internal gain mechanism of GaN MSM photodetectors fabricated on bulk GaN substrate

Metal-semiconductor-metal ultraviolet photodetectors are fabricated on low-defect-density homoepitaxial GaN layer on bulk GaN substrate. The dislocation density of the homoepitaxial layer characterized by cathodoluminescence mapping technique is ∼5 × 10⁶ cm⁻². The photodetector with a high UV-to-visible rejection ratio of up to 1 × 10⁵ exhibits a low dark current of <2 pA at room temperature under 10 V bias. The photo-responsivity of the photodetector gradually increases as a function of applied bias, resulting in a photodetector quantum efficiency exceeding 100% at above medium bias. The photo-responsivity also shows a dependence on the incident optical power density and illumination conditions. The internal gain mechanism of the photodetector is attributed to photo-generated holes trapped at the semiconductor/metal interface as well as high-field-induced image-force lowering effect.     

不同钝化结构对非极性AlGaN-MSM紫外探测器性能的提升

在r面蓝宝石衬底上,采用金属有机化学气相沉积（MOCVD）法高温生长了未掺杂非极性AlGaN半导体薄膜,在此基础上制备了金属-半导体-金属（MSM）结构的紫外探测器。系统研究了在AlGaN半导体薄膜表面分别磁控溅射SiO₂纳米颗粒与SiO₂钝化层两种钝化手段对非极性AlGaN-MSM结构的紫外探测器性能的影响。实验结果表明：磁控溅射SiO₂纳米颗粒钝化或SiO₂钝化层两种手段都能提升AlGaN-MSM结构紫外探测器性能。暗电流测试表明,SiO₂纳米颗粒和SiO₂钝化层可使器件暗电流下降1~2个数量级,达到nA量级。光谱响应测试发现,在5 V偏压下,探测器在300 nm处具有陡峭的截止边,这表明其具有很好的深紫外特性,光谱响应提高了10³倍,紫外可见抑制比高达10⁵。     

MSM型Clos交换结构及算法的OPNET建模与仿真

交换结构是交换机的核心,决定着交换机的性能。MSM型Clos交换结构是一种高性能交换结构,为有效仿真分析该交换结构建立了一种OPNET仿真模型。该模型将交换系统抽象为一个星型网络,其边缘节点对应交换结构输入和输出,中心节点对应MSM型Clos交换结构;并使用此模型仿真分析了3种典型算法的性能。该模型为交换结构性能的仿真分析提供了一种有效途径。     

基于MODEM实现的远距离多机主从式通信技术

概述了MSM7512BRS在远距离多机主从式通信中的应用,详细介绍了该器件的引脚功能和工作方式,给出了在实际工程应用中由计算机和单片机组成的通信系统的工作原理,并对其工作过程进行分析.     

MSM光探测器瞬态特性的二维分析及优化设计

应用有限差分方法对金属-半导体-金属光探测器进行二维分析,全部数值模拟工作都是基于半导体物理的基本微分方程完成的.结合模拟结果对金属-半导体-金属光探测器的瞬态响应进行了分析,以特性分析结果为基础针对探测器的响应速度和响应率等性能指标进行了二维结构上的优化设计.