肖特基势垒二极管

肖特基势垒二极管是针对开关电源、开关稳压器等输出端低压、高频、大电流的高效率整流应用     

SiC气体传感器

SiC肖特基二极管气体传感器可以广泛应用于检测气体排放物和气体泄露。通过采用PdCr合金 ,可以提高Pd/SiC气体传感器的灵敏度。同时 ,在Pd层和SiC之间引入SnO2 作为界面层也是提高其灵敏度的一种有效途径。进一步的研究表明 ,SnO2 层的大小也对传感器的性能有着重要影响。     

肖特基二极管金属质量问题研究

介绍了出现在肖特基二极管金属膜上常见的几种异常情况,其中包括金属迸溅、金属“毛刺”以及金属DIC模式鼓泡现象.经过对不同问题的深入探究,分析出了各种现象产生的具体原因,并结合我所实际情况给出了有效的解决措施.     

肖特基二极管检波器在标量网络分析仪中的应用

分析了低势垒肖特基二极管（ＬＢＳＤ）的检波特性和温度特性，介绍了标量网络分析仪（ＳＮＡ）的特点，描述了检波器非线性修正系统和温度补偿电路的设计 。     

光纤氢气敏传感器的实验研究

本文介绍一种运用光纤干涉仪及其准外差检测系统对氢气分压强的检测方法。在光纤Mach-Zehnder干涉仪的传感臂上粘接一段长为3cm、厚为100μm的钯片,形成传感元。实验可检测到5×10~2Pa的氢气分压强。     

氢气传感器的研究进展

作为氢气检测的一种重要手段,氢气传感器显得尤为重要。介绍了目前研究最为广泛的半导体型、热电型、光纤型3种氢气传感器的研究进展,分别阐述了这3种传感器的结构、工作原理、研究现状及其优缺点,并对氢气传感器的应用前景和研究方向进行了展望。     

一种基于电子隧穿机制的柔性氢气传感器

氢气传感器在涉氢安全领域扮演着重要角色,随着可穿戴设备大量应用,柔性氢气传感器的发展日益受到重视。纳米粒子薄膜以其离散的纳米颗粒状结构和独特的电学响应性质成为了理想的柔性氢气敏感材料。通过在聚对苯二甲酸乙二醇酯(PET)柔性衬底上沉积钯(Pd)纳米粒子薄膜构筑了一种柔性氢气传感器。通过上百次反复弯折,该传感器体现了较好的机械性能和电学稳定性,气敏性能在弯折循环前后无衰减。通过系统研究应变状态下的氢气响应性质,发现拉应变使Pd纳米粒子薄膜的氢气响应度增大,而压应变效应则相反。其原因主要归结为应变导致的纳米颗粒间距变化,拉应变产生的较大的纳米颗粒间距会使得传感器电流基线降低,且足够大的纳米粒子间距更能容纳Pd纳米粒子吸氢导致的晶格膨胀,反之亦然。此外,拉应变使Pd纳米粒子薄膜对氢气的响应时间显著缩短,而压应变产生的效果则相反。该氢气传感器探测范围达到0~10%,响应时间可达数秒量级,探测下限为25×10^-6。在低氢气浓度范围内,响应度ΔI/I0与P1/2H2呈现线性关系,对4%浓度氢气的响应度可达600%,灵敏度可达3.28% Pa-1/2。这些结果表明,该传感器具备优异的传感性能,在柔性气体传感器领域具有极大应用潜力。     

钴掺杂二氧化锡基氢气传感器气敏特性研究

氢气(H2)是溶解在变压器油中的重要故障特征气体,对油中溶解的H2气体浓度进行在线监测能实时有效反映变压器的运行状况.针对传统的二氧化锡基气体传感器检测油中溶解气体存在工作温度较高,气体响应较低的问题,提出一种用金属钴Co掺杂纳米二氧化锡SnO2基传感器检测变压器油中溶解气体的方法,介绍其制备方法研制气体传感器并测试H2气敏特性,同时基于第一性原理对其敏感机理进行了探讨.结果表明:金属Co掺杂SnO2后传感器的最佳工作温度降低至300℃,对50μL/L H2的灵敏度增到12.16,Co掺杂后SnO2的导带负移,在费米能级附近出现了新的掺杂能级,增大了SnO2表面的导电性能,H2吸附在Co-SnO2表面时,价带顶附近区域出现了新的表面态,有利于载流子在价带和导带间的转移,从而改善传感器的气敏性能.     

耐高压FBG压力传感器实验研究

为了提高光纤Bragg光栅（FBG）的压力灵敏度以实现油气井下高压传感的测量要求,设计了一种以薄壁筒为衬底外加保护套的耐高压FBG传感器。将FBG沿着弹性筒的轴向用高温胶固化在筒的内部。由于外界油压将引起弹性筒轴向压缩并传递到FBG上引起FBG波长的变化,测量FBG波长的变化即可得到外界压力的变化。理论得到传感器的压力响应灵敏度为-0．035nm／MPa;0-40MPa压力范围内压力实验测得传感器压力响应灵敏度为-0．0339nm／MPa,线性拟合度为0．9997,理论和实验符合得很好。结果表明：该传感器性能稳定,线性度和重复性好,可以用于油气井下高压的实时测量。     

Minority-carrier MIS tunnel diode hydrogen sensors

The electrical characteristics of Pd/LB film/n-Si tunnel diode hydrogen sensors containing one and three cadmium stearate Langmuir-Blodgett (LB) films are reported. The devices exhibit good rectification behaviour. However, the IV characteristics are complex and deviate considerably from ideal Schottky-barrier theory. The semiconductor surface appears to be inverted at zero bias. Saturation of the forward current is attributed to tunnel-limited transport in the case of single LB film devices and to insulator-limited conduction in the case of devices containing three LB films. Exposure to hydrogen causes pronounced degradation of the diode behaviour. In particular, the forward IV characteristics shows an IV² behaviour that cannot be satisfactorily explained. A plausible explanation, however, is offered for much of the observed data based upon a minority-carrier metal-insulator-semiconductor (MIS) tunnel diode model. However, the full range of behaviour observed cannot be treated adequately by any one theoretical model.     

Ammonia sensing characteristics of a Pt/AlGaN/GaN Schottky diode

The interesting ammonia sensing current-voltage (I-V) characteristics of a Pt/AlGaN/GaN Schottky diode are firstly studied and demonstrated. It is found that the ammonia sensitivity is increased by increasing the temperature. Yet, the sensitivity is decreased when the temperature is higher than 423 K. Experimentally, the studied device exhibits a good sensitivity of 13.1 under exposing to a relatively low concentration ammonia gas of 35 ppm NH₃/air. In addition, the good sensing performance of the studied device is demonstrated over a wide operating temperature regime from 298 K to 473 K. A highest ammonia sensing response of 182.7 is found at 423 K while a 10,000 ppm NH₃/air gas is introduced.     

SAW氢传感器的研究进展

对声表面波(SAW)氢传感器的研究目前主要集中在改善其敏感性、加快响应速度、增强稳定性以及消除温度的影响。要实现这些目标,一是改善SAW氢传感器的关键部件——敏感薄膜的性能;二是改进传感器的结构。对主要研究机构在这些方面的研究进行了系统的综述,并提出了发展方向。     

Pd/porous-GaAs Schottky contact for hydrogen sensing application

The potential of Pd/porous-GaAs Schottky contacts for hydrogen detection at room temperature is presented. The Pd/porous-GaAs contacts were developed using an electrochemical system in our laboratory. Using both forward- and reverse current–voltage (I–V) characteristics we have found that the Pd/porous-GaAs Schottky diode sensor exhibited very high sensitivity towards hydrogen gas. The Pd/porous-GaAs diode sensor submitted to 500 ppm hydrogen gas at room temperature revealed a considerable increase in sensitivity of more than three times higher than that of the Pd/GaAs sample. The significant changes observed here have been found to be due to the results of a decrease in effective barrier height of the Schottky contact. This is due to a lowering of metal work function and eventually the creation of a dipole layer on the semiconductor surface induced by dissociation of hydrogen atoms on the Pd contact, followed by diffusion to the Pd/porous-GaAs interface. A comparative study has been conducted to show the differences between Pd/GaAs and the Pd/porous-GaAs Schottky contacts fabricated at different conditions and subjected to hydrogen gas at various operating temperatures. Scanning electron microscopy (SEM) was used to examine the porosity of the GaAs surfaces. SEM pictures showed highly porous structures of the Pd/porous-GaAs Schottky contacts provided for penetration of hydrogen gas molecules.     

电容式土壤水分传感器的电导变异性试验研究

为评估电容式土壤水分传感器受土壤电导率的影响及其对农田土壤电导率变化范围的适用性,配制了一系列土壤等效含水率为40.6%、电导率为0~1.91dS/m的土壤等效介电溶液,分别对激励信号频率为40,50,60,70,80,90,100MHz的7种传感器进行了电导变异性试验,并且配制了相同含水率但电导率分别为0,0.31,0.46和0.61dS/m的4种土样进行了验证试验。试验结果表明:1)土样中的测试结果基本上与介电溶液吻合,可采用等效介电溶液评估传感器的电导变异性;2)传感器的电导变异率随待测介质电导率的升高而近似线性增大,相同电导率下,传感器激励信号频率越高其电导变异率越小;3)在农田土壤电导率基本变化区域0.239~0.650 dS/m内,当传感器激励信号频率从不低于80MHz时,其最大电导变异率为9.2%,能满足工程上的实际应用要求。     

氢渗透传感器的安全设计

石化行业使用氢渗透传感器监测设备的安全运行,评估设备的安全运行状态.通过分析氢渗透传感器工作原理,深入探讨了影响氢渗透传感器的环境因素,分析了传感器的技术要求.分析表明:氢渗透传感器的防爆性能要符合ExiaⅡAT4,采用聚四氟乙烯作为传感器的内腔保护层,正确使用氢渗透传感器延长使用寿命,氢渗透传感器的安全设计具有实践指导意义.     

氢传感器的研究进展

氢气广泛地应用于航天和其他工业中,但其极易泄露、易燃、易爆,因此,对于氢传感器的研究显得十分迫切。综述了复合稀土氟化物氢传感器、半导体氧化物氢传感器、表面等离子钯膜氢传感器的国内外研究进展情况,着重对半导体氧化物氢传感器的原理、结构、性能以及取得的研究成果进行了介绍,并提出了氢传感器的发展方向和前景。     

A design of 210 to 235 GHz fixed tuned mixer using planar Schottky diode

This paper presents the design of a fixed tuned 210 to 235 GHz subharmonic mixer (SHM). The mixer is designed using GaAs based planar antiparallel Schottky diode pair AP1/G2/0P95 from Rutherford Appleton Laboratory. 3D model of the Schottky diode is discussed and simulated to consider parasitic effects of the diode. Detailed design technique of each of its subsections as well as the integrated mixer circuit is presented. Nonlinear co‐simulation of the designed mixer exhibits double sideband (DSB) conversion loss less than 9.2 dB over the frequency band 210 to 235 GHz with 4 dBm of local oscillator (LO) power while the area of the rectangular printed section is 4.224 × 0.35 mm.