Summary

电浆光电导太赫兹发射器的设计,制造和实验表征

Published: July 08, 2013
doi:

Summary

我们描述电浆光电发射器,它提供了两个数量级更高的太赫兹功率水平相比传统的光电发射器的设计,制造,实验表征方法。

Abstract

在这个视频文章中,我们提出了一个详细的演示了一种高效的方法产生太赫兹波。我们的技术的基础上,这一直是光电导开关产生太赫兹波1-8的最常用的技术之一。开关产生太赫兹波的光导发射器是通过用脉冲或外差激光照明抽超快光电导体。引起的光电流,如下泵浦激光器的包络线,被路由到连接到光电导体的接触电极,以产生太赫兹辐射的太赫兹辐射天线。的光导发射器的量子效率虽然理论上可以达到100%时,相对长的光生载流子的输送路径的长度,以传统的感光鼓接触的电极的严重限制了它们的量子效率。此外,严格限制的载流子屏蔽效应和热击穿的最大输出P奥尔传统的光电导太赫兹光源。为了解决传统的光导太赫兹发射器的量子效率的限制,我们已经开发出一种新的光电发射器的概念,它采用了等离子体接触电极配置,同时提供高量子效率和超快操作。通过使用纳米尺度的表面等离子体激元的接触电极,显着地降低平均光生载流子传输路径与感光鼓接触的电极相比,传统的感光鼓9。我们的方法也可以增加感光面积不大量增加的容性负载天线活跃,拉动了最大的太赫兹辐射的功率防止高光泵权力载体筛选效应和热击穿。通过将等离子体接触电极,我们证明提高光 – 太赫兹的电源转换效率的传统的光电TErahertz发射器50 10的一个因素。

Introduction

我们提出了一个新颖的光电导太赫兹采用了表面等离子体激元的接触电极配置的发射器,其由两个数量级,以提高转换效率的光 – 太赫兹。我们的技术解决了最重要的局限性,传统的光导太赫兹发射器,即输出功率和低功率效率不佳,这源于固有的高量子效率和超快操作常规感光鼓之间的权衡。

在我们的设计中,导致此越级性能改进的关键新奇设计的接触电极配置,积累了大量的光生载流子在靠近接触电极,使得它们可以被收集于一个子皮秒时间尺度。换句话说,感光鼓的超快的操作和高的量子效率之间的权衡是缓解了空间操纵光属TED运营。电浆接触电极提供这种独特的能力(1)允许光限制到电浆电极(超越衍射极限),(2)非寻常光增强在金属接触和光吸收半导体界面10,11纳米器件之间的活跃的地区。我们的解决方案的另一个重要属性是它可容纳大感光活跃的领域太赫兹辐射天线寄生负载不大量增加。利用大的感光体有源区启用减轻载流子屏蔽效应和热击穿,这是最终从传统的光导发射器的最大发射功率的限制。此视频文章都集中在我们提出的解决方案的独特属性描述理事物理,数值模拟和实验验证。我们的实验证明高出50倍太赫兹权力从电浆辐透在一个类似的比较,与非等离激元的接触电极的光导发射器的发射极oconductive。

Protocol

1。电浆光电发射器制造制造电浆光栅。 清洁半导体晶片浸渍在丙酮中(2分钟),然后用异丙醇(2分钟),并用去离子水漂洗(10秒)。 用氮气干燥样品,在加热板上加热在115℃下进行90秒,以去除任何剩余的水。 自旋950K PMMA微化A4在样品上,在4,000 rpm的转速下持续45秒。预烘3分钟,在180℃的加热板上对抗蚀剂。 将样品放入电子束光刻工具(JEOL JBX-6300-FS)。等?…

Representative Results

为了证明电浆电极太赫兹功率增强的潜力,我们两个太赫兹发射器:传统( 图1a)和电浆( 图1b)光电发射器将电浆降低载流子输运次接触电极的接触电极。这两种设计包括超快的感光鼓与20微米之间的间隙的阳极和阴极接触,与最大和最小宽度分别为100微米和30微米,60微米长的领结天线连接到相同的LT-GaAs衬底上制作的。电浆光电发射器集成了两个纳米电浆接触光栅成?…

Discussion

在这个视频文章中,我们提出了一种新型的光电导开关产生太赫兹波的技术,它使用一电浆接触电极配置,以提高光到太赫兹波的转换效率提高两个数量级。提出电浆光导发射的太赫兹辐射的功率显着增加,为未来的高灵​​敏度的太赫兹成像光谱仪和分析系统,用于先进的化学识别,医学成像,生物传感,天文学,大气遥感,安检,是非常有价值的材料特性。

这个视频文?…

Disclosures

The authors have nothing to disclose.

Acknowledgements

笔者想感谢Picometrix提供LT-GaAs衬底,并衷心感谢密歇根空间格兰特联盟的财政支持,DARPA的青年教师奖由约翰·阿尔布雷希特博士(合同编号N66001-10-1-4027),美国国家科学基金会职业管理管理萨米尔·El-Ghazaly的博士(合同编号N00014-11-1-0096),ONR青年研究者奖管理博士保罗希(合同编号N00014-12-1-0947),和ARO青年研究者奖管理奖开发帕尔默博士(合同#W911NF-12-1-0253)。

Materials

      Reagent
Polymethyl Methacrylate (PMMA) MicroChem 950K PMMA A4  
Hexamethyldisilazane (HMDS) Shin-Etsu MicroSI MicroPrime HP Primer  
Optical Photoresist Dow Chemical Megaposit SPR 220-3.0  
Photoresist Developer AZ Electronic Materials AZ 300 MIF Developer  
Methyl Iso-Butyl Keytone (MIBK) Avantor Performance Materials 9322-03  
      Equipment
Ti:Sapphire Mode-Locked Laser Coherent MIRA 900D V10 XW OPT 110V  
Pyroelectric Detector Spectrum Detector SPI-A-65 THz  
Electron-Beam Lithography Tool JEOL JBX-6300-FS  
Plasma Stripper Yield Engineering Systems YES-CV200RFS  
Metal Evaporator Denton Vacuum SJ-20  
Plasma Enhanced Chemical Vapor Deposition Tool GSI GSI PECVD System  
Projection Lithography Stepper GCA AutoStep 200  
Reactive Ion Etcher LAM Research 9400  
Parameter Analyzer Hewlett Packard 4155A  
Optical Chopper Thorlabs MC2000  
Lock-in Amplifier Stanford Research Systems SR830  
Electrooptic Modulator Thorlabs EO-AM-NR-C2  
Motorized Linear Stage Thorlabs NRT100  

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Cite This Article
Berry, C., Hashemi, M. R., Unlu, M., Jarrahi, M. Design, Fabrication, and Experimental Characterization of Plasmonic Photoconductive Terahertz Emitters. J. Vis. Exp. (77), e50517, doi:10.3791/50517 (2013).

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