基于石墨烯器件的太赫兹应用
发布时间：2021-06-17 03:53
自太赫兹辐第一次被发现后,太赫兹辐射对于研究物质和基于太赫兹辐射的新兴应用的一直吸引着人们的目光。例如安检领域、医学成像以及光谱学研究。然而遗憾的是,太赫兹光谱范围仍然是被利用最少的光谱区域之一,其主要原因是缺少紧凑经济适用并且可以在室温下稳定工作的太赫兹源,太赫兹放大器以及太赫兹被动器件。本论文主要涉及两个基于石墨烯材料的先进太赫兹器件的研究。在一个器件主要研究了在电中性的石墨烯-六角氮化硼范德华器件中的石墨烯,通过连续中红外激光击发后的载流子寿命。通过对于中红外光照射后的石墨烯器件中光电导的测量,在低能量密度以及低偏压的条件下,在带间库伦散射作用下,石墨烯中的热载流子寿命可达几十皮秒。而在带间库伦散射与外加电场或光场控制的双曲型声子-极化子散射的共同作用下,可以将热载流子时间控制在几十至几个皮秒之间。该项目通过利用石墨烯/六角氮化硼异质结构,实现高灵敏太赫兹光探测器以及声子极化子光学,为太赫兹激光器的发展开辟了有趣的前景。另一个是基于石墨烯的太赫兹光电控调制器件,我们提出了一种容易制备的金属-半导体-石墨烯长方型波导结构。这是一种容易制造的器件,可充当太赫兹振幅调制器和太赫兹放大器...
【文章来源】：华东师范大学上海市 211工程院校 985工程院校 教育部直属院校
【文章页数】：155 页
【学位级别】：博士
【文章目录】：
摘要
ABSTRACT
Chapter 1 Introduction
1.1 General context
1.2 STATE-OF-THE-ART
1.2.1 THz sources
1.2.2 THz amplifiers
1.2.3 THz amplitude modulators
1.2.4 THz waveguides
1.3 Graphene for THz technology
1.3.1 Electronic band structure of graphene
1.4 Thesis outline
Chapter 2 Graphene/hBN phototransistors:transport properties
2.1 Introduction
2.2 Fabrication of the graphene/h BN phototransistors
2.3 Experimental set-up for transport measurements
2.4 The current properties in biased graphene
2.5 Dark current-bias characteristics of the graphene/hBN phototransistors
2.6 Conclusion
Chapter 3 Photoresponse of graphene-hBN phototransistors under mid-infrared illumination
3.1 Photo-transport in biased graphene/h BN phototransistor
3.1.1 Experimental set-up
3.1.2 Spatial profile of the photocurrent
3.1.3 Competing mechanisms for photocurrent
3.2 Linear photoresponse in biased graphene/hBN phototransistor
3.2.1 Photocurrent–bias characteristics
3.2.2 Photoexcited carrier density
3.2.3 Carrier lifetime
3.2.4 Responsivity
3.2.5 Influence of light polarization
3.3 Nonlinear photoresponses in biased graphene/hBN phototransistor
3.3.1 Non-linear regime in V_(DS)~*
3.3.2 Emission of Hyperbolic Phonon Polaritons
3.3.3 Non-linear regime in Pinc
3.3.4 Photoexcited carrier density
3.3.5 Full photoconductive response including all regimes
3.4 Conclusion and Perspectives
Chapter 4 Graphene based metal-dielectric waveguide
4.1 Introduction
4.2 Description of the graphene-coupled dielectric-metal waveguides
4.3 Mode analysis of waveguides based on FEM method
4.3.1 Full vector mode analysis in 2D
4.3.2 Boundary conditions
4.3.3 Dispersion relation of the fundamental modes
4.3.4 Graphene coupled to the hybrid dielectric-metal waveguide
4.4 Conclusion
Chapter 5 THz characterization of the graphene coupled hybrid waveguides
5.1 Fabrication and process characterization
5.1.1 Characterization of the graphene coverage
5.1.2 Electrical characterization
5.2 THz characterization of the devices
5.2.1 THz time-domain spectroscopy system
5.2.2 THz characterization of the hybrid waveguides
5.2.3 Interpretation based on interference effect
5.3 Conclusion and perspectives
Chapter 6 General conclusion and perspectives
Appendix A Appendix
Appendix B Fabrication of waveguide samples
B.1 The strategy uesd in mapping Raman spectroscopy
Bibliography
作者简历
科研成果
后记
本文编号：3234410
【文章来源】：华东师范大学上海市 211工程院校 985工程院校 教育部直属院校
【文章页数】：155 页
【学位级别】：博士
【文章目录】：
摘要
ABSTRACT
Chapter 1 Introduction
1.1 General context
1.2 STATE-OF-THE-ART
1.2.1 THz sources
1.2.2 THz amplifiers
1.2.3 THz amplitude modulators
1.2.4 THz waveguides
1.3 Graphene for THz technology
1.3.1 Electronic band structure of graphene
1.4 Thesis outline
Chapter 2 Graphene/hBN phototransistors:transport properties
2.1 Introduction
2.2 Fabrication of the graphene/h BN phototransistors
2.3 Experimental set-up for transport measurements
2.4 The current properties in biased graphene
2.5 Dark current-bias characteristics of the graphene/hBN phototransistors
2.6 Conclusion
Chapter 3 Photoresponse of graphene-hBN phototransistors under mid-infrared illumination
3.1 Photo-transport in biased graphene/h BN phototransistor
3.1.1 Experimental set-up
3.1.2 Spatial profile of the photocurrent
3.1.3 Competing mechanisms for photocurrent
3.2 Linear photoresponse in biased graphene/hBN phototransistor
3.2.1 Photocurrent–bias characteristics
3.2.2 Photoexcited carrier density
3.2.3 Carrier lifetime
3.2.4 Responsivity
3.2.5 Influence of light polarization
3.3 Nonlinear photoresponses in biased graphene/hBN phototransistor
3.3.1 Non-linear regime in V_(DS)~*
3.3.2 Emission of Hyperbolic Phonon Polaritons
3.3.3 Non-linear regime in Pinc
3.3.4 Photoexcited carrier density
3.3.5 Full photoconductive response including all regimes
3.4 Conclusion and Perspectives
Chapter 4 Graphene based metal-dielectric waveguide
4.1 Introduction
4.2 Description of the graphene-coupled dielectric-metal waveguides
4.3 Mode analysis of waveguides based on FEM method
4.3.1 Full vector mode analysis in 2D
4.3.2 Boundary conditions
4.3.3 Dispersion relation of the fundamental modes
4.3.4 Graphene coupled to the hybrid dielectric-metal waveguide
4.4 Conclusion
Chapter 5 THz characterization of the graphene coupled hybrid waveguides
5.1 Fabrication and process characterization
5.1.1 Characterization of the graphene coverage
5.1.2 Electrical characterization
5.2 THz characterization of the devices
5.2.1 THz time-domain spectroscopy system
5.2.2 THz characterization of the hybrid waveguides
5.2.3 Interpretation based on interference effect
5.3 Conclusion and perspectives
Chapter 6 General conclusion and perspectives
Appendix A Appendix
Appendix B Fabrication of waveguide samples
B.1 The strategy uesd in mapping Raman spectroscopy
Bibliography
作者简历
科研成果
后记
本文编号：3234410
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