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Enhancement of Light Matter Interaction of Thin Film Materials in Optoelectronic Devices: Plasmonic Antennas, Electro-Optic Modulators, and Solar Cells

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Enhancement of Light Matter Interaction of Thin Film Materials in Optoelectronic Devices: Plasmonic Antennas, Electro-Optic Modulators, and Solar Cells Enhancement of Light Matter Interaction of Thin Film Materials in Optoelectronic Devices: Plasmonic Antennas, Electro-Optic Modulators, and Solar Cells by Mohammadhossein Tahersima B.S. in Electronics System Engineering, April 2012, Kyoto Institute of Technology A Dissertation submitted to The Faculty of The School of Engineering and Applied Science of the George Washington University in partial fulfillment of the requirements for the degree of Doctor of Philosophy August 31, 2018 Dissertation directed by Volker J. Sorger Associate Professor of Electrical and Computer Engineering The School of Engineering and Applied Science of The George Washington University certifies that Mohammadhossein Tahersima has passed the Final Examination for the degree of Doctor of Philosophy as of April 30, 2018. This is the final and approved form of the dissertation. Enhancement of Light Matter Interaction of Thin Film Materials in Optoelectronic Devices: Plasmonic Antennas, Electro-Optic Modulators, and Solar Cells Mohammadhossein Tahersima Dissertation Research Committee: Volker J. Sorger, Associate Professor of Electrical and Computer Engineering, Dissertation Director Can Korman, Professor of Electrical and Computer Engineering, Committee Member Mona Zaghloul, Professor of Electrical and Computer Engineering, Committee Member Shahrokh Ahmadi, Professor of Electrical and Computer Engineering, Committee Member Anastas Popratiloff, Director, Center for Microscopy and Image Analysis, Committee Member ii © Copyright 2018 by Mohammadhossein Tahersima All rights reserved iii Dedicated to my parents. iv Acknowledgments First, I would like to thank my advisor, Prof. Volker Sorger, for agreeing to supervise this interdisciplinary project. I am also indebted to Profs. Can Korman, Anastas Popratiloff, Shahrokh Ahmadi, Mona Zaghloul, Ergun Simsek, Cesare Soci, Ludwig Bartels, Evan Reed, Bala Pesala, and Masahiro Yoshimoto for the many discussions about research, academia, and life in general. I am also grateful to Drs. Danang Birowosuto, Ke Liu, Yigal Lilach, and Christine Brantner, for providing me with precise feedback during my research. I would like to thank my lab mates Zhizhen Ma, Konstantinos Oikonomou, Sikandar Khan, Ameen Elikkottil, Shuai Sun, Rubab Amin, for having a great time working with them. Thanks also go out to my friends: Matteus, Blaire, Jimmy, Ehsan, and Kimberly. Special thanks go to my loving family, Vanessa, Ali, Hanif, Mina, Maryam, Mahmoud and Robab. You define who I am. This work was supported by the National Science Foundation (NSF) Designing Materials to Revolutionize and Engineer our Future (DMREF), East Asia and Pacific Summer Institutes for U.S. Graduate Students (EAPSI), and George Washington University (GWU) fellowships. Furthermore, the Nanofabrication and Imaging Center of GWU and the Center for Nanoscale and Science and Technology (CNST) of National Institute of Standards and Technology (NIST) is hereby acknowledged for technical support. v Abstract of Thesis Enhancement of Light Matter Interaction of Thin Film Materials in Optoelectronic Devices: Plasmonic Antennas, Electro-Optic Modulators, and Solar Cells The most often cited challenge in the field of nanoscale optoelectronics is the weak light matter interaction that has traditionally led to bulky optoelectronic components in scales comparable to the wavelength of light (~500 nm). Recently ultra- thin film (0.5-20 nm) materials have demonstrated to have unique potential for applications in planar optoelectronic and integrated photonics. However, the small optical path across such ultra-thin film materials is the major limiting factor in their optoelectronic performance. In this dissertation, I discuss my PhD research activities in enhancement of light matter interaction of ultra-thin film materials in optical resonant cavities for photo-emission, photo-absorption, and electro-optic modulation application by localizing optical energy in Plasmonic, Fabry-Perot, and Micro-Ring cavities. Transition metal dichalcogenides (TMDs) are stable and naturally occurring semiconductors of two-dimensional (2D) materials that offer well-defined tunable direct band gaps when thinned down to a nanometer. To increase the visible light emission from direct bandgap of TMD monolayers for application in LEDs, nanoscale plasmonic antennae offer a substantial increase of the electric field strength over very short distances, comparable to the native thickness of the TMD. Here I report on the emission enhancement generated in TMD films by several nanoantenna geometries compared to their intrinsic emission. Next, to increase the photo-absorption of TMD thin films further, to compete with thick classical materials, I propose and investigate a novel stack of 2D material vi heterostructure forming a core-shell light-concentrating optical cavity. This structure is motivated by deploying the mechanical flexibility of 2D materials to enable a multilayer solar cell without the necessity to contact each of the layers separately. We further investigate and demonstrate a spectral filtering metasurface for selective guiding of solar spectrum for smart power windows. Finally, Indium tin oxide, that is already an industrial transparent conducting oxide material, shows strong electro-optic tunability in their thin films (~10 nm). I study its application in a novel micro ring reservoir coupling as a wavelength scale CMOS compatible phase modulator on silicon photonic platform. In conclusion, novel nano-photonic components have been proposed and demonstrated to outperform traditional optoelectronics by taking advantage of the unique properties of atomically thin film materials and optical cavities. These finding are important for fast growing application of photonics in lighting, telecommunication, and optical energy conversion. vii Table of Contents Dedication ……………………………………………………………………………… iv Acknowledgement ……………………………………………………………………… v Abstract ………………………………………………………………………………… vi List of Figures …………………………………………………………..……………… x List of Tables ………………………………………………………...………….….… xiii Abbreviations ………………………………………...……………………….……… xiv Chapter 1 Introduction ................................................................................................. 1 1.1 Objective............................................................................................................... 1 1.2 Problem Statement ............................................................................................... 3 1.3 Summary of Main Contributions ........................................................................ 7 1.4 Organization of the Dissertation ......................................................................... 7 Chapter 2 Optoelectronic Properties of Nanoscale Materials .................................. 9 2.1 2D Transition Metal Dichalcogenides................................................................ 9 2.2 Plasmonic Materials .......................................................................................... 15 2.3 Indium Tin Oxide............................................................................................... 19 Chapter 3 Fabry-Perot Cavity in Spiral Solar Cells ................................................ 25 3.1 Introduction ........................................................................................................ 26 3.2 Solar Spectrum Absorption of 2D Materials ................................................... 27 3.3 Van der Waal Heterostructures and Spiral Solar Cell ..................................... 31 3.4 Numerical Methods ........................................................................................... 36 3.5 Results and discussion ....................................................................................... 38 3.6 Conclusion and Outlook .................................................................................... 47 viii Chapter 4 Light Emission Enhancement of 2D Materials in Optical Antennae ... 51 4.1 Introduction ........................................................................................................ 52 4.2 Mie Scattering .................................................................................................... 59 4.3 Field Enhancement ............................................................................................ 64 4.4 Quality Factor and Purcell Effect ..................................................................... 71 4.5 Analytical and Numerical Method ................................................................... 75 4.6 Device Fabrication ............................................................................................. 81 4.7 Measurement ...................................................................................................... 85 4.8 Experimental Results and Discussion .............................................................. 87 Chapter 5 Diffraction Grating for Light Path Engineering .................................... 93 5.1 Introduction ......................................................................................................... 93 5.2 Simulation and Design ........................................................................................ 96 5.3 Fabrication and Testing ....................................................................................... 99 5.4 Conclusion ......................................................................................................... 103 Chapter 6 ITO Ring Resonators
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