DOCSLIB.ORG

Thesis/Dissertation Acceptance

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Thesis/Dissertation Acceptance Graduate School ETD Form 9 (Revised 12/07) PURDUE UNIVERSITY GRADUATE SCHOOL Thesis/Dissertation Acceptance This is to certify that the thesis/dissertation prepared By Neophytos Neophytou Entitled Quantum and Atomistic Effects in Nanoelectronic Transport Devices For the degree of Doctor of Philosophy Is approved by the final examining committee: M. S. Lundstrom Chair G. Klimeck A. Sameh M. Alam To the best of my knowledge and as understood by the student in the Research Integrity and Copyright Disclaimer (Graduate School Form 20), this thesis/dissertation adheres to the provisions of Purdue University’s “Policy on Integrity in Research” and the use of copyrighted material. Approved by Major Professor(s): ____________________________________M. S. Lundstrom ____________________________________ Approved by: M. R. Melloch 5/28/08 Head of the Graduate Program Date Graduate School Form 20 (Revised 10/07) PURDUE UNIVERSITY GRADUATE SCHOOL Research Integrity and Copyright Disclaimer Title of Thesis/Dissertation: Quantum and Atomistic Effects in Nanoelectronic Transport Devices For the degree of ________________________________________________________________ Doctor of Philosophy I certify that in the preparation of this thesis, I have observed the provisions of Purdue University Executive Memorandum No. C-22, September 6, 1991, Policy on Integrity in Research.* Further, I certify that this work is free of plagiarism and all materials appearing in this thesis/dissertation have been properly quoted and attributed. I certify that all copyrighted material incorporated into this thesis/dissertation is in compliance with the United States’ copyright law and that I have received written permission from the copyright owners for my use of their work, which is beyond the scope of the law. I agree to indemnify and save harmless Purdue University from any and all claims that may be asserted or that may arise from any copyright violation. ________________________________Neophytos Neophytou Signature of Candidate 5/28/08 ________________________________ Date *Located at http://www.purdue.edu/policies/pages/teach_res_outreach/c_22.html QUANTUM AND ATOMISTIC EFFECTS IN NANOELECTRONIC TRANSPORT DEVICES A Dissertation Submitted to the Faculty of Purdue University by Neophytos Neophytou In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy December 2008 Purdue University West Lafayette, Indiana ii To my family .... iii ACKNOWLEGEMENTS I am thankful that during my PhD years I was given the opportunity to collaborate and learn from many people from various backgrounds. This for me was a remarkable experience and fun. I would like to express my deep gratitude and appreciation to my advisor, Prof. Mark Lundstrom, who supervised my work. Prof. Lundstrom’s vision and approach towards research, directed towards “doinG what is important and will provide help to the scientific community,” helped me understand how to acquire and use my problem solving skills and attitude. His guidance, through strict professionalism as well as care towards his students, is really admirable, and constitutes true mentoring lessons, beyong the scientific aspect. I would also like to express my Great thankfulness to my co-advisor, Prof. Gerhard Klimeck for his guidance and all the knowledGe I Gained from him. The knowledGe about atomistic simulations as well as about many other new approaches and areas of research that he provided, showed me how broad the science field is. His attitude and persistence towards “getting the project done, and as good as it can get,” as well as his care for his students, is another biG plus for me all these years. I would also like to thank Prof. Ashraful Alam and Prof. Ahmed Sameh, for serving on my advisory committee. Special thanks goes to Dr. Diego Kienle for his endless kindness and patience towards explaining various physics related issues, and providing guidance especially in the early period of my work. His attitude towards research and learning, and his persistence is a great lesson that I got from him. iv I would like to thank Prof. Eric Polizzi for his help in the development of the three-dimensional atomistic simulator for nanotube transistors (CNTFET). I would also like to thank Prof. Shaikh Ahmed for his patience towards the work on the CNTFET simulator deployment. The discussions with him were so beneficial to me in academic and non-academic areas. Thanks go to Dr. Titash Rakshit, Dr. Mark Stettler and Martin Giles for providinG me the opportunity to intern at INTEL Corporation twice and initiate my work on III-V HEMTs. I would like to thank Prof. Supriyo Datta for all the learning I got about the NEGF formalism through his class, Prof. M.P. Anantram for the collaboration in the CNT defect work, and Prof. Gengchiau Liang and Dr. Dmitri Nikonov for the collaboration on the graphene nano-ribbon (GNR) work. I would like to thank my colleagues and labmates for their friendship and fruitful discussions all these years. Thanks goes to Prof. Jing Guo for the initial MATLAB carbon naotube scripts, Dr. Jing Wang, Dr. Anisur Rahman and Dr. Mathieu Luisier for the initial tiGht-bindinG scripts. I would also like to thank Dr. Sayed Hassan, Siyuranga Koswatta, Yang Liu, Kurtis Cantley, Himadri Pal, Raseong Kim, Yunfei Gao, Changwook Jeong, Tony Low, Nick Vargo, Abhijeet Paul, Lutfe Siddiqui, Sayeef Salahuddin, Ninad Pimparkar, Bhaskaran Muralidharan, Neerav Kharche, and all the others in EE350. I feel lucky and Grateful for meetinG these people from whom I learnt so many things. Thanks to Cheryl Haines for her help on travel/meeting arrangements. Thanks goes to the NSF funded Network for Computational Nanotechnology (NCN) center for the computational resources. Finally, I would like to thank my family who stood by me during the whole period of my studies. Special thanks to !"#$$% for her support, patience, and understanding through my entire graduate studies. v TABLE OF CONTENTS Page LIST OF FIGURES ........................................................................................................ viii ABSTRACT ..................................................................................................................... xii 1. INTRODUCTION .........................................................................................................1 1.1. Background......................................................................................................1 1.1.1. 3D device geometry ..........................................................................2 1.1.2. Quantum mechanical effects.............................................................3 1.1.3. Atomistic modeling...........................................................................4 1.2. Summary and contributions .............................................................................6 1.3. Outline of the dissertation................................................................................7 2. QUANTUM SIMULATION OF 3D CNTFET DEVICES - THE EFFECT OF ATOMISTIC DEFECTS IN TRANSPORT PROPERTIES OF 1D CHANNELS .................................................................................................................10 2.1. Introduction....................................................................................................10 2.2. 1D CNT electronic features: Density of states (DOS(E)) and transmission coefficient (T(E)) .....................................................................12 2.3. The effect of atomistic defects on the transport properties of CNTFETs......................................................................................................12 2.3.1. The effect of a vacancy defect ........................................................14 2.3.2. The effect of a negatively charged impurity defect ........................15 2.3.3. The effect of a positively charged impurity defect .........................18 2.3.4. Vacancy defects in metallic CNT channels ....................................18 2.4. Dangling bond defects in ultra scaled cross section nanowires.....................24 2.5. Summary........................................................................................................25 3. SIMULATIONS OF BALLISTIC TRANSPORT IN NANOWIRE TRANSISTORS: A SELF-CONSISTENT ATOMISTIC MODEL ............................26 3.1. Introduction....................................................................................................26 3.2. The empirical nearest-neighbor (NN) sp3d5s* tight-binding (TB) model...............................................................................26 3.3. The simulation scheme ..................................................................................28 3.4. Electronic structure of Si nanowires under bias ............................................32 3.5. sp3d5 s* TB vs. effective mass approximation (EMA) for nanowires ...........35 3.6. Summary........................................................................................................41 vi Page 4. BANDSTRUCTURE EFFECTS IN SILICON NANOWIRE ELECTRON TRANSPORT .........................................................................................43 4.1. Effect of potential variations on the NW dispersion and charge distribution .........................................................................................43 4.2. Device performance comparison of NWs in different orientations...48 4.3. Quantization influence on valley splitting and mass variation ..........53 4.4. Understanding
Load more

Recommended publications
  • Save Our Semiconductors Purdue Researcher Develops New Nano-Simulation Tools on Ranger to Design Smaller Transistors
    Save Our Semiconductors Purdue researcher develops new nano-simulation tools on Ranger to design smaller transistors The semiconductor industry is in peril, experts say. What will these future devices look like? How will they be designed and manufactured? And how can As chips get smaller and smaller, they grow intensely they be optimized quickly to keep the semiconductor hot, power-hungry and unreliable. Furthermore, at industry on track? the nano-regime (10 nanometers and smaller; 5,000 times thinner than a strand of hair), the electrons that flow through semiconductors begin to behave like waves, ruled by the laws of quantum mechanics, and chips lose their efficiency. “The semiconductor industry is going to come to a halt in ten years unless we find design alternatives,” said Gerhard Klimeck, a professor of electrical and computer engineering at Purdue University and as- sociate director for technology at the Network for Computational Nanotechnology (NCN). “We must get away from traditional designs which are, in a sense, one-dimensional, modified layer by layer, and Band-To-Band-Tunneling in InAs Devices: Charge Self-consistent start modifying devices to vary on a three-dimen- Full-Band Transport in Realistic Structure. [Image courtesy of: Ma- sional scale. For that, we need a different simulation thieu Luisier, Gerhard Klimeck] engine.” The answers to these questions have major ramifica- Such a simulator would have to take into account tions, not just for the ubiquitous computer industry, both the quantum behavior and the atomic-level de- but also for detectors, lasers, and green energy solu- tail of their components, which makes them far more tions, all of which will impact our lives.
    [Show full text]
  • Theoretical Study of Strain-Dependent Optical Absorption in a Doped Self-Assembled Inas/Ingaas/Gaas/Algaas Quantum Dot
    Theoretical study of strain-dependent optical absorption in a doped self-assembled InAs/InGaAs/GaAs/AlGaAs quantum dot Tarek A. Ameen*,‡1, Hesameddin Ilatikhameneh*,‡1, Archana Tankasala1, Yuling Hsueh1, James Charles1, Jim Fonseca1, Michael Povolotskyi1, Jun Oh Kim2, Sanjay Krishna3, Monica S. Allen4, Jeffery W. Allen4, Rajib Rahman1 and Gerhard Klimeck1 Full Research Paper Open Access Address: Beilstein J. Nanotechnol. 2018, 9, 1075–1084. 1Network for Computational Nanotechnology, Department of Electrical doi:10.3762/bjnano.9.99 and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA, 2Korean Research Institute of Standards and Sciences, Received: 02 November 2017 Daejeon 34113, South Korea, 3Department of Electrical and Accepted: 09 February 2018 Computer Engineering, Ohio State University, Columbus, OH 43210, Published: 04 April 2018 USA and 4Air Force Research Laboratory, Munitions Directorate, Eglin AFB, FL 32542, USA. This article is part of the Thematic Series "Light–Matter interactions on the nanoscale". Email: Tarek A. Ameen* - [email protected]; Guest Editor: M. Rahmani Hesameddin Ilatikhameneh* - [email protected] © 2018 Ameen et al.; licensee Beilstein-Institut. * Corresponding author ‡ Equal contributors License and terms: see end of document. Keywords: anharmonic atomistic strain model; biaxial strain ratio; configuration interaction; optical absorption; quantum qot filling; self-assembled quantum dots; semi-empirical tight-binding; sp3d5s* with spin–orbit coupling (sp3d5s*_SO) Abstract A detailed theoretical study of the optical absorption in doped self-assembled quantum dots is presented. A rigorous atomistic strain model as well as a sophisticated 20-band tight-binding model are used to ensure accurate prediction of the single particle states in these devices. We also show that for doped quantum dots, many-particle configuration interaction is also critical to accurately capture the optical transitions of the system.
    [Show full text]
  • Gerhard Klimeck V. Virginia Klimeck
    MEMORANDUM DECISION Pursuant to Ind. Appellate Rule 65(D), this Memorandum Decision shall not be regarded as precedent or cited before any court except for the purpose of establishing the defense of res judicata, collateral estoppel, or the law of the case. ATTORNEY FOR APPELLANT ATTORNEY FOR APPELLEE Cynthia Phillips Smith Jennifer Fehrenbach Taylor Lafayette, Indiana Fehrenbach Taylor Law Office Lafayette, Indiana I N T H E COURT OF APPEALS OF INDIANA Gerhard Klimeck, August 11, 2016 Appellant, Court of Appeals Cause No. 79A02-1510-DR-1796 v. Appeal from the Tippecanoe Circuit Court Virginia Klimeck, The Honorable Thomas H. Busch, Appellee. Judge Trial Court Cause No. 79C01-1501-DR-10 Barnes, Judge. Court of Appeals of Indiana | Memorandum Decision 79A02-1510-DR-1796 | August 11, 2016 Page 1 of 19 Case Summary [1] Gerhard Klimeck appeals the denial of the motion to correct error he filed following the trial court’s issuance of findings of fact, conclusions of law, and dissolution decree in his divorce from his wife Virginia Klimeck. We affirm in part, reverse in part, and remand. Issues [2] The restated substantive issues before us are: I. whether the trial court divided the marital estate in a just and reasonable manner; II. whether the trial court abused its discretion by ordering Gerhard to make spousal maintenance payments to Virginia; and III. whether the trial court abused its discretion by imposing a “gag order” on Gerhard with regard to Virginia’s medical conditions and treatment. Facts [3] Gerhard and Virginia were married on July 1, 1995, and have two children.
    [Show full text]
  • Thesis-Franckie-FINAL
    Modeling Quantum Cascade Lasers Modeling Quantum Cascade Lasers: The Challenge of Infra-Red Devices by Martin Franckié Thesis for the degree of Doctor of Philosophy Thesis advisors: Prof. Andreas Wacker, Dr. Claudio Verdozzi Faculty opponent: Prof. Gerhard Klimeck To be presented, with the permission of the Faculty of Science of Lund University, for public criticism in the Rydberg lecture hall (Rydbergsalen) at the Department of Physics on Friday, the 13th of May 2016 at 13:00. Organization Document name LUND UNIVERSITY DOCTORAL DISSERTATION Department of Physics Date of disputation Box 118 2016-05-13 221 00 LUND Sponsoring organization Sweden Author(s) Martin Franckié Title and subtitle Modeling Quantum Cascade Lasers: The Challenge of Infra-Red Devices Abstract The Quantum Cascade Laser (QCL) is a solid state source of coherent radiation in the tera- hertz and mid-infrared parts of the electro-magnetic spectrum. In this thesis, I have used a non-equilibrium Green’s function (NEGF) model to theoretically investigate the quantum nature of the device operation, and compared simulation results to experiments. As simula- tions with the NEGF model are time-consuming, especially for mid-infrared QCLs owing to their large state space, the program has been parallelized to run on large computer clusters. Additional challenges of mid-infrared QCLs are increased interface roughness scattering and non-parabolicity effects, which have been included into the existing NEGF model. With this new model, simulation results in close agreement with experimental
    [Show full text]
  • Bob Eisenberg (More Formally, Robert S
    Bob Eisenberg (more formally, Robert S. Eisenberg) Curriculum Vitae September 11, 2021 Maintained with loving care by John Tang, all these years, with thanks from Bob! Address 7320 Lake Street Unit 5 River Forest IL 60305 USA or PO Box 5409 River Forest IL 60305 USA or Department of Physiology & Biophysics Rush University 1750 West Harrison, Room 1519a Jelke Chicago IL 60612 or Dept of Applied Mathematics Room 106D Pritzker Center, corner of State and 31st Street, Illinois Institute of Technology, Chicago IL 60616 Phone numbers Voice: +1 (708) 932 2597; Rush Department: Voice +1 (312)-942-6454; Rush FAX: (312)-942-8711 FAX to email: (801)-504-8665 Skype name: beisenbe Email: [email protected] Other email:[email protected], [email protected], [email protected] Scopus ID’s are 55552198800 and 7102490928. NIH COMMONS name is BEISENBE. ORCID identifier is 0000-0002-4860-5434 Web of Science ResearcherID is: G-8716-2018 and/or P-6070-2019 Publons Public Profile G-8716-2018 Robert S. Eisenberg https://publons.com/researcher/1941224/robert-s-eisenberg/ NIH maintained “My Bibliography: Bob Eisenberg” at http://goo.gl/Z7a2V7 or https://www.ncbi.nlm.nih.gov/myncbi/browse/collection/47999805/?sort=date&direction=ascending Education Elementary School: New Rochelle, New York High School, 1956-59. Horace Mann School, Riverdale, New York City, graduated in three years with honors and awards in Biology, Chemistry, Physics, Mathematics, Latin, English, and History. An interviewer of J.R. Pappenheimer, Professor of Physiology, Harvard Medical School, on American Heart Sponsored television program, ~1957. p. 1 RS Eisenberg September 11, 2021 Undergraduate, 1959-62.
    [Show full text]
  • Quantum Computing and Decoherence in Silicon Architectures
    SILICON IN THE QUANTUM LIMIT: QUANTUM COMPUTING AND DECOHERENCE IN SILICON ARCHITECTURES by Charles George Tahan A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Physics) at the UNIVERSITY OF WISCONSIN - MADISON 2005 (C) Copyright by Charles G. Tahan 2005 All Rights Reserved i Acknowledgments There are many who deserve the credit for where I am today. First and foremost are my parents, who supported and helped me with all my dreams. My thesis advisor, Robert Joynt, and the University of Wisconsin-Madison Physics Department deserve great credit for giving me a chance to prove myself as a scientist. Bob has been a great advisor. Mark Friesen, who I’ve worked with and bothered extensively over the last four years has been a life saver. Mark Eriksson has been a second advisor to me. The many people I’ve worked with and have had fun doing so deserve attention as well: Keith Slinker, Srijit Goswami, Don Savage, Max Lagally, Ryan Toonen, Hua Qin, Robert Blick, Jim Truitt, Dan van der Weide, Sue Coppersmith, Alex Rimberg, Gerhard Klimeck, and many others, including all my previous mentors and friends. Thank you all very much. ii Abstract The pursuit of spin and quantum entanglement-based devices in solid-state systems has become a global endeavor. The approach of the quantum size limit in computer electronics, the many recent advances in nanofabrication, and the rediscovery that information is physical (and thus based on quantum physics) have started a worldwide race to understand and control quantum systems in a coherent and useful way.
    [Show full text]
  • PURDUE UNIVERSITY GRADUATE SCHOOL Thesis/Dissertation Acceptance
    Graduate School ETD Form 9 (Revised 12/07) PURDUE UNIVERSITY GRADUATE SCHOOL Thesis/Dissertation Acceptance This is to certify that the thesis/dissertation prepared By Himadri S. Pal Entitled Device Physics Studies of III-V and Silicon MOSFETs for Digital Logic For the degree of Doctor of Philosophy Is approved by the final examining committee: MARK S. LUNDSTROM Chair GERHARD KLIMECK PEIDE YE SUPRIYO DATTA To the best of my knowledge and as understood by the student in the Research Integrity and Copyright Disclaimer (Graduate School Form 20), this thesis/dissertation adheres to the provisions of Purdue University’s “Policy on Integrity in Research” and the use of copyrighted material. MARK S. LUNDSTROM Approved by Major Professor(s): ____________________________________ ____________________________________ Approved by: V. Balakrishnan 09-27-2010 Head of the Graduate Program Date Graduate School Form 20 (Revised 6/09) PURDUE UNIVERSITY GRADUATE SCHOOL Research Integrity and Copyright Disclaimer Title of Thesis/Dissertation: Device Physics Studies of III-V and Silicon MOSFETs for Digital Logic For the degree of ________________________________________________________________Doctor of Philosophy I certify that in the preparation of this thesis, I have observed the provisions of Purdue University Executive Memorandum No. C-22, September 6, 1991, Policy on Integrity in Research.* Further, I certify that this work is free of plagiarism and all materials appearing in this thesis/dissertation have been properly quoted and attributed. I certify that all copyrighted material incorporated into this thesis/dissertation is in compliance with the United States’ copyright law and that I have received written permission from the copyright owners for my use of their work, which is beyond the scope of the law.
    [Show full text]
  • INNOV Emerg Tech.Qxp
    INNOVATIONS IN MATERIALS TECHNOLOGY EMERGING TECHNOLOGY Nanoscience computational tools developed for Internet BRIEFS A five-year, $18.25 million grant from the National Carl Zeiss SMT Science Foundation to support the U.S. National announces that Nanotechnology Initiative with expanded capabili- Harvard University’s ties and services for computer simulations on the In- Faculty for Arts and Sciences has selected ternet has been received by the Purdue University eight Zeiss scanning and Network for Computational Nanotechnology, West transmission electron Lafayette, Ind. microscopes, focused- “With the help of our five partner universities, we ion-beam analytical are growing beyond our roots in nanoelectronics to systems, and one of the new areas such as nanofluidics, nanomedicine, world’s first helium ion nanophotonics and applications of nanoscience to the microscopes for its environment, energy, the life sciences, and homeland Center for Nanoscale security,” says network director Mark Lundstrom. Systems. www.zeiss.smt.com The gateway for this global network is the nanoHUB, a free Internet-based science gateway This image of a quantum dot was produced by a simulation via the nanoHUB. This image shows the The Center for used by more than 3000 national and international computed second excited electron state of a quantum Nanoscale Materials researchers and educators every month. In addition dot nanodevice in which electrons resonate and emit at the Department of to online simulation services, the site’s menu includes pure bright light. (Image by Wei Qiao, David Ebert, Energy’s Argonne courses, tutorials, seminars, podcasts, and reviews Makerk Korkusinski, Gerhard Klimeck) National Laboratory of tools and content.
    [Show full text]
  • Electrical and Computer Engineering Department the University of Alabama in Huntsville
    Electrical and Computer Engineering Department The University of Alabama in Huntsville Spring 2006 2006 College of Engineering Distinguished Engineer Alumni Dr. Robert Lindquist Three ECE Alumni received prestigious Distinguished Engineer Alumni awards from the College of Engineering in May 2006. Stages Named Director of of the ceremony are pictured below. The citations are on pages 6 & 7. UAH Center for Applied Optics Dr. Robert Lindquist was named Director of the Center for Applied Optics in Fall 2005. Dr. Lindquist returned to the ECE Department as Professor in the Electrical and Optical Engineering programs in August 2003 after spending six years at the Corning Incorporated research facility in Corning, NY. He received both the Ph.D. and B.S. degrees in Electrical and Computer Engineering at The Pennsylvania State University in 1992 and 1986, respectively. He brought liquid Dr. Haik Biglari and Dean Aunon Listen to the Citation Reading crystal fabrication equipment with him to UAH, adding to existing micro and nanofabrication capabilities. At Corning Incorporated, Dr. Lindquist worked in the areas of liquid crystal devices for optical networking, electronics on glass for display and SOI applications. His work at Corning lead to the product launch of the PurePath™ wavelength selective switch and dynamic spectral equalizer, which was awarded an OFC 2000 Top Ten Product Award. Dr. Lindquist holds eight patents related to his work at Corning. In addition to his teaching as Professor of ECE and his duties as Director of the CAO, Dr. Lindquist will continue his research on optical networking devices and liquid crystal components. He will continue to collaborate with Corning Inc.
    [Show full text]
  • Curriculum Vitae
    Curriculum Vitae Yong P. Chen Karl Lark-Horovitz Professor of Physics and Astronomy and Professor of Electrical and Computer Engineering, Director of Purdue Quantum Science and Engineering Institute (PQSEI) Department of Physics and Astronomy, School of Electrical and Computer Engineering and Birck Nanotechnology Center, Purdue University, 525 Northwestern Ave, West Lafayette, IN 47907 (currently on sabbatical leave) Villum Investigator and Professor (dual appointment), Dept. of Physics and Astronomy, Aarhus University, 120 Ny Munkegade, 8000 Aarhus C, Denmark Principal Investigator, WPI (World Premier International Research Center)-AIMR (Advanced Institute for Materials Research), Tohoku University, Sendai, Japan Associate Editor, AVS-Quantum Science (AQS), American Institute for Physics Tel: +1 (765) 494-0947 Fax: +1 (765) 494-0706 Email: [email protected] Web: http://www.physics.purdue.edu/people/faculty/yongchen.shtml https://pure.au.dk/portal/en/persons/yong-chen(dbfdb176-599c-4897-989f- 91f1a240f495).html https://www.wpi-aimr.tohoku.ac.jp/en/research/researcher/chen_y.html Research Group Web: http://www.physics.purdue.edu/quantum (Chen Lab @ Purdue) https://www.wpiaimr.tohoku.ac.jp/qms_lab/ (Chen-Kumatani-Tanigaki Lab @ AIMR) Personal: Born Oct. 1979, Chinese/Macau SAR Citizen, US Permanent Resident Degree Education Ph.D., Princeton University (1999–2005) Major: Electrical Engineering (Solid State Physics/Electronic Materials and Devices) Ph.D. Thesis: Quantum Solids of Two Dimensional Electrons in Magnetic Fields Thesis Advisor: Daniel C. Tsui (Nobel Laureate Physics’98) M.Sc., MIT (1997–1999) Major: Mathematics (passed PhD qualifying exam) Advisor: Gian-Carlo Rota MS Thesis: Model Order Reduction for Nonlinear Systems Thesis Advisor: Jacob White B.Sc., Xi’an Jiaotong University (1992–1996) Major: Applied Mathematics B.Sc.
    [Show full text]
  • Quantitative Excited State Spectroscopy of a Single Ingaas Quantum Dot Molecule Through Multi-Million Atom Electronic Structure Calculations
    Quantitative Excited State Spectroscopy of a Single InGaAs Quantum Dot Molecule through Multi-million Atom Electronic Structure Calculations Muhammad Usman1, *, Yui-Hong Matthias Tan1, *, Hoon Ryu1, Shaikh S. Ahmed2, Hubert Krenner3, Timothy B. Boykin4, and Gerhard Klimeck1 *Co-first authors, contributed equally 1School of Electrical and Computer Engineering and Network for Computational Nanotechnology, Purdue University, West Lafayette Indiana, 47906 USA 2Department of Electrical and Computer Engineering, Southern Illinois University at Carbondale, Carbondale, IL, 62901 USA 3Lehrstuhl für Experimentalphysik 1, Universität Augsburg, Universitätsstr. 1, 86159 Augsburg, Germany 4Department of Electrical and Computer Engineering, University of Alabama in Huntsville, Huntsville, AL, 35899, USA Atomistic electronic structure calculations are performed to study the coherent inter-dot couplings of the electronic states in a single InGaAs quantum dot molecule. The experimentally observed excitonic spectrum by H. Krenner et al. [12] is quantitatively reproduced, and the correct energy states are identified based on a previously validated atomistic tight binding model. The extended devices are represented explicitly in space with 15 million atom structures. An excited state spectroscopy technique is applied where the externally applied electric field is swept to probe the ladder of the electronic energy levels (electron or hole) of one quantum dot through anti-crossings with the energy levels of the other quantum dot in a two quantum dot molecule. This technique can be used to estimate the spatial electron-hole spacing inside the quantum dot molecule as well as to reverse engineer quantum dot geometry parameters such as the quantum dot separation. Crystal deformation induced piezoelectric effects have been discussed in the literature as minor perturbations lifting degeneracies of the electron excited (P and D) states, thus affecting polarization alignment of wave function lobes for III-V Heterostructures such as single InAs/GaAs quantum dots.
    [Show full text]
  • A Three-Dimensional Simulation Study of the Performance of Carbon
    Università di Pisa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three-dimensional simulation study of the performance of carbon nanotube field-effect transistors with doped reservoirs and realistic geometry,ƞ IEEE Transactions on Electron Devices, 53 , 8, pp.1782-1788 (2006). # # 1782 IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 53, NO. 8, AUGUST 2006 A Three-Dimensional Simulation Study of the Performance of Carbon Nanotube Field-Effect Transistors With Doped Reservoirs and Realistic Geometry Gianluca Fiori, Giuseppe Iannaccone, Member, IEEE, and Gerhard Klimeck, Senior Member, IEEE Abstract—This paper simulates the expected device perfor- induced barrier lowering (DIBL), it has been demonstrated that mance and scaling perspectives of carbon nanotube (CNT) field- the downscaling of device dimensions has to follow particular effect transistors with doped source and drain extensions. The rules, like maintaining the ratio between the channel length and simulations are based on the self-consistent solution of the three- dimensional Poisson–Schrödinger equation with open boundary the oxide thickness larger than 18 [5]. conditions, within the nonequilibrium Green’s function formal- To alleviate these problems, different solutions have been ism, where arbitrary gate geometry and device architecture can be proposed to achieve channel modulation of the barrier.
    [Show full text]