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A Multi-Scale Modeling of Graphene N...

Zhang, Weixiang .

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A Multi-Scale Modeling of Graphene Nanoribbon Device in Power Switch Application.

Record Type:	Electronic resources : Monograph/item
Title/Author:	A Multi-Scale Modeling of Graphene Nanoribbon Device in Power Switch Application./
Author:	Zhang, Weixiang .
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2019,
Description:	172 p.
Notes:	Source: Dissertations Abstracts International, Volume: 81-10, Section: B.
Contained By:	Dissertations Abstracts International81-10B.
Subject:	Computational physics. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27738542
ISBN:	9781658422116

A Multi-Scale Modeling of Graphene Nanoribbon Device in Power Switch Application.
Zhang, Weixiang .

A Multi-Scale Modeling of Graphene Nanoribbon Device in Power Switch Application. - Ann Arbor : ProQuest Dissertations & Theses, 2019 - 172 p.

Source: Dissertations Abstracts International, Volume: 81-10, Section: B.

Thesis (Ph.D.)--State University of New York at Buffalo, 2019.

This item must not be sold to any third party vendors.

Graphene has been intensively studied ever since its first experimental isolation in 2004. Its planar form of single-layer atom structure promises great application potentials in various fields. Graphene nanoribbon (GNR), as the most common form of graphene, extract numerous research attention due to its promising electrical, mechanical, thermal properties. For example, unlike gapless graphene, GNR has tunable band gap engineered by width; GNR is very elastic and is stronger than any conventional material; GNR is also extremely thermally conductive, which all combined grants it great potential in many applications including transistors, power switches, electronics interconnector, quantum dots, photovoltaic panel etc. This dissertation reports many findings of mechanical and electrical properties of GNR and GNR-based device from multi-scale simulations based on molecular dynamics simulation, Tight-binding method, Non-Equilibrium Green's Function (NEGF), and Self-Consistent Born Approximation (SCBA), etc. Simulations of the Unravelling process of Armchair and Zigzag GNR is studied using Molecular Dynamics simulations with the Adaptive Intermolecular Reactive Empirical Bond Order (AIREBO) Potential for carbon-carbon bond. Force-Displacement relationship was reported for the terminal atom of the unravelling chains. Key Factors affecting the unravelling process like chirality and locations were discussed.Since the electron dispersion relation of GNR has a special dependency of its dimension in the width direction, the impact of geometry on transport properties can be crucial. This dissertation reports the electron transport properties of undoped armchair GNR Heterojunctions using semi-empirical extended Huckel method (EH) by simulating a two-probe configuration device. Transmission spectrum was analyzed at finite bias; and current-bias voltage characteristic relations were established for different heterojunction geometries.With the geometry impact discussed, we further proposed an electron-static doping based GNR tunneling field-effect transistor (TFET) model. Using the EH method, the transfer characteristics is explored for different device parameter combinations, such as gate-to-gate distance, channel length and width, build-in gate voltage, etc. An optimal device structure is established for high-quality switching performance. The electron-phonon interaction play a significant role in determine the transfer characteristics of the GNR TFET. To better simulate the device performance with more accuracy, the dissipative transport process in GNR TFET is simulated taken into account the effect of phonons using the Quantum Perturbation Theory (QPT) with the Extended Lowest Order Expansion (XLOE) implementation method. The results show that doping level of the source and drain sides of the GNR-TFET has a significant impact on the phonon contribution to the carrier transport process. As temperature increase, the device switching property deteriorates in both the ballistic and dissipative transport regimes. There exists a temperature-dependent critical doping level where the device has optimal switching behavior. Besides phonons, the influence of point defects on the dissipative carrier transport of armchair GNR TFET is also studied. The simulation shows that the presence of defect would introduce additional optical phonon mode of much higher energy, which facilitates the OFF state phonon-assisted Band-to-Band Tunneling (BTBT) process in a broader energy range and contribute to the dissipative carrier transport. While in the ON-state, where the direct source to drain tunneling is at maximum, the electron-phonon interaction has a negligible effect, which is similar to that of the pristine device.

ISBN: 9781658422116Subjects--Topical Terms:

3343998
Computational physics.
Subjects--Index Terms:

Electron-phonon interaction

A Multi-Scale Modeling of Graphene Nanoribbon Device in Power Switch Application.
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245 1 0 $a A Multi-Scale Modeling of Graphene Nanoribbon Device in Power Switch Application.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2019
300 $a 172 p.
500 $a Source: Dissertations Abstracts International, Volume: 81-10, Section: B.
500 $a Advisor: Basaran, Cemal.
502 $a Thesis (Ph.D.)--State University of New York at Buffalo, 2019.
506 $a This item must not be sold to any third party vendors.
506 $a This item must not be sold to any third party vendors.
520 $a Graphene has been intensively studied ever since its first experimental isolation in 2004. Its planar form of single-layer atom structure promises great application potentials in various fields. Graphene nanoribbon (GNR), as the most common form of graphene, extract numerous research attention due to its promising electrical, mechanical, thermal properties. For example, unlike gapless graphene, GNR has tunable band gap engineered by width; GNR is very elastic and is stronger than any conventional material; GNR is also extremely thermally conductive, which all combined grants it great potential in many applications including transistors, power switches, electronics interconnector, quantum dots, photovoltaic panel etc. This dissertation reports many findings of mechanical and electrical properties of GNR and GNR-based device from multi-scale simulations based on molecular dynamics simulation, Tight-binding method, Non-Equilibrium Green's Function (NEGF), and Self-Consistent Born Approximation (SCBA), etc. Simulations of the Unravelling process of Armchair and Zigzag GNR is studied using Molecular Dynamics simulations with the Adaptive Intermolecular Reactive Empirical Bond Order (AIREBO) Potential for carbon-carbon bond. Force-Displacement relationship was reported for the terminal atom of the unravelling chains. Key Factors affecting the unravelling process like chirality and locations were discussed.Since the electron dispersion relation of GNR has a special dependency of its dimension in the width direction, the impact of geometry on transport properties can be crucial. This dissertation reports the electron transport properties of undoped armchair GNR Heterojunctions using semi-empirical extended Huckel method (EH) by simulating a two-probe configuration device. Transmission spectrum was analyzed at finite bias; and current-bias voltage characteristic relations were established for different heterojunction geometries.With the geometry impact discussed, we further proposed an electron-static doping based GNR tunneling field-effect transistor (TFET) model. Using the EH method, the transfer characteristics is explored for different device parameter combinations, such as gate-to-gate distance, channel length and width, build-in gate voltage, etc. An optimal device structure is established for high-quality switching performance. The electron-phonon interaction play a significant role in determine the transfer characteristics of the GNR TFET. To better simulate the device performance with more accuracy, the dissipative transport process in GNR TFET is simulated taken into account the effect of phonons using the Quantum Perturbation Theory (QPT) with the Extended Lowest Order Expansion (XLOE) implementation method. The results show that doping level of the source and drain sides of the GNR-TFET has a significant impact on the phonon contribution to the carrier transport process. As temperature increase, the device switching property deteriorates in both the ballistic and dissipative transport regimes. There exists a temperature-dependent critical doping level where the device has optimal switching behavior. Besides phonons, the influence of point defects on the dissipative carrier transport of armchair GNR TFET is also studied. The simulation shows that the presence of defect would introduce additional optical phonon mode of much higher energy, which facilitates the OFF state phonon-assisted Band-to-Band Tunneling (BTBT) process in a broader energy range and contribute to the dissipative carrier transport. While in the ON-state, where the direct source to drain tunneling is at maximum, the electron-phonon interaction has a negligible effect, which is similar to that of the pristine device.
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650 4 $a Computational physics. $3 3343998
650 4 $a Nanotechnology. $3 526235
650 4 $a Electrical engineering. $3 649834
653 $a Electron-phonon interaction
653 $a Graphene nanoribbon
653 $a Tunneling field effect transistor
690 $a 0216
690 $a 0652
690 $a 0544
710 2 $a State University of New York at Buffalo. $b Civil, Structural and Environmental Engineering. $3 1023703
773 0 $t Dissertations Abstracts International $g 81-10B.
790 $a 0656
791 $a Ph.D.
792 $a 2019
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27738542