Engineering patterns of wrinkles and bubbles in supported graphene through modeling and simulation
Graphene deposited on a substrate often exhibits out-of-plane deformations with different features and origins. Networks of localized wrinkles have been observed in graphene synthesized through CVD, as a result of compressive stresses transmitted by the substrate. Graphene blisters have been reporte...
| Autor: | |
|---|---|
| Tipo de documento: | tese |
| Data de publicação: | 2015 |
| País: | España |
| Recursos: | Universitat Politècnica de Catalunya (UPC) |
| Repositório: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglês |
| OAI Identifier: | oai:upcommons.upc.edu:2117/95739 |
| Acesso em linha: | https://hdl.handle.net/2117/95739 https://dx.doi.org/10.5821/dissertation-2117-95739 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Grafè Deformacions (Mecànica) -- Mètodes de simulació Àrees temàtiques de la UPC::Matemàtiques i estadística |
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España |
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Engineering patterns of wrinkles and bubbles in supported graphene through modeling and simulation |
| title |
Engineering patterns of wrinkles and bubbles in supported graphene through modeling and simulation |
| spellingShingle |
Engineering patterns of wrinkles and bubbles in supported graphene through modeling and simulation Zhang, Kuang Grafè Deformacions (Mecànica) -- Mètodes de simulació Àrees temàtiques de la UPC::Matemàtiques i estadística |
| title_short |
Engineering patterns of wrinkles and bubbles in supported graphene through modeling and simulation |
| title_full |
Engineering patterns of wrinkles and bubbles in supported graphene through modeling and simulation |
| title_fullStr |
Engineering patterns of wrinkles and bubbles in supported graphene through modeling and simulation |
| title_full_unstemmed |
Engineering patterns of wrinkles and bubbles in supported graphene through modeling and simulation |
| title_sort |
Engineering patterns of wrinkles and bubbles in supported graphene through modeling and simulation |
| dc.creator.none.fl_str_mv |
Zhang, Kuang |
| author |
Zhang, Kuang |
| author_facet |
Zhang, Kuang |
| author_role |
author |
| dc.contributor.none.fl_str_mv |
Arroyo Balaguer, Marino |
| dc.subject.none.fl_str_mv |
Grafè Deformacions (Mecànica) -- Mètodes de simulació Àrees temàtiques de la UPC::Matemàtiques i estadística |
| topic |
Grafè Deformacions (Mecànica) -- Mètodes de simulació Àrees temàtiques de la UPC::Matemàtiques i estadística |
| description |
Graphene deposited on a substrate often exhibits out-of-plane deformations with different features and origins. Networks of localized wrinkles have been observed in graphene synthesized through CVD, as a result of compressive stresses transmitted by the substrate. Graphene blisters have been reported with various sizes and shapes, and have been shown to be caused by gas trapped between graphene and substrate. Such wrinkles or bubbles locally modify the electronic properties and are often seen as defects. It has been also suggested that the strong coupling between localized deformation and electronic structure can be potentially harnessed in technology by strain engineering, although it has not been possible to precisely control the geometry of out-of-plane deformations, partly due to an insufficent theoretical understanding of the underlying mechanism, particularly under biaxial strains. The specific contributions of the thesis are outlined next. Firstly, we study the emergence of spontaneous wrinkling in supported and laterally strained graphene with high-fidelity simulations based on an atomistically informed continuum model. With a simpler theoretical model, we characterize the onset of buckling and the nonlinear behavior after the instability in terms of the adhesion and frictional material parameters of the graphene-substrate interface. We find that a distributed rippling linear instability transits to localized wrinkles due to the nonlinearity in the van der Waals graphene-substrate interactions. We identify friction as a selection mechanism for the separation between wrinkles, because the formation of far apart wrinkles is penalized by the work of friction. Secondly, we examine the mechanics of wrinkling in supported graphene upon biaxial strains. With realistic simulations and an energetic analysis, we understand how strain anisotropy, adhesion and friction govern spontaneous wrinkling. We then propose a strategy to control the location of wrinkles through patterns of weaker adhesion. These mechanically self-assembled networks are stable under the pressure produced by an enclosed fluid and form continuous channels, opening the door to nano-fluidic applications. Finally, we examine the coexistence of wrinkles and blisters in supported graphene. By changing the applied strain and gas mass trapped beneath the graphene sample, we build a morphological diagram determining the size and shape of graphene bubbles, and their coexistence with wrinkles. As a whole, the research described above depicts a systematic and broad understanding of out-of-plane deformations in monolayer graphene on a substrate, and could be a theoretical foundation towards strain engineering in supported graphene. |
| publishDate |
2015 |
| dc.date.none.fl_str_mv |
2015 2015-06-10 2015 2015-10-05 |
| dc.type.none.fl_str_mv |
doctoral thesis http://purl.org/coar/resource_type/c_db06 VoR http://purl.org/coar/version/c_970fb48d4fbd8a85 |
| dc.type.openaire.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
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doctoralThesis |
| dc.identifier.none.fl_str_mv |
https://hdl.handle.net/2117/95739 https://dx.doi.org/10.5821/dissertation-2117-95739 |
| url |
https://hdl.handle.net/2117/95739 https://dx.doi.org/10.5821/dissertation-2117-95739 |
| dc.language.none.fl_str_mv |
Inglés eng |
| language_invalid_str_mv |
Inglés |
| language |
eng |
| dc.rights.none.fl_str_mv |
open access http://purl.org/coar/access_right/c_abf2 |
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info:eu-repo/semantics/openAccess |
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open access http://purl.org/coar/access_right/c_abf2 |
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openAccess |
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application/pdf |
| dc.publisher.none.fl_str_mv |
Universitat Politècnica de Catalunya |
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Universitat Politècnica de Catalunya |
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reponame:UPCommons. Portal del coneixement obert de la UPC instname:Universitat Politècnica de Catalunya (UPC) |
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Universitat Politècnica de Catalunya (UPC) |
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UPCommons. Portal del coneixement obert de la UPC |
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UPCommons. Portal del coneixement obert de la UPC |
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1869411562541809664 |
| spelling |
Engineering patterns of wrinkles and bubbles in supported graphene through modeling and simulationZhang, KuangGrafèDeformacions (Mecànica) -- Mètodes de simulacióÀrees temàtiques de la UPC::Matemàtiques i estadísticaGraphene deposited on a substrate often exhibits out-of-plane deformations with different features and origins. Networks of localized wrinkles have been observed in graphene synthesized through CVD, as a result of compressive stresses transmitted by the substrate. Graphene blisters have been reported with various sizes and shapes, and have been shown to be caused by gas trapped between graphene and substrate. Such wrinkles or bubbles locally modify the electronic properties and are often seen as defects. It has been also suggested that the strong coupling between localized deformation and electronic structure can be potentially harnessed in technology by strain engineering, although it has not been possible to precisely control the geometry of out-of-plane deformations, partly due to an insufficent theoretical understanding of the underlying mechanism, particularly under biaxial strains. The specific contributions of the thesis are outlined next. Firstly, we study the emergence of spontaneous wrinkling in supported and laterally strained graphene with high-fidelity simulations based on an atomistically informed continuum model. With a simpler theoretical model, we characterize the onset of buckling and the nonlinear behavior after the instability in terms of the adhesion and frictional material parameters of the graphene-substrate interface. We find that a distributed rippling linear instability transits to localized wrinkles due to the nonlinearity in the van der Waals graphene-substrate interactions. We identify friction as a selection mechanism for the separation between wrinkles, because the formation of far apart wrinkles is penalized by the work of friction. Secondly, we examine the mechanics of wrinkling in supported graphene upon biaxial strains. With realistic simulations and an energetic analysis, we understand how strain anisotropy, adhesion and friction govern spontaneous wrinkling. We then propose a strategy to control the location of wrinkles through patterns of weaker adhesion. These mechanically self-assembled networks are stable under the pressure produced by an enclosed fluid and form continuous channels, opening the door to nano-fluidic applications. Finally, we examine the coexistence of wrinkles and blisters in supported graphene. By changing the applied strain and gas mass trapped beneath the graphene sample, we build a morphological diagram determining the size and shape of graphene bubbles, and their coexistence with wrinkles. As a whole, the research described above depicts a systematic and broad understanding of out-of-plane deformations in monolayer graphene on a substrate, and could be a theoretical foundation towards strain engineering in supported graphene.La deposición de grafeno sobre un substrato a menudo exhibe deformaciones fuera del plano con diversas características y orígenes. Al sintetizar grafeno se han observado mediante CVD redes de arrugas localizadas, como resultado de tensiones de compresión transmitidas por el sustrato. Mientras tanto ha sido posible identificar el gas atrapado entre el grafeno y el sustrato como el responsable del origen de ampollas de tamaños y formas diversos. Tanto las arrugas como las burbujas modifican localmente las propiedades electrónicas, lo que a menudo se considera como defectos. También se ha sugerido que el fuerte acoplamiento entre la deformación localizada y la estructura electrónica podría ser tecnológicamente aprovechada mediante la ingeniería de deformación. Desafortunadamente hasta el presente no ha sido posible controlar con precisión la geometría de las deformaciones fuera del plano, en parte debido a una insuficiente comprensión teórica del mecanismo subyacente, especialmente bajo deformaciones biaxiales. Las contribuciones específicas de la presente tesis se describen a continuación. En primer lugar, estudiamos la aparición espontánea de arrugas en muestras de grafeno simplemente apoyadas y lateralmente tensionadas mediante simulaciones de alta fidelidad, con base en un modelo continuo atomísticamente informado. A través de un modelo teórico simple caracterizamos la aparición de pandeo y el comportamiento no lineal, después de la inestabilidad, en términos de los parámetros de adhesión y de fricción de la interfaz grafeno-sustrato. Encontramos que una ondulación distribuida de una inestabilidad lineal transita hacia arrugas localizadas debido a la no linealidad en las interacciones de van der Waals entre el grafeno y el substrato. Identificamos la fricción como un mecanismo de selección para la separación entre las arrugas, debido a que la formación de arrugas distantes es penalizada por el trabajo de fricción. En segundo lugar, analizamos la mecánica de arrugas en grafeno apoyado bajo deformaciones biaxiales. Mediante simulaciones realistas y un análisis energético, entendemos cómo la deformación anisotropíca, la adherencia y la fricción gobiernan la rugosidad espontánea. Consecuentemente, proponemos una estrategia para controlar la ubicación de las arrugas a través de patrones de débil adherencia. Estas redes mecánicamente auto-ensambladas son estables bajo la presión producida por un fluido encerrado y forman canales continuos, posibilitando el desarrollo de aplicaciones de nano fluidos. Finalmente, analizamos la coexistencia de arrugas y de ampollas en muestras de grafeno apoyado. Mediante el control de la deformación aplicada así como de la masa de gas atrapada debajo de la muestra de grafeno, construimos un diagrama morfológico para determinar el tamaño y la forma de burbujas de grafeno, y su coexistencia con las arrugas. En su conjunto, la investigación descrita anteriormente representa una comprensión sistemática y amplia de las deformaciones fuera del plano en muestras de grafeno monocapa apoyadas sobre un sustrato, y podría servir como fundamento teórico en la incipiente área de ingeniería de deformación en grafeno.Universitat Politècnica de CatalunyaArroyo Balaguer, Marino20152015-06-1020152015-10-05doctoral thesishttp://purl.org/coar/resource_type/c_db06VoRhttp://purl.org/coar/version/c_970fb48d4fbd8a85info:eu-repo/semantics/doctoralThesisapplication/pdfhttps://hdl.handle.net/2117/95739https://dx.doi.org/10.5821/dissertation-2117-95739reponame:UPCommons. Portal del coneixement obert de la UPCinstname:Universitat Politècnica de Catalunya (UPC)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2info:eu-repo/semantics/openAccessoai:upcommons.upc.edu:2117/957392026-05-27T15:37:01Z |
| score |
15,228081 |