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 recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2015 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/311440 |
| Acceso en línea: | http://hdl.handle.net/10803/311440 https://dx.doi.org/10.5821/dissertation-2117-95739 |
| Access Level: | acceso abierto |
| Palabra clave: | 517 531/534 |
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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 517 531/534 |
| 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 Universitat Politècnica de Catalunya. Departament de Matemàtica Aplicada III |
| dc.subject.none.fl_str_mv |
517 531/534 |
| topic |
517 531/534 |
| 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 |
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2015 2015 2015 |
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info:eu-repo/semantics/doctoralThesis info:eu-repo/semantics/publishedVersion |
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doctoralThesis |
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publishedVersion |
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http://hdl.handle.net/10803/311440 https://dx.doi.org/10.5821/dissertation-2117-95739 |
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http://hdl.handle.net/10803/311440 https://dx.doi.org/10.5821/dissertation-2117-95739 |
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Inglés |
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Inglés |
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info:eu-repo/semantics/openAccess |
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openAccess |
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89 p. application/pdf application/pdf |
| dc.publisher.none.fl_str_mv |
Universitat Politècnica de Catalunya |
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Universitat Politècnica de Catalunya |
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TDX (Tesis Doctorals en Xarxa) reponame:TDR. Tesis Doctorales en Red instname:CBUC, CESCA |
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CBUC, CESCA |
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TDR. Tesis Doctorales en Red |
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TDR. Tesis Doctorales en Red |
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1869409151432523776 |
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Engineering patterns of wrinkles and bubbles in supported graphene through modeling and simulationZhang, Kuang517531/534Graphene 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.DOCTORAT EN MATEMÀTICA APLICADA (Pla 2007)Universitat Politècnica de CatalunyaArroyo Balaguer, MarinoUniversitat Politècnica de Catalunya. Departament de Matemàtica Aplicada III201520152015info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersion89 p.application/pdfapplication/pdfhttp://hdl.handle.net/10803/311440https://dx.doi.org/10.5821/dissertation-2117-95739TDX (Tesis Doctorals en Xarxa)reponame:TDR. Tesis Doctorales en Redinstname:CBUC, CESCAInglésADVERTIMENT. L'accés als continguts d'aquesta tesi doctoral i la seva utilització ha de respectar els drets de la persona autora. Pot ser utilitzada per a consulta o estudi personal, així com en activitats o materials d'investigació i docència en els termes establerts a l'art. 32 del Text Refós de la Llei de Propietat Intel·lectual (RDL 1/1996). Per altres utilitzacions es requereix l'autorització prèvia i expressa de la persona autora. En qualsevol cas, en la utilització dels seus continguts caldrà indicar de forma clara el nom i cognoms de la persona autora i el títol de la tesi doctoral. No s'autoritza la seva reproducció o altres formes d'explotació efectuades amb finalitats de lucre ni la seva comunicació pública des d'un lloc aliè al servei TDX. Tampoc s'autoritza la presentació del seu contingut en una finestra o marc aliè a TDX (framing). Aquesta reserva de drets afecta tant als continguts de la tesi com als seus resums i índexs.info:eu-repo/semantics/openAccessoai:www.tdx.cat:10803/3114402026-06-14T12:46:07Z |
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15,300719 |