Electrical and thermal transport characterization of CVD-grown graphene/multi-walled carbon nanotube and their application in nanocomposites = 화학기상증착법으로 합성한 그래핀의 전기⦁열 전달 특성과 다층탄소나노튜브를 적용한 나노복합체의 응용

다국어 초록 (Multilingual Abstract)

Graphene and carbon nanotube have been receiving significant attentions due to their extremely high mechanical, electrical, and thermal properties. From the unique physical properties, numerous studies have been conducted and are continuously carried out in various research fields. However, the intrinsic physical properties of graphene and carbon nanotube are weakened by their low crystallinity and structural imperfection, so that it is still demanded to develop efficient synthesis process for improving their crystallinity and structure. Here, by optimizing surface condition of catalytic copper (Cu) substrate such as roughness and lattice plane, we could synthesize high-quality monolayer graphene using low pressure chemical vapor deposition (LPCVD). Then, we evaluated electrical and thermal transport properties of the synthesized graphene. In addition, we have systematically studied metals (Ag-Ni) or semiconductor (WS2) based functional composites with inclusion of pure multi-walled carbon nanotubes (MWNTs) or silver coated MWNTs (nAgMWNTs). The one-dimensional carbon nanomaterials modulated electrical, mechanical, or thermal properties of the functional composites to enhance their performance. The physical properties of the functional composites were considerably changed by concentration, interfacial contact, and dispersion of the one-dimensional carbon nanomaterials.

목차 (Table of Contents)

• Table of Contents 1
• Nomenclature 1
• List of Figures 3
• List of Tables 12
• Abstract 13
• Chapter 1 Introduction 15
• 1.1 Background 15
• 1.1.1 Carbon nanomaterials: graphene and carbon nanotube 16
• 1.1.2 Electrical and thermal conductivity of graphene and carbon nanotube 18
• 1.2 Research Objectives and Approaches 25
• 1.2.1 High-quality graphene synthesis on Cu substrate using chemical vapor deposition 25
• 1.2.2 Misorientation-angle dependent thermal conductivity of suspended monolayer graphene 25
• 1.2.3 Multi-walled carbon nanotube (MWNTs) and their applications 26
• Chapter 2 Enhanced electrical transport properties of graphene films by controlling the surface roughness of Cu foils 27
• 2.1 Introduction 27
• 2.2 Experimental details 28
• 2.2.1 Surface preparation of Cu substrates 28
• 2.2.2 Synthesis and transfer of graphene 29
• 2.2.3 Characterization 30
• 2.3 Results and discussion 32
• 2.4 Conclusion 42
• Chapter 3 Dramatically reduced thermal conductivity of suspended graphene by slight misorientation angle 51
• 3.1 Introduction 51
• 3.2 Experimental details 52
• 3.2.1 Surface treatment of Cu(111) substrate and graphene synthesis 52
• 3.2.2 Transfer process of graphene 53
• 3.2.3 Characterization 53
• 3.2.4 Theoretical approach for thermal conductivity of graphene 54
• 3.3 Results and discussion 58
• 3.4 Conclusion 68
• Chapter 4 Enhanced electrical conductivity and Vickers hardness of silver-nickel composites by silver-plated multi-walled carbon nanotubes 75
• 4.1 Introduction 75
• 4.2 Experimental details 77
• 4.2.1 Synthesis of nAgMWNTs 77
• 4.2.2 Spark plasma sintering of composites 78
• 4.2.3 Characterization 79
• 4.3 Results and discussion 80
• 4.4 Conclusion 88
• Chapter 5 Enhanced Thermoelectric figure of merit of Tungsten Disulfide-Multiwalled Carbon Nanotube Composites 96
• 5.1 Introduction 96
• 5.2 Experimental details 98
• 5.2.1 Sintering process of WS2-MWNT composites 98
• 5.2.2 Characterization 99
• 5.3 Results and discussion 99
• 5.4 Conclusion 106
• Chapter 6 Summary and Future work 116
• 6.1 Summary 116
• 6.2 Future work 118
• References 119
• 논문요약 126