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Growth of Millimeter-Sized Graphene Single Crystals on Al <sub/>2</sub> O <sub/>3</sub> (0001)/Pt(111) Template Wafers Using Chemical Vapor Deposition
摘要： The synthesis of graphene using chemical vapor deposition on platinum surfaces is discussed. The crystalline nature of the platinum substrates as well as the graphene growth conditions play a key role to yield monolayer graphene with low defectivity. The need for template wafers with a single Pt orientation emerges due to graphene overgrowth on untextured polycrystalline Pt foils. Single-crystalline Pt foils can be obtained after long annealing steps. However, these Pt foils remain rough and are therefore less suitable during subsequent graphene transfer procedures. On the other hand, highly oriented platinum thin films avoid the overgrowth issues but result in differing nucleation phenomena on different oriented grains. An optimized graphene growth template is found in Al2O3(0001)/Pt(111), which is more than one order of magnitude flatter compared to the annealed Pt(111) foils and serves as an ideal catalyst to grow graphene grains exceeding 7 mm in diameter.
关键词： chemical vapor deposition,single crystals,platinum,Al2O3(0001)/Pt(111),graphene
更新于2025-09-04 15:30:14
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Material Reliability of Low-Temperature Boron Deposition for PureB Silicon Photodiode Fabrication
摘要： The chemical-vapor deposition conditions for the growth of pure boron (PureB) layers on silicon at temperatures as low as 400oC were investigated with the purpose of optimizing photodiodes fabricated with PureB anodes for minimal B-layer thickness, low dark current and chemical robustness. The B-deposition is performed in a commercially-available Si epitaxial reactor from a diborane precursor. In-situ methods commonly used to improve the cleanliness of the Si surface before deposition are tested for a deposition temperature of 450oC and PureB layer thickness of 3 nm. Specifically, high-temperature baking in hydrogen, and exposure to HCl are tested. Both material analysis and electrical diode characterization indicate that these extra cleaning steps degrade the properties of the PureB layer and the fabricated diodes.
关键词： silicon,photodiodes,chemical-vapor deposition,Pure boron,diborane
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - Singapore, Singapore (2018.4.22-2018.4.26)] 2018 IEEE 13th Annual International Conference on Nano/Micro Engineered and Molecular Systems (NEMS) - A Novel Method for Fabricating Graphene Sensors in Channel for Biomedical Applications
摘要： Graphene is a 2D material possessing extraordinary electrical, mechanical and optical properties which paves way for fabricate biomedical applications. A well-known method graphene-based devices is depositing graphene using chemical vapor deposition and transferring it to any substrate using polymer support like PDMS (Polydimethylsiloxane). In this process multiple wetting and drying steps are required which compromises the quality of graphene. Also, PMMA leaves residues that are difficult to remove. Here, we report a novel method to fabricate graphene sensors inside PDMS channels. In this method graphene/copper stack is bonded on a PDMS surface using mechanical pressure and temperature. This PDMS layer is then bonded to another PDMS substrate containing microchannel. Etchant is flown through the microchannel to etch the copper and obtain graphene on PDMS. The graphene obtained on PDMS is characterized using optical images, scanning electron microscopy and Raman spectroscopy. This is an easy, simple to use and scalable method to obtain graphene sensors inside microchannels for biomedical applications.
关键词： Chemical Vapor Deposition,Biomedical Applications,Microchannel,Graphene,PDMS
更新于2025-09-04 15:30:14
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Site‐Selective and van der Waals Epitaxial Growth of Rhenium Disulfide on Graphene
摘要： The surface property of growth substrate imposes significant influence in the growth behaviors of 2D materials. Rhenium disulfide (ReS2) is a new family of 2D transition metal dichalcogenides with unique distorted 1T crystal structure and thickness-independent direct bandgap. The role of growth substrate is more critical for ReS2 owing to its weak interlayer coupling property, which leads to preferred growth along the out-of-plane direction while suppressing the uniform in-plane growth. Herein, graphene is introduced as the growth substrate for ReS2 and the synthesis of graphene/ReS2 vertical heterostructure is demonstrated via chemical vapor deposition. Compared with the rough surface of SiO2/Si substrate with dangling bonds which hinders the uniform growth of ReS2, the inert and smooth surface nature of graphene sheet provides a lower energy barrier for migration of the adatoms, thereby promoting the growth of ReS2 on the graphene surface along the in-plane direction. Furthermore, patterning of the graphene/ReS2 heterostructure is achieved by the selective growth of ReS2, which is attributed to the strong binding energy between sulfur atoms and graphene surface. The fundamental studies in the role of graphene as the growth template in the formation of van der Waals heterostructures provide better insights into the synthesis of 2D heterostructures.
关键词： rhenium disulfide,chemical vapor deposition,2D heterostructures,graphene,site-selective growth
更新于2025-09-04 15:30:14
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Graphene Synthesis by Plasma-Enhanced CVD Growth with Ethanol
摘要： A modified route to synthesize graphene flakes is proposed using the Chemical Vapor Deposition (CVD) technique, by using copper substrates as supports. The carbon source used was ethanol, the synthesis temperature was 950°C and the pressure was controlled along the whole process. In this CVD synthesis process the incorporation of the carbon source was produced at low pressure and 950°C inducing the appearance of a plasma blue flash inside the quartz tube. Apparently, the presence of this plasma blue flash is required for obtaining graphene flakes. The synthesized graphene was characterized by different techniques, showing the presence of non-oxidized graphene with high purity.
关键词： Chemical Vapor Deposition,Raman Spectroscopy,AFM,Plasma-Enhanced,Graphene Flakes
更新于2025-09-04 15:30:14