2,890 research outputs found
The effect of crystal plane of Cu on the decision of stacking angle for bilayer graphene
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Synthesis of Small-angle Twisted Bilayer Graphene on Atomic-stepped Copper Surface by Chemical Vapor Deposition
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Rotation of Graphene on Cu during Chemical Vapor Deposition and Its Application to Control the Stacking Angle of Bilayer Graphene
No full text© 2022 American Chemical Society. All rights reserved.Control of the stacking angle (θS) of bilayer graphene (BLG) is essential for fundamental studies and applications of BLG. Especially, the use of chemical vapor deposition (CVD) to grow high-quality BLG requires this control, but methods to achieve it are not available. Here, we found that graphene rotates during the CVD process, and this action can be exploited as a new strategy to control θS. The rotation of graphene was revealed by the population changes of AB-stacked BLG and 30°-twisted BLG upon the growth time change; this change can only be explained by rotation of graphene. The rotation is largely affected by the edge state of graphene which can be tuned by growth temperature. The rotation was observed through experimental results combined with theoretical calculation. The rotation can be blocked or accelerated by controlling the growth temperature, by which highly selective growth of AB-stacked BLG or 30°-twisted BLG can be achieved.11Nsciescopu
Supplemental material for Subacute Transplantation of Native and Genetically Engineered Neural Progenitors Seeded on Microsphere Scaffolds Promote Repair and Functional Recovery After Traumatic Brain Injury
No full textSupplemental Material for Subacute Transplantation of Native and Genetically Engineered Neural Progenitors Seeded on Microsphere Scaffolds Promote Repair and Functional Recovery After Traumatic Brain Injury by Nolan B. Skop, Sweta Singh, Henri Antikainen, Chaitali Saqcena, Frances Calderon, Deborah E. Rothbard, Cheul H. Cho, Chirag D. Gandhi, Steven W. Levison and Radek Dobrowolski in ASN Neuro</p
Synthesis of bilayer graphene with controlled stacking order on Cu catalyst by chemical vapor deposition
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Exfoliated Graphite Electrodes for Organic Single Crystal Field Effect Transistor Device
No full textIn this work, exfoliated graphite was used as an electrode for organic single-crystal field-effect transistor (FET) devices, and the electrode performance was demonstrated. The reduced rigidity of exfoliated graphite allows good physical contact with organic single crystals in various morphologies. Because the work function of graphite matches well the HOMO energy level of most p-type organic molecules or the LUMO level of some n-type molecules, efficient charge injection from graphite electrodes to organic crystals is expected to result in high device performance. Indeed, the rubrene single-crystal FET devices fabricated using graphite electrodes exhibit high mobility (average of 2.38 cm2/V·s) with low threshold voltage and a high on/off current ratio. This is comparable to the FET devices that we fabricated using gold electrodes. Moreover, the graphite electrode devices of phenothiazine, C60, and PTCDA crystals also exhibited similar or improved device performance compared to devices with conventional metal electrodes. Another advantage of using graphite is the availability of chemical and physical treatments by which the work function of graphite can be tuned to a certain degree. We demonstrated improved performance of picene single-crystal FET devices employing oxygen-plasma-treated graphite electrodes. The work function change of graphite upon oxygen-plasma treatment was confirmed using Kelvin probe measurements. We thus confirmed that the improved device performance was achieved by a reduced charge injection barrier when the oxygen-plasma-treated graphite electrode was used. These results indicate that exfoliated graphite should be considered a potential candidate electrode material for organic crystal devices.11Nsciescopu
Correlation study between crystal plane of copper catalyst and stacking order of bilayer graphene
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Selective synthesis of Bernal-stacked and 30o-twisted bilayer graphene on Cu(111) catalyst by chemical vapor deposition
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Transfer-Free, Large-Scale Growth of High-Quality Graphene on Insulating Substrate by Physical Contact of Copper Foil
No full textHigh-quality, large-area, single-layer graphene was directly grown on top of a quartz substrate by a low-pressure chemical vapor deposition (CVD) process using Cu vapor as a catalyst. In this process, continuous generation and supply of highly concentrated Cu vapor is the key to the growth of largescale, high-quality graphene. It was achieved by direct physical contact, or "touch-down," of a Cu foil with an underlying sacrificial SiO2/Si substrate, and the target quartz substrate was placed on top of the Cu foil, eventually having a quartz/Cu/SiO2/Si sandwich structure. To establish the reaction mechanism, a test growth was performed without the quartz substrate, which revealed that Cu is diffused through the SiO2 layer of the sacrificial SiO2/Si substrate to form liquid-phase Cu-Si alloy that emits massive Cu vapor. This Cu vapor catalyzes thermal decomposition of supplied CH4 gas.11Nsciescopu
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