単結晶,大きな面積,折りたたみのない単層グラフェン
Meihui Wang1,2, Ming Huang1,3, Da Luo4
1Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, Republic of Korea.
Nature
|August 26, 2021
まとめ
研究者は 成長温度を制御することで グラフェンフィルムの折りたたみのような欠陥を防ぐことができました この方法により,高品質の折りたたみのないグラフェンを生成し,均一な電子特性を持ち,スケーラブルなアプリケーションに適しています.
科学分野:
- 材料科学
- ナノテクノロジー
- 表面科学
背景:
- 金属基板の化学蒸気堆積 (CVD) は,スケーラブルなグラフェン合成の鍵です.
- グラフェンフィルムにはしばしば粒子の境界,アデラー,折りたたみなどの不完全性があり,性能を低下させます.
- グラフェンの折りたたみについては,他の欠陥と比較してあまり研究されていません.
研究 の 目的:
- CVDの成長中のグラフェン折りの形成メカニズムを調査する.
- 大面積で高品質で折りたたみのないグラフェンフィルムを生産する条件を特定する.
- 再現可能でスケーラブルなグラフェン合成のためのCVDプロセスを最適化します.
主な方法:
- 単一結晶のCu-Ni (111) フィルムにエチレンの前駆体を使用してグラフェンの成長.
- 初期成長温度を制御する.
- 冷却中の膜形態と欠陥形成の分析
- グラフェンフィールド効果トランジスタの製造と特徴付け
主要な成果:
- 成長の臨界温度は1030ケルビンで,その上では冷却時に折りたたみが生じます.
- 折りたたみは,Cu-Niフォイルのステップバッチングを通じて圧縮ストレスの解放によって引き起こされます.
- 成長温度を1,000〜1,030ケルビンの間に制限すると,折りたたみのない単結晶単層グラフェンが得られます.
- このフィルムは,平均流動性 (7.0 ± 1.0) ×103cm2/Vsで,高品質の輸送特性を有する.
- このプロセスは複数のフォイルで同時に成長し,フォイルの再利用を可能にします.
結論:
- CVDの成長温度を制御することは,グラフェンの折りたたみを防ぐために非常に重要です.
- 特定された温度窓は,高品質の,折りたたみのないグラフェンのスケーラブルな生産を可能にします.
- この方法は,グラフェンの均一な輸送特性により,電子アプリケーションの可能性を高めます.
関連する概念動画
02:42Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
02:37Metallic Solids
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
02:18Network Covalent Solids
Network covalent solids contain a three-dimensional network of covalently bonded atoms as found in the crystal structures of nonmetals like diamond, graphite, silicon, and some covalent compounds, such as silicon dioxide (sand) and silicon carbide (carborundum, the abrasive on sandpaper). Many minerals have networks of covalent bonds.
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
01:21Polymer Classification: Crystallinity
Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
01:18Unit Cells
A crystal's internal structure is an orderly array of atoms, ions, or molecules, and the details of this array significantly influence the solid's properties. In a crystal, periodically repeating 'structural motifs' - which could be atoms, molecules, or groups thereof - create a 'space lattice.' This is essentially a three-dimensional, infinite array of points, each surrounded by its neighbors in an identical way, forming the basic structure of the crystal.A 'unit cell' is a theoretical...
01:25Imperfections in Crystal Structure: Point, Line and Plane Defects
A perfect crystal, in theory, has a uniform structure with the same unit cell and lattice points throughout. However, any deviation from this periodic arrangement is known as an imperfection or defect. These defects can be categorized into three types: point, line, and plane defects.Point defects occur when there is a deviation from the ideal due to missing atoms, displaced atoms, or additional atoms. These imperfections might occur due to imperfect packing during crystallization or because of...