Fabrication and evaluation of Moire-angle controlled bilayer graphene

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02602
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 29020:Thin film/surface and interfacial physical properties-related
• Research Institution: Kyushu University
• Principal Investigator: Tanaka Satoru 九州大学, 工学研究院, 教授 (80281640)
• Co-Investigator(Kenkyū-buntansha): 神田 晶申 筑波大学, 数理物質系, 教授 (30281637) ; 小森 文夫 東京工業大学, 物質理工学院, 研究員 (60170388) ; Anton V.Visikovs 九州大学, 工学研究院, 助教 (70449487)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: グラフェン / エピタキシー / 電子状態

Outline of Final Research Achievements

When two layers of graphene rotated in-plane (twist angle) are stacked, a twisted two-layer graphene (TBG) is obtained. In this study, TBGs with controlled twist angles were prepared using epitaxial graphene growth, exfoliation, and transfer techniques on a SiC substrate, and their electronic characteristics were investigated.
1. Twist angle control: Graphene grows epitaxially on SiC, so by aligning the edge faces of two SiC substrates, it becomes 0 ° TBG, and by stepping motor, angle control is performed in the range of 0.7 to 4.0 ° by 0.1 ° accuracy.
2. Using angle-resolved photoelectron spectroscopy (ARPES), electronic structures of TBGs were examined. The spectra were well matched with the electronic state calculation of each twist angle.

Free Research Field

表面物理

Academic Significance and Societal Importance of the Research Achievements

TBGは超伝導を始めとする様々なユニークな物性が発現する場として大きな注目を浴びており，将来のデバイス応用への期待も高い．現状ではミクロンスケールの小片サンプルを用いた研究が主であり，サンプル品質にばらつきがあり，整合性のよい結果が得られていない．ツイスト角度は特に制御が困難であることから，学術的な議論を妨げる要因となっている．本研究で得られた大面積で，かつツイスト角度を制御したTBGを用いることにより，物性探索の範囲が大きく拡がり，新たな物性の発見に繋がる可能性がある．