期刊
NANO LETTERS
卷 10, 期 8, 页码 3118-3122出版社
AMER CHEMICAL SOC
DOI: 10.1021/nl101884h
关键词
Topological insulator; bismuth selenide; nanoribbon; mechanical exfoliation; atomic force microscopy
类别
资金
- King Abdullah University of Science and Technology (KAUST) [KUS-11-001-12]
- KAUST [KUS-FI-033-02]
- NSF [DMR-0906027]
- Center of Probing the Nanoscale, Stanford University (NSF) [PHY-0425897]
- Direct For Mathematical & Physical Scien
- Division Of Physics [830228] Funding Source: National Science Foundation
Ultrathin topological insulator nanostructures, in which coupling between top and bottom surface states takes place, are of great intellectual and practical importance. Due to the weak van der Waals interaction between adjacent quintuple layers (QLs), the layered bismuth selenide (Bi2Se3), a single Dirac-cone topological insulator with a large bulk gap, can be exfoliated down to a few QLs. In this paper, we report the first controlled mechanical exfoliation of Bi2Se3 nanoribbons (>50 QLs) by an atomic force microscope (AFM) tip down to a single QL. Microwave impedance microscopy is employed to map out the local conductivity of such ultrathin nanoribbons, showing drastic difference in sheet resistance between 1-2 QLs and 4-5 QLs. Transport measurement carried out on an exfoliated (5 QLs) Bi2Se3 device shows nonmetallic temperature dependence of resistance, in sharp contrast to the metallic behavior seen in thick (>50 QLs) ribbons. These AFM-exfoliated thin nanoribbons afford interesting candidates for studying the transition from quantum spin Hall surface to edge states.
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