Epitaxial growth of topological insulator Bi2Se3 film on Si(111) with atomically sharp interface |
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Authors: | Namrata Bansal Yong Seung Kim Eliav EdreyMatthew Brahlek Yoichi HoribeKeiko Iida Makoto TanimuraGuo-Hong Li Tian FengHang-Dong Lee Torgny GustafssonEva Andrei Seongshik Oh |
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Affiliation: | a Department of Electrical and Computer Engineering, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USAb Graphene Research Institute, Sejong University, Seoul 143-747, Republic of Koreac Department of Physics and Astronomy, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USAd Research Department, Nissan Arc, Ltd. Yokosuka, Kanagawa 237-0061, Japan |
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Abstract: | Atomically sharp epitaxial growth of Bi2Se3 films is achieved on Si(111) substrate with molecular beam epitaxy. Two-step growth process is found to be a key to achieve interfacial-layer-free epitaxial Bi2Se3 films on Si substrates. With a single-step high temperature growth, second phase clusters are formed at an early stage. On the other hand, with low temperature growth, the film tends to be disordered even in the absence of a second phase. With a low temperature initial growth followed by a high temperature growth, second-phase-free atomically sharp interface is obtained between Bi2Se3 and Si substrate, as verified by reflection high energy electron diffraction (RHEED), transmission electron microscopy (TEM) and X-ray diffraction. The lattice constant of Bi2Se3 is observed to relax to its bulk value during the first quintuple layer according to RHEED analysis, implying the absence of strain from the substrate. TEM shows a fully epitaxial structure of Bi2Se3 film down to the first quintuple layer without any second phase or an amorphous layer. |
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Keywords: | Topological insulators Molecular beam epitaxy Silicon Bismuth selenide Interface structure Transmission electron microscopy Reflection high energy electron diffraction |
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