Epitaxial growth of topological insulator Bi2Se3 film on Si(111) with atomically sharp interface

THIN SOLID FILMS

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Article

Bansal, Namrata²  Kim, Yong Seung³  Edrey, Eliav¹  Brahlek, Matthew¹  Horibe, Yoichi¹  IidaD, Keiko⁴  Tanimura, Makoto⁴  Li, Guo-Hong¹  Feng, Tian¹  Lee, Hang-Dong¹  Gustafsson, Torgny¹  Andrei, Eva Y.¹  Oh, Seongshik¹ 

[1] Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA

[2] Rutgers State Univ, Dept Elect & Comp Engn, Piscataway, NJ 08854 USA

[3] Sejong Univ, Graphene Res Inst, Seoul 143747, South Korea

[4] Nissan Arc Ltd, Dept Res, Yokosuka, Kanagawa 2370061, Japan

关键词: Topological insulators;    Molecular beam epitaxy;    Silicon;    Bismuth selenide;    Interface structure;    Transmission electron microscopy;    Reflection high energy electron diffraction;   

DOI  :  10.1016/j.tsf.2011.07.033

来源: Elsevier

【 摘 要 】

Atomically sharp 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. (C) 2011 Elsevier B.V. All rights reserved.

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