Restoring pristine Bi2Se3 surfaces with an effective Se decapping process

作     者：Jixia Dai Wenbo Wang Matthew Brahlek Nikesh Koirala Maryam Salehi Seongshik Oh Weida Wu 

作者机构：Department of Physics and Astronomy Rutgers University Piscataway NJ 08854 USA 

出 版 物：《Nano Research》 (纳米研究（英文版）)

年 卷 期：2015年第8卷第4期

页      面：1222-1228页

核心收录：

学科分类：081702[工学-化学工艺] 0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 0817[工学-化学工程与技术] 080401[工学-精密仪器及机械] 0804[工学-仪器科学与技术] 0805[工学-材料科学与工程（可授工学、理学学位）] 0803[工学-光学工程] 0702[理学-物理学] 

基　　金：support by NSF 美国国家科学基金 ONR 

主　　题：topological insulator molecular beam epitaxy scanning tunnelingmicroscopy 

摘      要：High quality thin films of topological insulators （TI） such as Bi2Se3 have been successfully synthesized by molecular beam epitaxy （MBE）. Although the surface of MBE films can be protected by capping with inert materials such as amorphous Se, restoring an atomically clean pristine surface after decapping has never been demonstrated, which prevents in-depth investigations of the intrinsic properties of TI thin films with ex situ tools. Using high resolution scanning tunneling microscopy/spectroscopy （STM/STS）, we demonstrate a simple and highly reproducible Se decapping method that allows recovery of the pristine surface of extremely high quality Bi2Se3 thin films grown and capped with Se in a separate MBE system then exposed to the atmosphere during transfer into the STM system. The crucial step of our decapping process is the removal of the surface contaminants on top of amorphous Se before thermal desorption of Se at a mild temperature （-210 ~C）. This effective Se decapping process opens up the possibility of ex situ characterizations of pristine surfaces of interesting selenide materials and beyond using cutting-edge techniques.