Tuning the Band Gap in Silicene by Oxidation

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• 作者：Yi Du ; Jincheng Zhuang ; Hongsheng Liu ; Xun Xu ; Stefan Eilers ; Kehui Wu ; Peng Cheng ; Jijun Zhao ; Xiaodong Pi ; Khay Wai See ; Germanas Peleckis ; Xiaolin Wang ; Shi Xue Dou
• 刊名：ACS Nano
• 出版年：2014
• 出版时间：October 28, 2014
• 年：2014
• 卷：8
• 期：10
• 页码：10019-10025
• 全文大小：586K
• ISSN：1936-086X

文摘

Silicene monolayers grown on Ag(111) surfaces demonstrate a band gap that is tunable by oxygen adatoms from semimetallic to semiconducting type. With the use of low-temperature scanning tunneling microscopy, we find that the adsorption configurations and amounts of oxygen adatoms on the silicene surface are critical for band gap engineering, which is dominated by different buckled structures in 鈭?3 脳 鈭?3, 4 脳 4, and 2鈭? 脳 2鈭? silicene layers. The Si鈥揙鈥揝i bonds are the most energy-favored species formed on 鈭?3 脳 鈭?3, 4 脳 4, and 2鈭? 脳 2鈭? structures under oxidation, which is verified by in situ Raman spectroscopy as well as first-principles calculations. The silicene monolayers retain their structures when fully covered by oxygen adatoms. Our work demonstrates the feasibility of tuning the band gap of silicene with oxygen adatoms, which, in turn, expands the base of available two-dimensional electronic materials for devices with properties that is hardly achieved with graphene oxide.

Keywords:

silicene; oxidation; band gap; STM; DFT calculation