title: Tuning the band gap in silicene by oxidation.
abstract: 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 √13 × √13, 4 × 4, and 2√3 × 2√3 silicene layers. The Si-O-Si bonds are the most energy-favored species formed on √13 × √13, 4 × 4, and 2√3 × 2√3 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.
authors.affiliation: Institute for Superconducting and Electronic Materials (ISEM), University of Wollongong , Wollongong, New South Wales 2525, Australia.
authors.forename: Yi
authors.initials: Y
authors.lastname: Du
authors.forename: Jincheng
authors.initials: J
authors.lastname: Zhuang
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Liu
authors.forename: Xun
authors.initials: X
authors.lastname: Xu
authors.forename: Stefan
authors.initials: S
authors.lastname: Eilers
authors.forename: Kehui
authors.initials: K
authors.lastname: Wu
authors.forename: Peng
authors.initials: P
authors.lastname: Cheng
authors.forename: Jijun
authors.initials: J
authors.lastname: Zhao
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Pi
authors.forename: Khay Wai
authors.initials: KW
authors.lastname: See
authors.forename: Germanas
authors.initials: G
authors.lastname: Peleckis
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Wang
authors.forename: Shi Xue
authors.initials: SX
authors.lastname: Dou
keywords: DFT calculation; STM; band gap; oxidation; silicene