Energy-gap opening in a Bi110 nanoribbon induced by edge reconstruction.
Scanning tunnelling microscopy and spectroscopy experiments complemented by first-principles calculations have been conducted to study the electronic structure of 4 monolayer Bi(110) nanoribbons on epitaxial graphene on silicon carbide [4H-SiC(0001)]. In contrast with the semimetal property of elemental bismuth, an energy gap of 0.4 eV is measured at the centre of the Bi(110) nanoribbons. Edge reconstructions, which can facilitate the edge strain energy release, are found to be responsible for the band gap opening. The calculated density of states around the Fermi level are decreased quickly to zero from the terrace edge to the middle of a Bi(110) nanoribbon potentially signifying a spatial metal-to-semiconductor transition. This study opens new avenues for room-temperature bismuth nanoribbon-based electronic devices.
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
Jia-Tao
JT
Sun
Han
H
Huang
Swee Liang
SL
Wong
H-J
HJ
Gao
Yuan Ping
YP
Feng
Andrew Thye Shen
AT
Wee
D001729:Bismuth / Q000737:chemistry*; D003080:Cold Temperature; D006108:Graphite / Q000737:chemistry; D016252:Microscopy, Scanning Tunneling / Q000379:methods; D008958:Models, Molecular; D049329:Nanostructures / Q000737:chemistry*; D012666:Semiconductors; D013057:Spectrum Analysis / Q000379:methods
D006108:Graphite; D001729:Bismuth