Abstract
Silicene on metal silicides poses promise for direct integration of silicene into electronic devices. The details of the metal silicide-silicene interface, however, may have significant effects on the electronic properties. In this work, we investigate the electronic properties of silicene on NiSi2(111) and hydrogenated NiSi2(111) (H:NiSi2) substrates, as well as hydrogenated silicene (H:silicene) on a NiSi2(111) substrate, from first principles. The preferred Si surface termination of NiSi2 was determined through surface energy calculations, and the band structure and density of states (DOS) were calculated for the two-dimensional silicene and H:silicene layers. Hydrogenating NiSi2 lowered the binding energy between silicene and the substrate, resulting in partial decoupling of the electronic properties. Relaxed silicene on H:NiSi2 showed a small band gap opening of 0.14 eV. Silicene on H:NiSi2 also had a calculated electron effective mass of 0.08m0 and a Fermi velocity of 0.39 × 106 m/s, which are similar to the values for freestanding silicene. H:silicene on NiSi2 retained its indirect band structure and DOS compared to freestanding H:silicene. The band gap of H:silicene on NiSi2 was 1.97 eV which is similar to the freestanding H:silicene band gap of 1.99 eV. This results showed that hydrogenation may be a viable method for decoupling a silicene layer from a NiSi2(111) substrate to tune its electronic properties.
| Original language | English (US) |
|---|---|
| Article number | 133111 |
| Journal | Applied Physics Letters |
| Volume | 109 |
| Issue number | 13 |
| DOIs | |
| State | Published - Sep 26 2016 |
Funding
The authors would like to acknowledge helpful discussions with Badri Narayanan. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)