Exceptional optoelectronic properties of hydrogenated bilayer silicene

Bing Huang, Hui Xiong Deng, Hoonkyung Lee, Mina Yoon, Bobby G. Sumpter, Feng Liu, Sean C. Smith, Su Huai Wei

Research output: Contribution to journalArticlepeer-review

95 Scopus citations

Abstract

Silicon is arguably the best electronic material, but it is not a good optoelectronic material. By employing first-principles calculations and the cluster-expansion approach, we discover that hydrogenated bilayer silicene (BS) shows promising potential as a new kind of optoelectronic material. Most significantly, hydrogenation converts the intrinsic BS, a strongly indirect semiconductor, into a direct-gap semiconductor with a widely tunable band gap. At low hydrogen concentrations, four ground states of single- and doublesided hydrogenated BS are characterized by dipole-allowed direct (or quasidirect) band gaps in the desirable range from 1 to 1.5 eV, suitable for solar applications. At high hydrogen concentrations, three well-ordered double-sided hydrogenated BS structures exhibit direct (or quasidirect) band gaps in the color range of red, green, and blue, affording white light-emitting diodes. Our findings open opportunities to search for new silicon-based light-absorption and light-emitting materials for earth-abundant, highefficiency, optoelectronic applications.

Original languageEnglish
Article number021029
JournalPhysical Review X
Volume4
Issue number2
DOIs
StatePublished - 2014

Keywords

  • Computational physics
  • Condensed matter physics
  • Graphene

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