Electronic properties of hydrogenated silicene and germanene

Houssa, Michel; Scalise, Emilio; Sankaran, Kiroubanand; Pourtois, Geoffrey; Afanasʼev, Valeri; Stesmans, André

doi:10.1063/1.3595682

Cited by 438 publications

(340 citation statements)

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“…Due to strong spin-orbit coupling (SOC), the quantum spin Hall effect may be observed in silicene in an experimentally accessible temperature regime [13]. A tunable band gap can be opened up to about 4 eV in silicene by applying a perpendicular electric field [21][22] and by hydrogenation [23][24][25][26], halogenation [27][28], and oxidation [29][30]. Owing to these excellent properties and easy integration into the current Si-based semiconductor technology, silicene holds great promise for future applications in nanoelectronic devices.…”

Section: Introductionmentioning

confidence: 99%

Point defects in epitaxial silicene on Ag(111) surfaces

Liu

Feng

et al. 2016

2D Mater.

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Silicene, a counterpart of graphene, has achieved rapid development due to its exotic electronic properties and excellent compatibility with the mature silicon-based semiconductor technology. Its low room-temperature mobility of ~100 cm2 V−1 s−1, however, inhibits device applications such as in field-effect transistors. Generally, defects and grain boundaries would act as scattering centers and thus reduce the carrier mobility. In this paper, the morphologies of various point defects in epitaxial silicene on Ag(111) surfaces have been systematically investigated using first-principles calculations combined with experimental scanning tunneling microscope (STM) observations. The STM signatures for various defects in epitaxial silicene on Ag(111) surface are identified. In particular, the formation energies of point defects in Ag(111)-supported silicene sheets show an interesting dependence on the superstructures, which, in turn, may have implications for controlling the defect density during the synthesis of silicene. Through estimating the concentrations of various point defects in different silicene superstructures, the mystery of the defective appearance of $\sqrt{13}\times \sqrt{13}$ and $2\sqrt{3}\times 2\sqrt{3}$ silicene in experiments is revealed, and 4 x 4 silicene sheet is thought to be the most suitable structure for future device applications. , however, inhibits device applications such as in field-effect transistors. Generally, defects and grain boundaries would act as scattering centers and thus reduce the carrier mobility. In this paper, the morphologies of various point defects in epitaxial silicene on Ag(111) surfaces have been systematically investigated using first-principles calculations combined with experimental scanning tunneling microscope (STM) observations. The STM signatures for various defects in epitaxial silicene on Ag(111) surface are identified. In particular, the formation energies of point defects in Ag(111)-supported silicene sheets show an interesting dependence on the superstructures, which, in turn, may have implications for controlling the defect density during the synthesis of silicene. Through estimating the concentrations of various point defects in different silicene superstructures, the mystery of the defective appearance of 13 × 13 and 2 3 ×2 3 silicene in experiments is revealed, and 4×4 silicene sheet is thought to be the most suitable structure for future device applications. Disciplines Engineering | Physical Sciences and Mathematics2

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Section: Introductionmentioning

confidence: 99%

Point defects in epitaxial silicene on Ag(111) surfaces

Liu

Feng

et al. 2016

2D Mater.

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“…Among numerous chemical methods, hydrogenation has been demonstrated to be one of the most powerful approaches to tune the electronic properties of 2D materials. For example, it has been demonstrated that hydrogenation can open sizable band gaps in graphene [40][41][42], graphyne [43], and single-layer silicene [44][45][46]. However, none of these hydrogenated structures reported to date is suitable for solar applications; in particular, there may be a strong phase separation in the ground states of these materials.…”

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confidence: 99%

Exceptional Optoelectronic Properties of Hydrogenated Bilayer Silicene

et al. 2014

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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.

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“…In the so-called boat configuration the H atoms alternate in pairs instead, which slightly increases the unit cell size. The latter has been shown to be notably less stable than the chair configuration in the case of graphane [29], nevertheless the boat configuration of silicane and germanane has been found to be stable [25] which is important to bear in mind.…”

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confidence: 99%