Point defects in epitaxial silicene on Ag(111) surfaces

Abstract

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

Computer Test of a New Silicene Anode for Lithium‐Ion Batteries

“…[34] It means that there would be one defect in every 2 nm 2 area. The estimated concentrations of mono-and bivacancies in silicene obtained on a metal substrate (Ag(111)) can be quite high such as 4.4 × 10 13 cm À 2 and 5.0 × 10 13 cm À 2 , respectively.…”

“…The estimated concentrations of mono-and bivacancies in silicene obtained on a metal substrate (Ag(111)) can be quite high such as 4.4 × 10 13 cm À 2 and 5.0 × 10 13 cm À 2 , respectively. [34] It means that there would be one defect in every 2 nm 2 area. The large concentration of point defects together 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 with easy diffusion and coalescence of vacancy defects nicely explains a lower stability of silicene in experiments.…”

Oxidation Behaviors of Two‐dimensional Metal Chalcogenides

“…In experiments, defects are quite common in 2D materials, such as self‐interstitials, vacancies, and grain boundaries, which are significant for the material's properties . For example, point defects, antisite defects, dislocations and vacancy complexes are commonly observed in graphene, silicone and TMDs, and they can lead to modification of the oxidation behaviors and hence change the physical and chemical properties of 2D materials …”

Electronic and magnetic properties of graphene, silicene and germanene with varying vacancy concentration

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The striking similarity among graphene, silicene and germanene arises from the fact that carbon, silicon and germanium belong to the same group in the periodic table of elements. However, the larger atomic radii of silicon and germanium promote sp 3 hybridization in silicene and germanene, while sp 2 hybridization is more favorable in graphene.…”