Defects in Silicene: Vacancy Clusters, Extended Line Defects and Di-adatoms

Journal of Nanomaterials

Han

Zhang

et al. 2015

First principle calculations based on density functional theory with the generalized gradient approximation were carried out to investigate the energetic and electronic properties of carbon and boron nitride double-wall hetero-nanotubes (C/BN-DWHNTs) with different chirality and size, including an armchair (n,n) carbon nanotube (CNT) enclosed in (m,m) boron nitride nanotube (BNNT) and a zigzag (n, 0) CNT enclosed in (m, 0) BNNT. The electronic structure of these DWHNTs under a transverse electric field was also investigated. The ability to tune the band gap with changing the intertube distance (di) and imposing an external electric field (F) of zigzag DWHNTs provides the possibility for future electronic and electrooptic nanodevice applications.

Section: Calculation Methodsmentioning

confidence: 99%

Tuning Electronic Structures of BN and C Double‐Wall Hetero‐Nanotubes

Journal of Nanomaterials

Han

Zhang

et al. 2015

“…However, they did not investigate the electronic and magnetic properties of silicene with vacancy clusters and extended line defects. 42 Monovacancies could be carrier scattering centers in germanene. These scattering centers decreased the current up to 42% in defective germanene compared with pristine germanene.…”

Section: Introductionmentioning

confidence: 99%

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

Ali

et al. 2017

AIP Advances

The experimental realization of two-dimensional materials such as graphene, silicene and germanene has attracted incredible interest ranging from understanding their physical properties to device applications. During the fabrication and processing of these two-dimensional materials, structural defects such as vacancies may be produced. In this work we have systemically investigated the formation energies, electronic and magnetic properties of graphene, silicene and germanene with vacancies in the framework of spin polarized density functional theory. It is found that the magnetic moment of graphene and silicene with vacancies decreases with the increase in the concentration of vacancies. However, germanene remains non-magnetic irrespective of the vacancy concentration. Low-buckled silicene and germanene with vacancies may possess remarkable band gaps, in contrast to planar graphene with vacancies. With the formation of vacancies silicene and germanene demonstrate a transition from semimetal to semiconductor, while graphene turns to be metallic.

“…Therefore, a deep understanding of defects is highly desirable before fabrication of large-scale high-quality silicene layers for device applications. Recently, several typical point defects, including Stone-Wales (SW) rotation, single and double vacancies (SVs and DVs), and silicon adatoms in freestanding silicene have been systematically investigated using density functional theory (DFT) calculations, focusing on the geometries, energetics, and effects on electronic properties [40][41][42][43][44][45][46][47][48][49][50]. It was found that the SWs and DVs may induce small gaps in silicene, while the SV defect leads to a semimetallic-to-metallic transition in silicene.…”

Section: Introductionmentioning

confidence: 99%

Point defects in epitaxial silicene on Ag(111) surfaces

Feng

et al. 2016

2D Mater.

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