Local charge states in hexagonal boron nitride with Stone–Wales defects

Abstract

A Stone-Wales (SW) defect is the simplest topological defect in graphene-like materials and can be potentially employed to design electronic devices . In this paper, we have systematically investigated the formation, structural, and electronic properties of the neutral and charged SW defects in hexagonal boron nitride (BN) using first-principles calculations. The transition states and energy barrier for the formation of SW defects demonstrate that the defected BN is stable. Our calculations show that there are two in-gap defect levels, which originate from the asymmetrical pentagon-heptagon pairs. The local defect configurations and electronic properties are sensitive to their charge states induced by the defect levels. The electronic band structures show that the negative and positive charged defects are mainly determined by shifting the conduction band minimum (CBM) and valence band maximum (VBM) respectively, and the SW-defected BN can realize -1 and +1 spin-polarized charge states. The effects of carbon (C) substitution on neutral and charged SW-defected BN have also been studied. Our results indicate that the C substitution of B in BN is in favour of the formation of SW defects. Structural and electronic calculations show rich charge-dependent properties of C substitutions in SW-defected BN, thus our theoretical study is important for various applications in the design of BN nanostructure-based devices.

Failure in Two-Dimensional Materials: Defect Sensitivity and Failure Criteria

“…The S-W defects were also found in other 2D materials such as boronitrene, transition metal dichalcogenides, and phosphorene [8,9,[61][62][63]. In boronitrene, like in graphene, an S-W defect is made by the 90 deg rotation of two adjacent B-and N-atoms around the midpoint of the bond connecting them [61] (see Fig. 3(b)), although the bond rotation results in the creation of two homoelemental bonds, which are energetically unfavorable.…”

“…2.7 Crack. A crack defect may appear in 2D materials after a pore was formed either spontaneously or with electron beam [61]. (c) Graphene randomly functionalized with methyl groups.…”

“…A single vacancy involves an elimination of a single atom, while a double vacancy requires a deletion of a pair of adjacent atoms. Note that double vacancies with an even number of missing atoms allow the complete saturation of dangling bonds, and therefore, they are thermodynamically favored over [34,47,54,61,74,88,89,92,[107][108][109]. single vacancy or triple vacancies with an odd number of missing atoms [52].…”

Structural Attributes and Photodynamics of Visible Spectrum Quantum Emitters in Hexagonal Boron Nitride

“…21 This type of reconstruction is not observed for mono-vacancy defects inside multi-layered h-BN which retain their three-fold symmetry. 48 This hints at a connection between the low dimensionality of h-BN to quantum features 49 These comprise a family of defects which also the complex 21 53 We can now link the angular multiplicity we have seen on perimeters where emitters are clustered ( Fig. 1h/1g) as another hint to the presence of Stone-Wales defects or a grain-boundary effect.…”

Ångström-Scale, Atomically Thin 2D Materials for Corrosion Mitigation and Passivation

“…A Stone-Wales defect has low formation energy in graphene, and therefore such defects can easily be observed in graphene [113]. Conversely, contrary to theoretical predictions, Stone-Wales defects have not been found experimentally in hBN [114][115][116][117]. Various 2D material preparation techniques have been developed, which can be classified generally into two categories: top-down techniques (i.e., exfoliation via mechanical [19,[93][94][95], liquid [96,97] or chemical [98,99] means, electro-ablation [100]), and bottom-up techniques (i.e., atomic layer deposition (ALD) [101,102], pulsed laser deposition (PLD) [103,104], chemical vapor deposition (CVD) [105,106]).…”