Chiral vectors-tunable electronic property of MoS2 nanotubes

Abstract

The chirality plays a critical role in affecting the electronic property, wherein the armchair nanotube exhibits the indirect-band-gap and zigzag with direct-band-gap. The MoS 2 NTs with lower chiral vectors occupy the relatively higher carrier mobility for both armchair and zigzag types. The similarity of lattice parameters and formation energy implies a potential possibility of transition between two types of NTs with low index chiral vectors. a b s t r a c tIt has been demonstrated that the mechanical and electronic properties of materials change significantly when the external dimension are confined to the nanoscale. Consequently, one-dimensional (1D) transition-metal dichalcogenide (TMDC) nanotubes (NTs), obtained from scrolling 2D TMDC, have attracted much attentions because of their intriguing properties and the chirality plays a key role in affecting the electronic properties. Taking the amount of speculations on the mechanism and the increasing needs for better device design and performance control, understanding the effect of chirality on the electronic properties is timely and relevant. Here, MoS 2 NTs are comprehensively studied by first-principles calculations. The results show that the armchair (6 rchr14) exhibits the indirect-band-gap and zigzag (10 r chr20) with direct-band-gap. Moreover, the carrier mobility is enhanced with the decrease of radial length, in accord with the smaller effective mass of hole and electron for both types NTs. Finally, the formation energy showed that the smaller the radial diameters is, the harder the NTs is to form. Moreover, the similarity of lattice parameters and formation energy implies a potential possibility of transition between two types of NTs with low index chiral vectors, such as ANT(6,6)/ZNT(10,0).

Torsional strain engineering of transition metal dichalcogenide nanotubes: an ab initio study

“…bulk TMDs [102]. In view of this and the tremendously larger cost associated with hybrids, PBE has been the functional of choice for TMD nanotubes [40,44,45,[47][48][49][50][52][53][54][55]. Note that the incorporation of spin-orbit coupling causes relatively minor modifications to the band structure [5], which is why it has been neglected here.…”

“…This manifests itself into varying electronic properties encompassing semiconducting [31,32], metallic [33,34], and superconducting [35,36]. Notably, a number of mechanisms have been found to tune/tailor these properties, including chirality/radius [31,32,[37][38][39][40][41][42][43][44][45], defects [46,47], temperature [35,36], electric field [48,49], and mechanical deformation [50][51][52][53][54][55][56]. This makes TMD nanotubes ideally suited for a number of technological applications, including nanoelectromechanical devices [56][57][58], photodetectors [59][60][61], mechanical sensors [51,62,63], biosensors [64], and superconductive materials [35,36].…”

Sorting Transition-Metal Dichalcogenide Nanotubes by Centrifugation

“…5 Additionally, theoretical studies suggested that small diameter nanotubes have a onedimensional band structure due to quantum confinement, 10 and we can tune the bandgap and enhance carrier mobility. 11 However, the one-dimensional nature of TMDC nanotubes has not been revealed yet because of difficulties in the synthesis of thin nanotubes with a uniform diameter and wall number. 12−15 It is important to develop a technique to prepare nanotubes with thin diameters in a relatively small distribution.…”

Water Freezing in MoS2 Nanotubes

“…Analogous to CNTs, these one-dimensional transition-metal dichalcogenide (TMDC) nanotubes have attracted much attention and prompted numerous studies because of their potential as lubricants and for optoelectronic devices and electrochemical hydrogen storage . MoS 2 NTs consist of a middle-Mo layer sandwiched between two S layers and can be classified as armchair or zigzag NTs based on their chiral vectors . Recently, a multilayer two-dimensional water structure confined in MoS 2 nanocavities has been reported .…”

“…21 MoS 2 NTs consist of a middle-Mo layer sandwiched between two S layers and can be classified as armchair or zigzag NTs based on their chiral vectors. 22 Recently, a multilayer two-dimensional water structure confined in MoS 2 nanocavities has been reported. 23 Unlike graphene, water spontaneously fills the region sandwiched by two MoS 2 nanosheets at ambient conditions to form planar multilayered water structures.…”