Controllable Growth of Few-Layer Niobium Disulfide by Atmospheric Pressure Chemical Vapor Deposition for Molecular Sensing

Abstract

Two-dimensional metallic NbS 2 has attracted increasing attentions due to its excellent properties. So far, the preparations of NbS 2 are mainly focused on the mechanical exfoliation and molecular beam epitaxial (MBE), both of which have limitations, such as, small lateral sizes (usually <1 µm), low yield, etc. Chemical vapor deposition (CVD) has been used to synthesize NbS 2 , but mainly depends on atomically flat substrates (e.g., graphene, h-BN) to grow thinner and larger sheets and the growth of NbS 2 on SiO 2 /Si is still challenging. In this contribution, NbS 2 single crystals with different layers are controllably synthesized. Few-layer NbS 2 single crystals from one layer to nine layers with several tens of micrometers lateral sizes (up to ∼20 µm) can be obtained by controlling hydrogen content in Ar/H 2 carrier gas, NaCl amount, the growth temperature and the growth time, which are much larger than that synthesized by the MBE route. Meanwhile, as-synthesized NbS 2 demonstrates higher sensitivity for probing trace amount of molecules than that of graphene, ascribed to the efficient charge transfer between NbS 2 and molecules.

Recent advances in non‐plasmonic surface‐enhanced Raman spectroscopy nanostructures for biomedical applications

“…(ii) Metallic transition-metal dichalcogenides: the use of metallic transition-metal dichalcogenides can meet this challenge as these materials possess abundant density of states near the Fermi level and high surface activity leading to efficient charge transfer with molecules adsorbed on their surface. 93 Niobium diselenide (NbSe2) is a typical 2D metallic transition-metal dichalcogenides, exhibiting a layer-dependent electronic structure. Large-area NbSe2 flakes from monolayers to fewlayers were prepared using an ambient pressure chemical vapor deposition route.…”

“…The use of metallic transition-metal dichalcogenides can meet this challenge as these materials possess abundant density of states near the Fermi level and high surface activity leading to efficient charge transfer with molecules adsorbed on their surface (Lv et al, 2019). Niobium diselenide (NbSe 2 ) is a typical 2D metallic transition-metal dichalcogenides, exhibiting a layer-dependent electronic structure.…”

Recent Advances in 2D Group VB Transition Metal Chalcogenides

“…In this work, the metallic nature of VS 2 nanosheets was also demonstrated by temperature-dependent electrical measurements and optical characterization. [33] Later, other 2D GVTMCs, including, VS 2 (H phase), [110] VSe 2 , [66,111,112] VTe 2 , [71] NbS 2 , [113,114] NbSe 2 , [115] NbTe 2 , [71] TaS 2 , [116] TaSe 2 , [117] TaTe 2 , [71] etc. were also successfully prepared by CVD method.…”

Noble Metal‐Free Surface‐Enhanced Raman Scattering Enhancement from Bandgap‐Controlled Graphene Quantum Dots

“…To understand the generality of GQD-induced SERS effect on other probe molecules, we have additionally performed the SERS measurement of CV and 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBI) with GQD-N18 under 532 nm laser excitations. Previous work reports that CV and TPBI are Raman probe molecules with different band structures and can be used to study the CT between SERS substrates and probe molecules [67,69] . Figure S6, Supporting Information shows the Raman spectra of CV and TPBI (both with 10 −4 m concentration) with plasma-synthesized GQD-N18.…”