Van der Waals Growth of Thin TaS₂on Layered Substrates by Chemical Vapor Transport Technique

Abstract

Thin TaS 2 has been prepared by the van der Waals growth technique coupled with the chemical vapor transport technique using the I 2 agent. Hexagonal boron nitride (h-BN) and mica, which have layered crystal structures, were used as substrate materials. Thin TaS 2 was grown on layered substrates sealed in a quartz ampoule. A high-resolution X-ray diffractometer with a four-crystal monochrometer revealed that very thin 2H-TaS 2 film was grown on the surface of the Ag/BN substrate at 300 C, where Ag was evaporated on the h-BN substrate surface prior to the film growth. As for the mica substrate, very thin 2H-TaS 2 was grown on the substrates with and without Ag modification.

Chemical Vapor Transport Reactions for Synthesizing Layered Materials and Their 2D Counterparts

“…From this point of view, source materials and the mineralizer can be regarded as the most decisive factors in the growth of TMD crystals. Thereafter, the reaction conditions could be optimized case by case, typically in an empirical way, and some representative reactions are summarized in Table 1 …”

“…However, due to interfaces and defects of the exfoliated nanoscale flakes, the electronic properties of the prepared films are typically affected to some extent. Alternatively, direct synthesis of large‐scale thin films would be more suitable for electronic applications . Particularly, the atomically thin 2D TMD films are desired because of their thickness‐dependent properties.…”

Atomic‐Scale Edge Morphology, Stability, and Oxidation of Single‐Layer 2H‐TaS2

“…The oxidation of 2H-TaS 2 may thus proceed differently than that of 2H-MoS 2 . Available experimental observations suggested that TaS 2 interacts strongly with oxygen; Enomoto et al pointed out that top layer of thin 2H-TaS 2 prepared by van der Waals growth on the surface of the Ag/BN substrate at 300°C oxidized in air, [8] 2H-TaS 2 nanosheets prepared by electrochemical lithium intercalation showed surface oxidation after synthesis [57] and surface oxidation hampered expected electrocatalytic performance of the 2H-TaS 2 catalyst. [20] In fact, traces of oxidation were found even on freshly exfoliated TaS 2 flakes inserted into XPS chamber within 2 min after exfoliation.…”

Aerosol‐Assisted Chemical Vapor Deposition of NbS2 and TaS2 Thin Films from Pentakis(dimethylamido)metal Complexes and 2‐Methylpropanethiol

“…[13] It was found that reaction of [14,15] To the best of our knowledge, this paper represents the first thin film growth of TaS 2 by CVD and a novel aerosolassisted (AA)CVD route to MS 2 (M = Nb, Ta) from [M(NMe 2 ) 5 ] and tBuSH. Different and unique morphologies of films can be obtained by AACVD due to the influence of the solvent on the deposition, which could potentially lead to improved properties.…”

“…However, there are only limited reports of thin film formation of either NbS 2 or TaS 2 . [3,[10][11][12][13][14][15] Physical deposition of NbS 2 films has been achieved by dipping the substrate into a NbS 2 powder layer, lying at the interface between water and an organic solvent. [5,10] This produced films with the basal planes parallel to the substrate's surface.…”