Formation of MoS₂ Inorganic Fullerenes (IFs) by the Reaction of MoO₃ Nanobelts and S

Abstract

The reaction of MoO3 and S at temperatures higher than 300 degrees C in an argon atmosphere provides a convenient and effective method for the synthesis of MoS2 nanocrystalline substances. MoS2 nanotubes and fullerene-like nanoparticles have been obtained by the reaction at 850 degrees C under well-controlled conditions. The influences of reaction temperature and duration were carefully investigated in this paper. All of the nanostructures were characterized by Xray powder diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). A stepwise reaction model and rolling mechanism were proposed based on the experimental results.

Large‐Area Vapor‐Phase Growth and Characterization of MoS2 Atomic Layers on a SiO2 Substrate

“…Electron hopping among grains would significantly decrease the mobilities in MoS 2 . 22,23 In addition, other defects including cationic vacancies, dislocation and adsorption-induced doping effect in the MoS 2 are also possible reasons for the low mobilities, which are always observed in CVD-prepared two dimensional materials like graphene. 14 The mobility could be significantly improved by annealing the as-prepared samples, 8,20 using local top-gate with high-κ dielectric, 8,21 and optimizing the growth conditions.…”

Synthesis of Monolayer MoS2 by CVD Approach

“…After the temperature was kept at 850 °C for 10 min, at such a high temperature, MoO 3 powder evaporated and reacts with sulfur vapor to form volatile suboxide MoO 3-x . [13] these suboxide compounds diffused to the substrate and further reacted with sulfur vapor to grow MoS 2 films [15] . Finally, the furnace was cooled down to room temperature naturally.…”

“…It has been reported that MoS 2 formed as the result of the stepwise reaction of substitution and reduction which lead to an intermediate product of MoO 3-x . [13,16] Although the growth dynamics of MoO 3-x and sulfur are still not fully understood, there are two possible channels for the surface growth that can be expected: (1) MoO 3-x species adsorb and diffuse on the substrate, reacting with S to form MoS 2 ; (2) MoO 3-x and sulfur react directly in the gas phase, and the resulting MoS 2 clusters adsorb, nucleate, and grow on the substrate [17] . In our experiment, the reaction process is described as follows.…”

“…Considering the fact that MoO 2 , the most common intermediate product, is one of the most stable oxides of molybdenum, we can assum the x=1. A possible stepwise reaction process of MoO 3 and S is given in equations (1) and (2) [13] . …”

“…In addition, bulk (or multilayer) MoS 2 exhibits relatively high in-plane carrier mobility comparable to that of crystalline silicon [7] as well as robust mechanical and chemical properties, which makes it an attractive material for making flexible electronic devices with high performance and long lifetime [3,8,9] . The current approaches for fabricating thin layers of MoS 2 are as follows, mechanical and liquid exfoliation [10,11] of bulk materials, physical vapor deposition [12] and chemical vapor deposition [13,14] . CVD is a direct bottom-up method for producing large-area uniform poly crystalline thin films.…”