TY - JOUR
T1 - Chemical Vapor Deposition Synthesis of MoS2 Layers from the Direct Sulfidation of MoO3 Surfaces Using Reactive Molecular Dynamics Simulations
AU - Hong, Sungwook
AU - Sheng, Chunyang
AU - Krishnamoorthy, Aravind
AU - Rajak, Pankaj
AU - Tiwari, Subodh
AU - Nomura, Ken Ichi
AU - Misawa, Masaaki
AU - Shimojo, Fuyuki
AU - Kalia, Rajiv K.
AU - Nakano, Aiichiro
AU - Vashishta, Priya
N1 - Funding Information:
This work was supported as part of the Computational Materials Sciences Program funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award Number DE-SC00014607. The simulations were performed at the Argonne Leadership Computing Facility under the DOE INCITE program and at the Center for High Performance Computing of the University of Southern California.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/4/5
Y1 - 2018/4/5
N2 - Atomically thin MoS2 layer, a promising transition metal dichalcogenide (TMDC) material, has great potential for application in next-generation electronic and optoelectronic devices. Chemical vapor deposition (CVD) is the most effective technique for the synthesis of high-quality MoS2 layers. During CVD synthesis, monolayered MoS2 is generally synthesized by sulfidation of MoO3. Although qualitative reaction mechanisms for the sulfidation of MoO3 have been investigated by previous studies, the detailed reaction processes, including atomic-scale reaction pathways and growth kinetics, have yet to be fully understood. Here, we present quantum-mechanically informed and validated reactive molecular dynamics simulations of the direct sulfidation of MoO3 surfaces using S2 gas precursors. Our work clarifies the reaction mechanisms and kinetics of the sulfidation of MoO3 surfaces as follows: the reduction and sulfidation of MoO3 surfaces occur primarily at O-termination sites, followed by unsaturated Mo sites; these local reaction processes lead to nonuniform MoOxSy surface structures during the CVD process. After annealing the MoOxSy samples, the crystallized surface structures contain voids, and three different types of local surface complexes (MoOx, MoOxSy, and MoS2-like surface regions), depending on the fraction of S ingredients on the MoOxSy surface. These results, which have been validated by our reactive quantum molecular dynamics simulations and previous experimental results, provide valuable chemical insights into the CVD synthesis of large-scale and defect-free MoS2 layers and other layered TMDC materials.
AB - Atomically thin MoS2 layer, a promising transition metal dichalcogenide (TMDC) material, has great potential for application in next-generation electronic and optoelectronic devices. Chemical vapor deposition (CVD) is the most effective technique for the synthesis of high-quality MoS2 layers. During CVD synthesis, monolayered MoS2 is generally synthesized by sulfidation of MoO3. Although qualitative reaction mechanisms for the sulfidation of MoO3 have been investigated by previous studies, the detailed reaction processes, including atomic-scale reaction pathways and growth kinetics, have yet to be fully understood. Here, we present quantum-mechanically informed and validated reactive molecular dynamics simulations of the direct sulfidation of MoO3 surfaces using S2 gas precursors. Our work clarifies the reaction mechanisms and kinetics of the sulfidation of MoO3 surfaces as follows: the reduction and sulfidation of MoO3 surfaces occur primarily at O-termination sites, followed by unsaturated Mo sites; these local reaction processes lead to nonuniform MoOxSy surface structures during the CVD process. After annealing the MoOxSy samples, the crystallized surface structures contain voids, and three different types of local surface complexes (MoOx, MoOxSy, and MoS2-like surface regions), depending on the fraction of S ingredients on the MoOxSy surface. These results, which have been validated by our reactive quantum molecular dynamics simulations and previous experimental results, provide valuable chemical insights into the CVD synthesis of large-scale and defect-free MoS2 layers and other layered TMDC materials.
UR - http://www.scopus.com/inward/record.url?scp=85045025537&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85045025537&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.7b12035
DO - 10.1021/acs.jpcc.7b12035
M3 - Article
AN - SCOPUS:85045025537
VL - 122
SP - 7494
EP - 7503
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 13
ER -