Defect Healing in Layered Materials: A Machine Learning-Assisted Characterization of MoS2 Crystal Phases.

Monolayer MoS2 is an outstanding candidate for a next-generation semiconducting material because of its exceptional physical, chemical, and mechanical properties. To make this promising layered material applicable to nanostructured electronic applications, synthesis of a highly crystalline MoS2 monolayer is vitally important. Among different types of synthesis methods, chemical vapor deposition (CVD) is the most practical way to synthesize few- or mono-layer MoS2 on the target substrate owing to its simplicity and scalability. However, synthesis of a highly crystalline MoS2 layer remains elusive. This is because of the number of grains and defects unavoidably generated during CVD synthesis. Here, we perform multimillion-atom reactive molecular dynamics (RMD) simulations to identify an origin of the grain growth, migration, and defect healing process on a CVD-grown MoS2 monolayer. RMD results reveal that grain boundaries could be successfully repaired by multiple heat treatments. Our work proposes a new way of controlling the grain growth and migration on a CVD-grown MoS2 monolayer.

[1]  Blöchl,et al.  Projector augmented-wave method. , 1994, Physical review. B, Condensed matter.

[2]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[3]  G. Kresse,et al.  Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set , 1996 .

[4]  Kresse,et al.  Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. , 1996, Physical review. B, Condensed matter.

[5]  G. Henkelman,et al.  A climbing image nudged elastic band method for finding saddle points and minimum energy paths , 2000 .

[6]  A. V. Duin,et al.  ReaxFF: A Reactive Force Field for Hydrocarbons , 2001 .

[7]  S. Louie,et al.  Energy gaps in graphene nanoribbons. , 2006, Physical Review Letters.

[8]  Kevin T. Turner,et al.  Friction laws at the nanoscale , 2009, Nature.

[9]  J. Shan,et al.  Atomically thin MoS₂: a new direct-gap semiconductor. , 2010, Physical review letters.

[10]  Jianguo Wang,et al.  Theoretical Cluster Studies on the Catalytic Sulfidation of MoO3 , 2010 .

[11]  Hisato Yamaguchi,et al.  Photoluminescence from chemically exfoliated MoS2. , 2011, Nano letters.

[12]  Lain‐Jong Li,et al.  Synthesis of Large‐Area MoS2 Atomic Layers with Chemical Vapor Deposition , 2012, Advanced materials.

[13]  A. Kis,et al.  Breakdown of high-performance monolayer MoS2 transistors. , 2012, ACS nano.

[14]  Qing Hua Wang,et al.  Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. , 2012, Nature nanotechnology.

[15]  P. Ajayan,et al.  Large Area Vapor Phase Growth and Characterization of MoS2 Atomic Layers on SiO2 Substrate , 2011, 1111.5072.

[16]  SUPARNA DUTTASINHA,et al.  Van der Waals heterostructures , 2013, Nature.

[17]  O. Yazyev,et al.  Polycrystalline graphene and other two-dimensional materials. , 2014, Nature nanotechnology.

[18]  Ying-Sheng Huang,et al.  Atomic mechanism of the semiconducting-to-metallic phase transition in single-layered MoS2. , 2014, Nature nanotechnology.

[19]  Rajeev Kumar,et al.  Transport properties of monolayer MoS2 grown by chemical vapor deposition. , 2014, Nano letters.

[20]  Qing Zhang,et al.  Few-layer MoS2: a promising layered semiconductor. , 2014, ACS nano.

[21]  S. Seal,et al.  Recent development in 2D materials beyond graphene , 2015 .

[22]  Haixin Chang,et al.  Synthesis of high quality two-dimensional materials via chemical vapor deposition , 2015, Chemical science.

[23]  S. Mahapatra,et al.  Effect of Line Defects on the Electrical Transport Properties of Monolayer MoS $_{\bf 2}$ Sheet , 2014, IEEE Transactions on Nanotechnology.

[24]  Sungjoo Lee,et al.  Size-tunable synthesis of monolayer MoS2 nanoparticles and their applications in non-volatile memory devices. , 2016, Nanoscale.

[25]  E. Kaxiras,et al.  Excitation intensity dependence of photoluminescence from monolayers of MoS2 and WS2/MoS2 heterostructures , 2016 .

[26]  Maneesh K. Gupta,et al.  Direct synthesis of ultra-thin large area transition metal dichalcogenides and their heterostructures on stretchable polymer surfaces , 2016 .

[27]  N. Mahmood,et al.  Fabrication of zero to three dimensional nanostructured molybdenum sulfides and their electrochemical and photocatalytic applications. , 2016, Nanoscale.

[28]  E. Pop,et al.  Kinetic Study of Hydrogen Evolution Reaction over Strained MoS2 with Sulfur Vacancies Using Scanning Electrochemical Microscopy. , 2016, Journal of the American Chemical Society.

[29]  A. Tiwari,et al.  Atomically Thin MoS2: A Versatile Nongraphene 2D Material , 2016 .

[30]  M. Terrones,et al.  Defect engineering of two-dimensional transition metal dichalcogenides , 2016 .

[31]  J. Warner,et al.  Detailed Atomic Reconstruction of Extended Line Defects in Monolayer MoS2. , 2016, ACS nano.

[32]  T. Rabczuk,et al.  Mechanical response of all-MoS2 single-layer heterostructures: a ReaxFF investigation. , 2016, Physical chemistry chemical physics : PCCP.

[33]  H. Wakabayashi,et al.  Improving crystalline quality of sputtering-deposited MoS2 thin film by postdeposition sulfurization annealing using (t-C4H9)2S2 , 2016 .

[34]  Priya Vashishta,et al.  Computational Synthesis of MoS2 Layers by Reactive Molecular Dynamics Simulations: Initial Sulfidation of MoO3 Surfaces. , 2017, Nano letters.

[35]  R. Hennig,et al.  Topology-Scaling Identification of Layered Solids and Stable Exfoliated 2D Materials. , 2016, Physical review letters.

[36]  Jun Yuan,et al.  Capture the growth kinetics of CVD growth of two-dimensional MoS2 , 2016, npj 2D Materials and Applications.

[37]  Y. J. Yoon,et al.  Atomic rearrangement of a sputtered MoS2 film from amorphous to a 2D layered structure by electron beam irradiation , 2017, Scientific Reports.

[38]  A. Nakano,et al.  Reactivity of Sulfur Molecules on MoO3 (010) Surface. , 2017, The journal of physical chemistry letters.

[39]  I. Beinik,et al.  Single-layer MoS2 formation by sulfidation of molybdenum oxides in different oxidation states on Au(111). , 2017, Physical chemistry chemical physics : PCCP.

[40]  F. Ding,et al.  Energetics and kinetics of phase transition between a 2H and a 1T MoS2 monolayer-a theoretical study. , 2017, Nanoscale.

[41]  Rajiv K. Kalia,et al.  Chemical Vapor Deposition Synthesis of MoS2 Layers from the Direct Sulfidation of MoO3 Surfaces Using Reactive Molecular Dynamics Simulations , 2018 .

[42]  Zhiliang Zhang,et al.  Grain-Size-Controlled Mechanical Properties of Polycrystalline Monolayer MoS2. , 2018, Nano letters.