NaCl-assisted one-step growth of MoS2–WS2 in-plane heterostructures

Transition metal dichalcogenides (TMDs) have attracted considerable interest for exploration of next-generation electronics and optoelectronics in recent years. Fabrication of in-plane lateral heterostructures between TMDs has opened up excellent opportunities for engineering two-dimensional materials. The creation of high quality heterostructures with a facile method is highly desirable but it still remains challenging. In this work, we demonstrate a one-step growth method for the construction of high-quality MoS2-WS2 in-plane heterostructures. The synthesis was carried out using ambient pressure chemical vapor deposition (APCVD) with the assistance of sodium chloride (NaCl). It was found that the addition of NaCl played a key role in lowering the growth temperatures, in which the Na-containing precursors could be formed and condensed on the substrates to reduce the energy of the reaction. As a result, the growth regimes of MoS2 and WS2 are better matched, leading to the formation of in-plane heterostructures in a single step. The heterostructures were proved to be of high quality with a sharp and clear interface. This newly developed strategy with the assistance of NaCl is promising for synthesizing other TMDs and their heterostructures.

[1]  Lain‐Jong Li,et al.  Band Alignment of 2D Transition Metal Dichalcogenide Heterojunctions , 2017 .

[2]  S. Sanvito,et al.  Possible doping strategies for MoS 2 monolayers: An ab initio study , 2013 .

[3]  Hua Zhang.  Ultrathin Two-Dimensional Nanomaterials. , 2015, ACS nano.

[4]  Jing Kong,et al.  Role of the seeding promoter in MoS2 growth by chemical vapor deposition. , 2014, Nano letters.

[5]  Hongzheng Chen,et al.  Hierarchical architecture of WS2 nanosheets on graphene frameworks with enhanced electrochemical properties for lithium storage and hydrogen evolution , 2015 .

[6]  Moon J. Kim,et al.  MoS2 transistors with 1-nanometer gate lengths , 2016, Science.

[7]  K. Ozoemena,et al.  Symmetric pseudocapacitors based on molybdenum disulfide (MoS2)-modified carbon nanospheres: correlating physicochemistry and synergistic interaction on energy storage , 2016 .

[8]  M. Pimenta,et al.  Comparative study of Raman spectroscopy in graphene and MoS2-type transition metal dichalcogenides. , 2015, Accounts of chemical research.

[9]  J. Warner,et al.  Controlling sulphur precursor addition for large single crystal domains of WS2. , 2014, Nanoscale.

[10]  Wei Chen,et al.  Observation of Strong Interlayer Coupling in MoS2/WS2 Heterostructures , 2016, Advanced materials.

[11]  Timothy C. Berkelbach,et al.  Grains and grain boundaries in highly crystalline monolayer molybdenum disulphide. , 2013, Nature Materials.

[12]  Kuan-Hua Huang,et al.  Synthesis of lateral heterostructures of semiconducting atomic layers. , 2015, Nano letters.

[13]  Jun Lou,et al.  Vertical and in-plane heterostructures from WS2/MoS2 monolayers. , 2014, Nature materials.

[14]  P. Ajayan,et al.  Two-Step Growth of Two-Dimensional WSe2/MoSe2 Heterostructures. , 2015, Nano letters.

[15]  Andrew M Rappe,et al.  Monolayer Single-Crystal 1T'-MoTe2 Grown by Chemical Vapor Deposition Exhibits Weak Antilocalization Effect. , 2016, Nano letters.

[16]  Bingbing Tian,et al.  Lateral Epitaxy of Atomically Sharp WSe2/WS2 Heterojunctions on Silicon Dioxide Substrates , 2016 .

[17]  Zhiyuan Zeng,et al.  An effective method for the fabrication of few-layer-thick inorganic nanosheets. , 2012, Angewandte Chemie.

[18]  P. Ajayan,et al.  Solid-Vapor Reaction Growth of Transition-Metal Dichalcogenide Monolayers. , 2016, Angewandte Chemie.

[19]  Myoung-Jae Lee,et al.  Rotation‐Misfit‐Free Heteroepitaxial Stacking and Stitching Growth of Hexagonal Transition‐Metal Dichalcogenide Monolayers by Nucleation Kinetics Controls , 2015, Advanced materials.

[20]  Nikhil V. Medhekar,et al.  Ab initio characterization of layered MoS2 as anode for sodium-ion batteries , 2014 .

[21]  P. Ajayan,et al.  Band engineering for novel two-dimensional atomic layers. , 2015, Small.

[22]  B. Jonker,et al.  Synthesis of Large-Area WS2 monolayers with Exceptional Photoluminescence , 2015, Scientific Reports.

[23]  X. Tao,et al.  Salt-assisted direct exfoliation of graphite into high-quality, large-size, few-layer graphene sheets. , 2013, Nanoscale.

[24]  David B. Geohegan,et al.  Equally E ffi cient Interlayer Exciton Relaxation and Improved Absorption in Epitaxial and Nonepitaxial MoS 2 / WS 2 Heterostructures , 2015 .

[25]  Robert Vajtai,et al.  Tellurium-Assisted Low-Temperature Synthesis of MoS2 and WS2 Monolayers. , 2015, ACS nano.

[26]  Jing Kong,et al.  Parallel Stitching of 2D Materials. , 2016, Advanced materials.

[27]  V. Dravid,et al.  Growth Mechanism of Transition Metal Dichalcogenide Monolayers: The Role of Self-Seeding Fullerene Nuclei. , 2016, ACS nano.

[28]  Jean-Christophe Charlier,et al.  Identification of individual and few layers of WS2 using Raman Spectroscopy , 2013, Scientific Reports.

[29]  Yiwei Zhao,et al.  Performance Upper Limit of sub‐10 nm Monolayer MoS2 Transistors , 2016, The Journal of Physical Chemistry C.

[30]  Y. Chui,et al.  Salt-assisted high-throughput synthesis of single- and few-layer transition metal dichalcogenides and their application in organic solar cells. , 2014, Small.

[31]  Bo Liu,et al.  High yield exfoliation of two-dimensional chalcogenides using sodium naphthalenide , 2014, Nature Communications.

[32]  G. Eda,et al.  Evidence for Fast Interlayer Energy Transfer in MoSe2/WS2 Heterostructures. , 2015, Nano letters.

[33]  J. Johns,et al.  Seed Crystal Homogeneity Controls Lateral and Vertical Heteroepitaxy of Monolayer MoS2 and WS2. , 2015, Journal of the American Chemical Society.

[34]  Dmitri Golberg,et al.  Halide-Assisted Atmospheric Pressure Growth of Large WSe2 and WS2 Monolayer Crystals , 2015 .

[35]  H. Tan,et al.  Fluorescence Concentric Triangles: A Case of Chemical Heterogeneity in WS2 Atomic Monolayer. , 2016, Nano letters.

[36]  Liquan Chen,et al.  Atomic-scale clarification of structural transition of MoS₂ upon sodium intercalation. , 2014, ACS nano.

[37]  S. Jadkar,et al.  Large area chemical vapor deposition of monolayer transition metal dichalcogenides and their temperature dependent Raman spectroscopy studies. , 2016, Nanoscale.

[38]  C. Shi,et al.  Scalable synthesis of high-quality transition metal dichalcogenide nanosheets and their application as sodium-ion battery anodes , 2016 .

[39]  J. Zabinski,et al.  Disorder-Induced Low-Frequency Raman Band Observed in Deposited MoS2 Films , 1994 .

[40]  David O. Scanlon,et al.  Theoretical and Experimental Study of the Electronic Structures of MoO3 and MoO2 , 2010 .

[41]  Xi Wan,et al.  Electronic Properties of MoS2-WS2 Heterostructures Synthesized with Two-Step Lateral Epitaxial Strategy. , 2015, ACS nano.

[42]  I. Ivanov,et al.  Patterned arrays of lateral heterojunctions within monolayer two-dimensional semiconductors , 2015, Nature Communications.

[43]  R. Frindt,et al.  Li-intercalation and exfoliation of WS2 , 1996 .

[44]  Wang Yao,et al.  Lateral heterojunctions within monolayer MoSe2-WSe2 semiconductors. , 2014, Nature materials.

[45]  Ying Chen,et al.  Achieving Uniform Monolayer Transition Metal Dichalcogenides Film on Silicon Wafer via Silanization Treatment: A Typical Study on WS2 , 2017, Advanced materials.

[46]  J. Warner,et al.  Substrate control for large area continuous films of monolayer MoS2 by atmospheric pressure chemical vapor deposition , 2016, Nanotechnology.

[47]  K. Loh,et al.  Phase-engineered transition-metal dichalcogenides for energy and electronics , 2015 .

[48]  G. Duscher,et al.  Interlayer Coupling in Twisted WSe2/WS2 Bilayer Heterostructures Revealed by Optical Spectroscopy. , 2016, ACS nano.

[49]  M. Terrones,et al.  Intervalley scattering by acoustic phonons in two-dimensional MoS2 revealed by double-resonance Raman spectroscopy , 2017, Nature Communications.

[50]  Gautam Gupta,et al.  Chemical Vapor Deposition Synthesized Atomically Thin Molybdenum Disulfide with Optoelectronic-Grade Crystalline Quality. , 2015, ACS nano.

[51]  Jianbin Xu,et al.  Epitaxial Stitching and Stacking Growth of Atomically Thin Transition‐Metal Dichalcogenides (TMDCs) Heterojunctions , 2017 .

[52]  Song Liu,et al.  Diffusion-Mediated Synthesis of MoS2/WS2 Lateral Heterostructures. , 2016, Nano letters.

[53]  Lianmao Peng,et al.  Large-area synthesis of high-quality and uniform monolayer WS2 on reusable Au foils , 2015, Nature Communications.

[54]  Jianbin Xu,et al.  Lateral Built‐In Potential of Monolayer MoS2–WS2 In‐Plane Heterostructures by a Shortcut Growth Strategy , 2015, Advanced materials.

[55]  Sidney R. Cohen,et al.  Intercalation of Inorganic Fullerene-like Structures Yields Photosensitive Films and New Tips for Scanning Probe Microscopy , 1997 .

[56]  Gang Hee Han,et al.  Seeded growth of highly crystalline molybdenum disulphide monolayers at controlled locations , 2015, Nature Communications.

[57]  Gyeong Sook Bang,et al.  Effective liquid-phase exfoliation and sodium ion battery application of MoS2 nanosheets. , 2014, ACS applied materials & interfaces.

[58]  Harish Bhaskaran,et al.  Shape Evolution of Monolayer MoS2 Crystals Grown by Chemical Vapor Deposition , 2014 .

[59]  Xiaohua Ma,et al.  Controllable growth of monolayer MoS2 by chemical vapor deposition via close MoO2 precursor for electrical and optical applications , 2017, Nanotechnology.

[60]  Xiaodong Xu,et al.  Vapor-solid growth of high optical quality MoS₂ monolayers with near-unity valley polarization. , 2013, ACS nano.

[61]  Yi Liu,et al.  Equally efficient interlayer exciton relaxation and improved absorption in epitaxial and nonepitaxial MoS2/WS2 heterostructures. , 2014, Nano letters.

[62]  Sung‐Yool Choi,et al.  Effective shape-controlled growth of monolayer MoS2 flakes by powder-based chemical vapor deposition , 2016, Nano Research.

[63]  J. M. Kikkawa,et al.  Monolayer Single-Crystal 1 T ′-MoTe 2 Grown by Chemical Vapor Deposition Exhibits Weak Antilocalization , 2016 .

[64]  Jr-hau He,et al.  Epitaxial growth of a monolayer WSe2-MoS2 lateral p-n junction with an atomically sharp interface , 2015, Science.

[65]  Influence of Stoichiometry on the Optical and Electrical Properties of Chemical Vapor Deposition Derived MoS2 , 2014, ACS nano.

[66]  Litao Sun,et al.  Synthesis and Optical Properties of Large‐Area Single‐Crystalline 2D Semiconductor WS2 Monolayer from Chemical Vapor Deposition , 2014 .

[67]  Bingbing Tian,et al.  Chemical Vapor Deposition of High‐Quality Large‐Sized MoS2 Crystals on Silicon Dioxide Substrates , 2016, Advanced science.

[68]  Yu Kobayashi,et al.  Bandgap-tunable lateral and vertical heterostructures based on monolayer Mo1-xWxS2 alloys , 2015, Nano Research.

[69]  Wang Yao,et al.  Lateral heterojunctions within monolayer semiconductors , 2014 .

[70]  Hongzheng Chen,et al.  Elucidation of Zero‐Dimensional to Two‐Dimensional Growth Transition in MoS2 Chemical Vapor Deposition Synthesis , 2017 .

[71]  C. Jin,et al.  Two-Dimensional Layered Heterostructures Synthesized from Core-Shell Nanowires. , 2015, Angewandte Chemie.

[72]  Xiaodong Xu,et al.  Valleytronics in 2D materials , 2016 .