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Reidy K, Mortelmans W, Jo SS, Penn AN, Foucher AC, Liu Z, Cai T, Wang B, Ross FM, Jaramillo R. Atomic-Scale Mechanisms of MoS 2 Oxidation for Kinetic Control of MoS 2/MoO 3 Interfaces. NANO LETTERS 2023. [PMID: 37368991 DOI: 10.1021/acs.nanolett.3c00303] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Oxidation of transition metal dichalcogenides (TMDs) occurs readily under a variety of conditions. Therefore, understanding the oxidation processes is necessary for successful TMD handling and device fabrication. Here, we investigate atomic-scale oxidation mechanisms of the most widely studied TMD, MoS2. We find that thermal oxidation results in α-phase crystalline MoO3 with sharp interfaces, voids, and crystallographic alignment with the underlying MoS2. Experiments with remote substrates prove that thermal oxidation proceeds via vapor-phase mass transport and redeposition, a challenge to forming thin, conformal films. Oxygen plasma accelerates the kinetics of oxidation relative to the kinetics of mass transport, forming smooth and conformal oxides. The resulting amorphous MoO3 can be grown with subnanometer to several-nanometer thickness, and we calibrate the oxidation rate for different instruments and process parameters. Our results provide quantitative guidance for managing both the atomic scale structure and thin-film morphology of oxides in the design and processing of TMD devices.
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Affiliation(s)
- Kate Reidy
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Wouter Mortelmans
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Seong Soon Jo
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Aubrey N Penn
- MIT.nano, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alexandre C Foucher
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Zhenjing Liu
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Kowloon 999077, Hong Kong, China
| | - Tao Cai
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Baoming Wang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Frances M Ross
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - R Jaramillo
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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Activating MoS2 via electronic structure modulation and phase engineering for hydrogen evolution reaction. CATAL COMMUN 2022. [DOI: 10.1016/j.catcom.2022.106427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Yoon A, Kim JH, Lee Z. Elucidation of Novel Potassium-Mediated Oxidation and Etching of Two-Dimensional Transition Metal Dichalcogenides. ACS APPLIED MATERIALS & INTERFACES 2021; 13:49163-49171. [PMID: 34632769 DOI: 10.1021/acsami.1c13607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Preparation of edge-rich two-dimensional (2D) transition metal dichalocogenides (TMDs) has been actively investigated with the aim to improve their electrical and catalytic properties. Here, we elucidate the role of potassium ions in oxidation of TMDs and suggest a consequent novel anisotropic etching mechanism driven by self-running oxide droplets. We discover that potassium-mediated oxidation of MoS2 leads to the formation of K-intercalated hexagonal-phase molybdenum oxides (h-KxMoO3), whereas orthorhombic-phase oxides are formed in the absence of potassium ions. Metastable h-KxMoO3 appears to have decomposed into oxide droplets at higher temperature. Self-running of the oxide droplets leads to layer-by-layer anisotropic etching of MoS2 along the armchair direction. The motion of the droplets appears to be triggered by the surface energy instability between the oxide droplets and the underlying MoS2 layer. This study opens new possibilities to design and manufacture novel edge-rich 2D TMDs that do not follow the equilibrium Wulff shape by modulating their oxidation with the assistance of alkali metals and also offers fundamental insights into the interactions between nanodroplets and 2D materials toward edge engineering.
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Affiliation(s)
- Aram Yoon
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jung Hwa Kim
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Zonghoon Lee
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
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Park S, Garcia‐Esparza AT, Abroshan H, Abraham B, Vinson J, Gallo A, Nordlund D, Park J, Kim TR, Vallez L, Alonso‐Mori R, Sokaras D, Zheng X. Operando Study of Thermal Oxidation of Monolayer MoS 2. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002768. [PMID: 33977043 PMCID: PMC8097340 DOI: 10.1002/advs.202002768] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 01/12/2021] [Indexed: 06/12/2023]
Abstract
Monolayer MoS2 is a promising semiconductor to overcome the physical dimension limits of microelectronic devices. Understanding the thermochemical stability of MoS2 is essential since these devices generate heat and are susceptible to oxidative environments. Herein, the promoting effect of molybdenum oxides (MoO x ) particles on the thermal oxidation of MoS2 monolayers is shown by employing operando X-ray absorption spectroscopy, ex situ scanning electron microscopy and X-ray photoelectron spectroscopy. The study demonstrates that chemical vapor deposition-grown MoS2 monolayers contain intrinsic MoO x and are quickly oxidized at 100 °C (3 vol% O2/He), in contrast to previously reported oxidation thresholds (e.g., 250 °C, t ≤ 1 h in the air). Otherwise, removing MoO x increases the thermal oxidation onset temperature of monolayer MoS2 to 300 °C. These results indicate that MoO x promote oxidation. An oxide-free lattice is critical to the long-term stability of monolayer MoS2 in state-of-the-art 2D electronic, optical, and catalytic applications.
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Affiliation(s)
- Sangwook Park
- Department of Mechanical EngineeringStanford UniversityStanfordCA94305USA
- Department of Mechanical EngineeringSeoul National UniversitySeoul08826South Korea
| | - Angel T. Garcia‐Esparza
- Department of Mechanical EngineeringStanford UniversityStanfordCA94305USA
- Stanford Synchrotron Radiation LightsourceSLAC National Accelerator Laboratory2575 Sand Hill RoadMenlo ParkCA94025USA
| | - Hadi Abroshan
- SUNCAT Center for Interface Science and CatalysisSLAC National Accelerator Laboratory2575 Sand Hill RoadMenlo ParkCA94025USA
- School of Chemistry and BiochemistryGeorgia Institute of TechnologyAtlantaGA30332USA
| | - Baxter Abraham
- Stanford Synchrotron Radiation LightsourceSLAC National Accelerator Laboratory2575 Sand Hill RoadMenlo ParkCA94025USA
- Linac Coherent Light SourceSLAC National Accelerator Laboratory2575 Sand Hill RoadMenlo ParkCA94025USA
| | - John Vinson
- National Institute of Standards and Technology100 Bureau DriveGaithersburgMD20899USA
| | - Alessandro Gallo
- SUNCAT Center for Interface Science and CatalysisSLAC National Accelerator Laboratory2575 Sand Hill RoadMenlo ParkCA94025USA
| | - Dennis Nordlund
- Stanford Synchrotron Radiation LightsourceSLAC National Accelerator Laboratory2575 Sand Hill RoadMenlo ParkCA94025USA
| | - Joonsuk Park
- Materials Science and EngineeringStanford UniversityStanfordCA94305USA
| | - Taeho Roy Kim
- Stanford Nano Shared FacilitiesStanford UniversityStanfordCA94305USA
| | - Lauren Vallez
- Department of Mechanical EngineeringStanford UniversityStanfordCA94305USA
| | - Roberto Alonso‐Mori
- Linac Coherent Light SourceSLAC National Accelerator Laboratory2575 Sand Hill RoadMenlo ParkCA94025USA
| | - Dimosthenis Sokaras
- Stanford Synchrotron Radiation LightsourceSLAC National Accelerator Laboratory2575 Sand Hill RoadMenlo ParkCA94025USA
| | - Xiaolin Zheng
- Department of Mechanical EngineeringStanford UniversityStanfordCA94305USA
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