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Angstrom-Size Defect Creation and Ionic Transport through Pores in Single-Layer MoS2
Jothi Priyanka Thiruraman, Kazunori Fujisawa, Gopinath Danda
1Laboratoire Interdisciplinaire Carnot de Bourgogne UMR 6303 CNRS-Université de Bourgogne Franche Comté , 9 Avenue Alain Savary , BP 47870, F-21078 Dijon Cedex , France.
Nano Letters
|February 22, 2018
Summary
Researchers engineered sub-nanometer atomic defects in molybdenum disulfide (MoS2) membranes to create nanopores for filtration. Experiments confirmed that only larger pores conduct ions, laying groundwork for angstrom-scale transport studies.
Area of Science:
- Materials Science
- Nanotechnology
- Surface Science
Background:
- Atomic-defect engineering in 2D materials offers potential for advanced filtration and sensing applications.
- Molecular-dynamics (MD) simulations have modeled ionic transport through vacancies, but experimental validation is limited.
Purpose of the Study:
- To experimentally create and characterize sub-nanometer atomic vacancies in molybdenum disulfide (MoS2) membranes.
- To investigate the ionic transport properties through these engineered nanopores.
- To correlate experimental findings with molecular-dynamics simulations.
Main Methods:
- Fabrication of suspended single-layer MoS2 membranes.
- Sub-nanometer vacancy creation using Gallium (Ga+) ion irradiation.
- Characterization via aberration-corrected scanning transmission electron microscopy (AC-STEM).
- Spectroscopic analysis using Raman and photoluminescence.
- Ionic transport measurements (current-voltage characteristics).
- Comparison with molecular-dynamics (MD) simulations.
Main Results:
- Successfully created MoS2 membranes with 300-1200 sub-nanometer pores (average ~0.5 nm, max ~1 nm).
- AC-STEM confirmed vacancies with missing Mo and S atoms.
- Spectroscopy revealed defect-related signals.
- Ionic conductance correlated with ~1 nm pores, indicating negligible transport through smaller (<0.6 nm) pores.
- MD simulations supported experimental findings on pore impermeability.
Conclusions:
- Engineered sub-nanometer atomic defects in MoS2 membranes create functional nanopores for ionic transport studies.
- Pore size distribution and atomic structure critically influence ionic conductance at the sub-nanometer scale.
- This work provides a foundation for experimental investigations of transport phenomena in angstrom-scale pores.
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