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High Pressure Vibrational Properties of WS2 Nanotubes
K R O'Neal1, J G Cherian1, A Zak2
1Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.
Nano Letters
|December 18, 2015
Summary
We studied tungsten disulfide (WS2) nanotubes under pressure using spectroscopy. The A1g mode showed high sensitivity to strain, indicating a breakdown pathway, while infrared response revealed modest conductivity due to tube-to-tube hopping.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Tungsten disulfide (WS2) nanotubes are promising nanomaterials with unique electronic and vibrational properties.
- Understanding their behavior under external stimuli like pressure is crucial for device applications.
Purpose of the Study:
- To investigate the vibrational and electronic properties of multiwall WS2 nanotubes under high pressure.
- To identify the strain-dependent behavior and potential breakdown mechanisms of WS2 nanotubes.
Main Methods:
- Synchrotron-based infrared and Raman spectroscopies were employed.
- Diamond anvil cell techniques were used to apply hydrostatic pressure.
- Analysis of frequency shifts and lattice dynamics provided insights.
Main Results:
- Most vibrational modes hardened under pressure, but the Raman-active A1g breathing mode showed a significantly higher response.
- This enhanced sensitivity of the A1g mode suggests it dictates the nanotube's strain-induced breakdown pathway.
- High-pressure infrared spectroscopy revealed localized absorption, fitting a percolation model.
- This indicates a modest macroscopic conductivity in WS2 nanotubes attributed to inter-tube hopping.
Conclusions:
- The A1g breathing mode is a critical indicator of strain-induced failure in WS2 nanotubes.
- WS2 nanotubes exhibit measurable conductivity through tube-to-tube hopping.
- The study provides novel insights into the interplay between vibrational and electronic properties of WS2 nanotubes under pressure.
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