8 results on '"2h-tas2"'
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2. Regulating the Electrical and Mechanical Properties of TaS2 Films via van der Waals and Electrostatic Interaction for High Performance Electromagnetic Interference Shielding.
- Author
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Deng, Fukang, Wei, Jianhong, Xu, Yadong, Lin, Zhiqiang, Lu, Xi, Wan, Yan-Jun, Sun, Rong, Wong, Ching-Ping, and Hu, Yougen
- Subjects
- *
ELECTROMAGNETIC shielding , *ELECTROMAGNETIC interference , *ELECTROSTATIC interaction , *ELECTRIC conductivity , *TRANSITION metals , *CELLULOSE fibers , *ARAMID fibers - Abstract
Highlights: A flexible freestanding TaS2 film (thickness = 3.1 μm) exhibits an ultralow void ratio of 6.01%, an ultra-high electrical conductivity of 2,666 S cm−1, an electromagnetic interference shielding effectiveness (EMI SE) of 41.8 dB, an absolute EMI SE (SSE/t) of 27,859 dB cm2 g−1, and excellent flexibility withstand 1,000 bends without rupture. The TaS2 composite films exhibit excellent EMI shielding properties and higher tensile strength with better mechanical flexibility, making them suitable for EMI shielding practical applications. Low-dimensional transition metal dichalcogenides (TMDs) have unique electronic structure, vibration modes, and physicochemical properties, making them suitable for fundamental studies and cutting-edge applications such as silicon electronics, optoelectronics, and bioelectronics. However, the brittleness, low toughness, and poor mechanical and electrical stabilities of TMD-based films limit their application. Herein, a TaS2 freestanding film with ultralow void ratio of 6.01% is restacked under the effect of bond-free van der Waals (vdW) interactions within the staggered 2H-TaS2 nanosheets. The restacked films demonstrated an exceptionally high electrical conductivity of 2,666 S cm−1, electromagnetic interference shielding effectiveness (EMI SE) of 41.8 dB, and absolute EMI SE (SSE/t) of 27,859 dB cm2 g−1, which is the highest value reported for TMD-based materials. The bond-free vdW interactions between the adjacent 2H-TaS2 nanosheets provide a natural interfacial strain relaxation, achieving excellent flexibility without rupture after 1,000 bends. In addition, the TaS2 nanosheets are further combined with the polymer fibers of bacterial cellulose and aramid nanofibers via electrostatic interactions to significantly enhance the tensile strength and flexibility of the films while maintaining their high electrical conductivity and EMI SE.This work provides promising alternatives for conventional materials used in EMI shielding and nanodevices. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. Regulating the Electrical and Mechanical Properties of TaS2 Films via van der Waals and Electrostatic Interaction for High Performance Electromagnetic Interference Shielding
- Author
-
Deng, Fukang, Wei, Jianhong, Xu, Yadong, Lin, Zhiqiang, Lu, Xi, Wan, Yan-Jun, Sun, Rong, Wong, Ching-Ping, and Hu, Yougen
- Published
- 2023
- Full Text
- View/download PDF
4. Charge density waves and degenerate modes in exfoliated monolayer 2H-TaS2
- Author
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Duan Zhang, Yecun Wu, Yu-Hsin Su, Ming-Chien Hsu, Cormac Ó Coileáin, Jiung Cho, Miri Choi, Byong Sun Chun, Yao Guo, Ching-Ray Chang, and Han-Chun Wu
- Subjects
2h-tas2 ,charge density waves ,transition metal dichalcogenides ,periodic lattice distortion ,degenerate modes ,Crystallography ,QD901-999 - Abstract
Charge density waves spontaneously breaking lattice symmetry through periodic lattice distortion, and electron–electron and electron–phonon interactions, can lead to a new type of electronic band structure. Bulk 2H-TaS2 is an archetypal transition metal dichalcogenide supporting charge density waves with a phase transition at 75 K. Here, it is shown that charge density waves can exist in exfoliated monolayer 2H-TaS2 and the transition temperature can reach 140 K, which is much higher than that in the bulk. The degenerate breathing and wiggle modes of 2H-TaS2 originating from the periodic lattice distortion are probed by optical methods. The results open an avenue to investigating charge density wave phases in two-dimensional transition metal dichalcogenides and will be helpful for understanding and designing devices based on charge density waves.
- Published
- 2020
- Full Text
- View/download PDF
5. Charge density waves and degenerate modes in exfoliated monolayer 2H-TaS2
- Author
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Byong Sun Chun, Yecun Wu, Jiung Cho, Yu-Hsin Su, Han-Chun Wu, Cormac Ó Coileáin, Ching-Ray Chang, Duan Zhang, Ming-Chien Hsu, Yao Guo, and Miri Choi
- Subjects
Phase transition ,Materials science ,02 engineering and technology ,Biochemistry ,03 medical and health sciences ,Distortion ,Monolayer ,General Materials Science ,Electronic band structure ,030304 developmental biology ,0303 health sciences ,degenerate modes ,Crystallography ,Condensed matter physics ,Transition temperature ,Degenerate energy levels ,transition metal dichalcogenides ,charge density waves ,Charge density ,2h-tas2 ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Research Papers ,QD901-999 ,periodic lattice distortion ,0210 nano-technology ,Charge density wave - Abstract
Using temperature-dependent Raman scattering, it is demonstrated for the first time that charge density waves can exist in exfoliated monolayer 2H-TaS2 with a phase transition temperature much higher than that in the bulk., Charge density waves spontaneously breaking lattice symmetry through periodic lattice distortion, and electron–electron and electron–phonon interactions, can lead to a new type of electronic band structure. Bulk 2H-TaS2 is an archetypal transition metal dichalcogenide supporting charge density waves with a phase transition at 75 K. Here, it is shown that charge density waves can exist in exfoliated monolayer 2H-TaS2 and the transition temperature can reach 140 K, which is much higher than that in the bulk. The degenerate breathing and wiggle modes of 2H-TaS2 originating from the periodic lattice distortion are probed by optical methods. The results open an avenue to investigating charge density wave phases in two-dimensional transition metal dichalcogenides and will be helpful for understanding and designing devices based on charge density waves.
- Published
- 2020
6. Possible charge-density-wave signatures in the anomalous resistivity of Li-intercalated multilayer MoS2
- Author
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Qihong Chen, Erik Piatti, Renato Gonnelli, Mauro Tortello, Jianting Ye, and Device Physics of Complex Materials
- Subjects
Phase transition ,TRANSITION-METAL DICHALCOGENIDES ,Materials science ,Charge density waves ,Intercalation (chemistry) ,General Physics and Astronomy ,FOS: Physical sciences ,02 engineering and technology ,Electrolyte ,01 natural sciences ,MoS2 ,Ionic gating ,Intercalation ,Anomalous resistance ,Phase transitions ,STRUCTURAL PHASE-TRANSITION ,MOLYBDENUM-DISULFIDE ,Electrical resistivity and conductivity ,0103 physical sciences ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,1T-TAS2 ,010306 general physics ,2H-TAS2 ,Sheet resistance ,DOME ,Superconductivity ,Condensed Matter - Materials Science ,Condensed matter physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,SUPERCONDUCTIVITY ,Doping ,Materials Science (cond-mat.mtrl-sci) ,Surfaces and Interfaces ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Surfaces, Coatings and Films ,CRYSTALS ,MOBILITY ,0210 nano-technology ,Charge density wave - Abstract
We fabricate ion-gated field-effect transistors (iFET) on mechanically exfoliated multilayer MoS$_2$. We encapsulate the flake by Al$_2$O$_3$, leaving the device channel exposed at the edges only. A stable Li$^+$ intercalation in the MoS$_2$ lattice is induced by gating the samples with a Li-based polymeric electrolyte above $\sim$ 330 K and the doping state is fixed by quenching the device to $\sim$ 300 K. This intercalation process induces the emergence of anomalies in the temperature dependence of the sheet resistance and its first derivative, which are typically associated with structural/electronic/magnetic phase transitions. We suggest that these anomalies in the resistivity of MoS$_2$ can be naturally interpreted as the signature of a transition to a charge-density-wave phase induced by lithiation, in accordance with recent theoretical calculations., Comment: 8 pages, 4 figures
- Published
- 2018
7. Study of charge density waves in suspended 2H-TaS 2 and 2H-TaSe 2 by nanomechanical resonance
- Author
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Makars Šiškins, Samuel Mañas-Valero, Martin Lee, Herre S. J. van der Zant, Eugenio Coronado, and Peter G. Steeneken
- Subjects
Phase transition ,Materials science ,Physics and Astronomy (miscellaneous) ,UNESCO::QUÍMICA ,FOS: Physical sciences ,02 engineering and technology ,01 natural sciences ,QUÍMICA [UNESCO] ,Superconductivity (cond-mat.supr-con) ,Condensed Matter - Strongly Correlated Electrons ,symbols.namesake ,0103 physical sciences ,010302 applied physics ,Superconductivity ,Condensed Matter - Materials Science ,Strongly Correlated Electrons (cond-mat.str-el) ,Condensed matter physics ,Condensed Matter - Superconductivity ,Transition temperature ,2H-TaSe2 ,Materials Science (cond-mat.mtrl-sci) ,Resonance ,Charge density ,021001 nanoscience & nanotechnology ,Hysteresis ,2H-TaS2 ,symbols ,van der Waals force ,0210 nano-technology ,Charge density wave - Abstract
The charge density wave (CDW) state in van der Waals systems shows interesting scaling phenomena as the number of layers can significantly affect the CDW transition temperature, $T_{CDW}$. However, it is often difficult to use conventional methods to study the phase transition in these systems due to their small size and sensitivity to degradation. Degradation is an important parameter which has been shown to greatly influence the superconductivity in layered systems. Since the CDW state competes with the onset of superconductivity, it is expected that $T_{CDW}$ will also be affected by the degradation. Here, we probe the CDW phase transition by the mechanical resonances of suspended 2H-TaS2 and 2H-TaSe2 membranes and study the effect of disorder on the CDW state. Pristine flakes show the transition near the reported values of 75 K and 122 K respectively. We then study the effect of degradation on 2H-TaS2 which displays an enhancement of $T_{CDW}$ up to 129 K after degradation in ambient air. Finally, we study a sample with local degradation and observe that multiple phase transitions occur at 87 K, 103 K and 118 K with a hysteresis in temperature in the same membrane. The observed spatial variations in the Raman spectra suggest that variations in crystal structure cause domains with different transition temperatures which could result in the hysteresis. This work shows the potential of using nanomechanical resonance to characterize the CDW in suspended 2D materials and demonstrate that degradation can have a large effect on transition temperatures., The following article has been accepted by Applied Physics Letters. After it is published, it will be found at [https://doi.org/10.1063/5.0051112]
- Published
- 2021
- Full Text
- View/download PDF
8. Charge density waves and degenerate modes in exfoliated monolayer 2H-TaS 2 .
- Author
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Zhang D, Wu Y, Su YH, Hsu MC, Ó Coileáin C, Cho J, Choi M, Chun BS, Guo Y, Chang CR, and Wu HC
- Abstract
Charge density waves spontaneously breaking lattice symmetry through periodic lattice distortion, and electron-electron and electron-phonon inter-actions, can lead to a new type of electronic band structure. Bulk 2H-TaS
2 is an archetypal transition metal dichalcogenide supporting charge density waves with a phase transition at 75 K. Here, it is shown that charge density waves can exist in exfoliated monolayer 2H-TaS2 and the transition temperature can reach 140 K, which is much higher than that in the bulk. The degenerate breathing and wiggle modes of 2H-TaS2 originating from the periodic lattice distortion are probed by optical methods. The results open an avenue to investigating charge density wave phases in two-dimensional transition metal dichalcogenides and will be helpful for understanding and designing devices based on charge density waves., (© Duan Zhang et al. 2020.)- Published
- 2020
- Full Text
- View/download PDF
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