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Published on: September 23, 2018
Graphene-Mediated Contact Engineering for a High Thermoelectric Performance in 2D PdSe2
Lingling Xu1, Zehao Yu1, Meilin Li1
1Phonon Engineering Research Center of Jiangsu Province, Ministry of Education Key Laboratory of Numerical Simulation of Large-Scale Complex System, Center for Quantum Transport and Thermal Energy Science, Institute of Physics Frontiers and Interdisciplinary Sciences, School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China.
This study introduces a new design for two-dimensional (2D) thermoelectric materials, significantly reducing contact resistance. This breakthrough enhances electrical performance and achieves record power factors in 2D palladium diselenide (PdSe2) systems.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Theoretical predictions suggest two-dimensional (2D) thermoelectric (TE) materials offer superior performance over bulk counterparts.
- Experimental validation is hindered by high contact resistance in 2D materials due to their large surface-to-volume ratio.
- Accurate evaluation of intrinsic TE properties requires mitigation of contact-related issues.
Purpose of the Study:
- To develop a contact engineering strategy to overcome limitations in measuring 2D TE material properties.
- To enhance the electrical performance and thermoelectric figure of merit (PF) in few-layer palladium diselenide (PdSe2).
- To establish a reliable method for probing intrinsic TE properties of 2D materials.
Main Methods:
- Fabrication of a field-effect transistor architecture using few-layer graphene electrodes.
- Integration of a few-layer palladium diselenide (PdSe2) channel.
- Full encapsulation of the device using hexagonal boron nitride (h-BN).
- Characterization of contact resistance and thermoelectric performance.
Main Results:
- Achieved significantly reduced contact resistance through engineered interfaces.
- Demonstrated enhanced electrical performance and overcame the conductivity-Seebeck coefficient trade-off in few-layer PdSe2.
- Attained a power factor (PF) of approximately 1.55 mW m⁻² K⁻² at room temperature, a record for 2D PdSe2 systems.
Conclusions:
- The proposed contact engineering approach enables accurate probing of intrinsic TE properties in 2D materials.
- The developed architecture significantly boosts the thermoelectric performance of 2D materials.
- This work highlights the critical role of contact engineering for realizing high-efficiency 2D thermoelectric devices.
