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Gate-Tunable Hot Electron Extraction in a Two-Dimensional Semiconductor Heterojunction
Chenran Xu1,2, Chen Xu1,2, Jichen Zhou1,2
1School of Physics, Zhejiang University, Hangzhou 310027, China.
Nano Letters
|April 21, 2025
Summary
Hot carrier solar cells can exceed efficiency limits by harvesting hot electrons. Electrostatic doping in MoSe2/hBN/WS2 junctions significantly boosts hot electron extraction, offering new design strategies for advanced solar energy conversion.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Renewable Energy
Background:
- Hot carrier solar cells (HCSCs) aim to surpass the Shockley-Queisser limit by utilizing excess energy from photoexcited carriers.
- Fast hot-carrier cooling is a major obstacle to realizing high-efficiency HCSCs.
Purpose of the Study:
- To demonstrate gate-tunable hot electron harvesting in a MoSe2/hBN/WS2 heterostructure.
- To investigate methods for enhancing hot electron extraction density for improved solar cell performance.
Main Methods:
- Transient reflectance spectroscopy was employed to study carrier dynamics.
- MoSe2/hBN/WS2 junctions were fabricated and characterized.
- External electric fields and electrostatic doping were utilized to tune carrier properties.
Main Results:
- Gate-tunable extraction of hot electrons from MoSe2 to WS2 was successfully demonstrated.
- Electrostatically doped electrons in MoSe2 enhanced hot electron extraction density by up to several tens.
- Reducing the conduction band offset with an external electric field further boosted hot electron extraction.
Conclusions:
- The interaction between hot excitons and doped electrons enhances hot electron generation.
- Electrostatic strategies offer a promising pathway for designing efficient hot carrier solar cells.
- This work provides critical insights for advancing solar energy conversion technologies.
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