Gate-tunable hot electron extraction in a two-dimensional semiconductor heterojunction

Fuente: arXiv
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Hauptverfasser: Xu, Chenran, Xu, Chen, Zhou, Jichen, Shan, Zhexu, Su, Wenjian, Li, Wenbing, Xu, Xingqi, Watanabe, Kenji, Taniguchi, Takashi, Zhu, Shiyao, Wang, Da-Wei, Tang, Yanhao
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Veröffentlicht: 2025
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author Xu, Chenran
Xu, Chen
Zhou, Jichen
Shan, Zhexu
Su, Wenjian
Li, Wenbing
Xu, Xingqi
Watanabe, Kenji
Taniguchi, Takashi
Zhu, Shiyao
Wang, Da-Wei
Tang, Yanhao
author_facet Xu, Chenran
Xu, Chen
Zhou, Jichen
Shan, Zhexu
Su, Wenjian
Li, Wenbing
Xu, Xingqi
Watanabe, Kenji
Taniguchi, Takashi
Zhu, Shiyao
Wang, Da-Wei
Tang, Yanhao
contents Hot carrier solar cells (HCSCs), harvesting excess energy of the hot carriers generated by above-band-gap photoexcitation, is crucial for pushing the solar cell efficiency beyond the Shockley Queisser limit, which is challenging to realize mainly due to fast hot-carrier cooling. By performing transient reflectance spectroscopy in a MoSe2/hBN/WS2 junction, we demonstrate the gate-tunable harvest of hot electrons from MoSe2 to WS2. By spectrally distinguishing hot-electron extraction from lattice temperature increase, we find that electrostatically doped electrons in MoSe2 can boost hot-electron extraction density (n_ET) by factor up to several tens. Such enhancement arises from interaction between hot excitons and doped electrons, which converts the excess energy of hot excitons to excitations of the Fermi sea and hence generates hot electrons. Moreover, n_ET can be further enhanced by reducing the conduction band offset with external electric field. Our results provide in-depth insights into design of HCSCs with electrostatic strategies.
format Preprint
id arxiv_https___arxiv_org_abs_2504_05859
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Gate-tunable hot electron extraction in a two-dimensional semiconductor heterojunction
Xu, Chenran
Xu, Chen
Zhou, Jichen
Shan, Zhexu
Su, Wenjian
Li, Wenbing
Xu, Xingqi
Watanabe, Kenji
Taniguchi, Takashi
Zhu, Shiyao
Wang, Da-Wei
Tang, Yanhao
Mesoscale and Nanoscale Physics
Materials Science
Hot carrier solar cells (HCSCs), harvesting excess energy of the hot carriers generated by above-band-gap photoexcitation, is crucial for pushing the solar cell efficiency beyond the Shockley Queisser limit, which is challenging to realize mainly due to fast hot-carrier cooling. By performing transient reflectance spectroscopy in a MoSe2/hBN/WS2 junction, we demonstrate the gate-tunable harvest of hot electrons from MoSe2 to WS2. By spectrally distinguishing hot-electron extraction from lattice temperature increase, we find that electrostatically doped electrons in MoSe2 can boost hot-electron extraction density (n_ET) by factor up to several tens. Such enhancement arises from interaction between hot excitons and doped electrons, which converts the excess energy of hot excitons to excitations of the Fermi sea and hence generates hot electrons. Moreover, n_ET can be further enhanced by reducing the conduction band offset with external electric field. Our results provide in-depth insights into design of HCSCs with electrostatic strategies.
title Gate-tunable hot electron extraction in a two-dimensional semiconductor heterojunction
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2504.05859