Boosting bulk photovoltaic effect in transition metal dichalcogenide by edge semimetal contact

Shuang Qiao; Jihong Liu; Chengdong Yao; Ni Yang; Fangyuan Zheng; Wanqing Meng; Yi Wan; Philip C Y Chow; Dong-Keun Ki; Lijie Zhang; Yumeng Shi; Lain-Jong Li

doi:10.1038/s41377-024-01691-z

Boosting bulk photovoltaic effect in transition metal dichalcogenide by edge semimetal contact

Light Sci Appl. 2025 Jan 2;14(1):22. doi: 10.1038/s41377-024-01691-z.

Authors

Shuang Qiao^#^{1

2}, Jihong Liu^#³, Chengdong Yao⁴, Ni Yang⁴, Fangyuan Zheng⁴, Wanqing Meng⁴, Yi Wan⁴, Philip C Y Chow⁴, Dong-Keun Ki⁵, Lijie Zhang⁶, Yumeng Shi⁷, Lain-Jong Li⁸

Affiliations

¹ Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science and Technology, Hebei University, 071002, Baoding, China. [email protected].
² Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China. [email protected].
³ Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science and Technology, Hebei University, 071002, Baoding, China.
⁴ Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
⁵ Department of Physics and HK Institute of Quantum Science & Technology, The University of Hong Kong, Hong Kong, China.
⁶ Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, China.
⁷ Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Physical Science and Engineering, Beijing Jiaotong University, 100044, Beijing, China.
⁸ Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China. [email protected].

^# Contributed equally.

Abstract

Oxide materials with a non-centrosymmetric structure exhibit bulk photovoltaic effect (BPVE) but with a low cell efficiency. Over the past few years, relatively larger BPVE coefficients have been reported for two-dimensional (2D) layers and stacks with asymmety-induced spontaneous polarization. Here, we report a crucial breakthrough in boosting the BPVE in 3R-MoS₂ by adopting edge contact (EC) geometry using bismuth semimetal electrode. In clear contrast to the typically used top contact (TC) geometry, the EC metal which strongly adheres to the edges and the subtrates can induce a pronounced tensile strain to the 3R-MoS₂, and the lateral contact geometry allows to completely access to in-plane polarization from underneath layers reachable by light, leading to >100 times of BPVE enhancement in photocurrent. We further design a 3R-MoS₂/WSe₂ heterojunction to demonstrate constructive coupling of BPVE with the conventional photovoltaic effect, indicating their potential in photodetectors and photovoltaic devices.