Strain-Modulated Photoelectric Responses from a Flexible α-In2Se3/3R MoS2 Heterojunction

Weifan Cai; Jingyuan Wang; Yongmin He; Sheng Liu; Qihua Xiong; Zheng Liu; Qing Zhang

doi:10.1007/s40820-020-00584-1

Strain-Modulated Photoelectric Responses from a Flexible α-In₂Se₃/3R MoS₂ Heterojunction

Nanomicro Lett. 2021 Feb 15;13(1):74. doi: 10.1007/s40820-020-00584-1.

Authors

Weifan Cai¹, Jingyuan Wang¹, Yongmin He², Sheng Liu³, Qihua Xiong³, Zheng Liu², Qing Zhang⁴

Affiliations

¹ Center for Micro- and Nano-Electronics, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
² School of Materials Science and Engineering, Nanyang Technological University, Singapore, 639798, Singapore.
³ Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798, Singapore.
⁴ Center for Micro- and Nano-Electronics, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, 639798, Singapore. eqzhang@ntu.edu.sg.

Abstract

Semiconducting piezoelectric α-In₂Se₃ and 3R MoS₂ have attracted tremendous attention due to their unique electronic properties. Artificial van der Waals (vdWs) heterostructures constructed with α-In₂Se₃ and 3R MoS₂ flakes have shown promising applications in optoelectronics and photocatalysis. Here, we present the first flexible α-In₂Se₃/3R MoS₂ vdWs p-n heterojunction devices for photodetection from the visible to near infrared region. These heterojunction devices exhibit an ultrahigh photoresponsivity of 2.9 × 10³ A W^-1 and a substantial specific detectivity of 6.2 × 10¹⁰ Jones under a compressive strain of - 0.26%. The photocurrent can be increased by 64% under a tensile strain of + 0.35%, due to the heterojunction energy band modulation by piezoelectric polarization charges at the heterojunction interface. This work demonstrates a feasible approach to enhancement of α-In₂Se₃/3R MoS₂ photoelectric response through an appropriate mechanical stimulus.

Keywords: Flexible; Piezoelectric charge; Self-powered photodetector; Strain modulation; α-In2Se3/3R MoS2 heterojunction.