Issue 30, 2018

Tunable WSe2–CdS mixed-dimensional van der Waals heterojunction with a piezo-phototronic effect for an enhanced flexible photodetector

Abstract

Due to the absence of bond fracture and atomic reconstruction under strain, vdWs structures hold great promise in flexible electronic/optoelectronic applications. Besides all-2D heterojunctions, the dangling-bond-free surfaces of 2D materials also enable vdWs interaction with other materials of different dimensionalities, forming mixed-dimensional vdWs heterostructures. Such structures allow a much broader selection of materials and may provide a promising approach to compensate for the intrinsic weakness of 2D crystals before realizing their full potential. In this study, we present the fabrication of a WSe2–CdS mixed-dimensional vdWs p–n heterojunction for flexible photodetection. A strain-tunable vdWs interface was demonstrated and the photoresponse was dramatically enhanced with the piezo-phototronic effect. The photocurrent can be increased by ∼110% under a compressive strain of −0.73% and the corresponding photoresponsivity reaches up to 33.4 A W−1. The enhancement originates from realigned local energy-band tilting at the WSe2–CdS interface by strain-induced piezopolarization, which promotes the transport process of photoexcited carriers. Our work provides a new route to a tunable vdWs interface other than with electrostatic gating, which may inspire the development of novel flexible vdWs optoelectronics.

Graphical abstract: Tunable WSe2–CdS mixed-dimensional van der Waals heterojunction with a piezo-phototronic effect for an enhanced flexible photodetector

Supplementary files

Article information

Article type
Paper
Submitted
30 Mot 2018
Accepted
11 Upu 2018
First published
12 Upu 2018

Nanoscale, 2018,10, 14472-14479

Tunable WSe2–CdS mixed-dimensional van der Waals heterojunction with a piezo-phototronic effect for an enhanced flexible photodetector

P. Lin, L. Zhu, D. Li, L. Xu and Z. L. Wang, Nanoscale, 2018, 10, 14472 DOI: 10.1039/C8NR04376K

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