High‐Sensitivity Infrared Photoelectric Detection Based on WS2/Si Structure Tuned by Ferroelectrics

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 18; no. 7; pp. e2105188 - n/a
• Main Authors: Zheng, Diyuan, Dong, Xinyuan, Lu, Jing, Niu, Yiru, Wang, Hui
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-02-2022
• Subjects: 2D materials; Electric fields; Electrical junctions; Electrical properties; Energy gap; Ferroelectric materials; Ferroelectricity; ferroelectrics; infrared photoelectric detection; Kinetic energy; lateral photovoltaic effect; Nanotechnology; Optical properties; Optoelectronic devices; Photoelectricity; Photovoltaic effect; Potential barriers; Sensitivity
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202105188

As one of the typical transition‐metal dichalcogenides with distinct optical and electrical properties, WS2 exhibits tremendous potential for optoelectronic devices. However, its inherent band gap range limits the application in the infrared region. To overcome this draw‐back and improve the sensitivity, P(VDF‐CTFE) is used as a ferroelectric gate to control the states of WS2/Si junctions and achieve an enhanced infrared photodetection. The polarization electric field not only broadens the range of absorption wavelength (405–1550 nm) but also greatly promotes the sensitivity of lateral photovoltaic effect (LPE) (from 198.6 to 503.2 mV mm−1). This phenomenon is attributed to the reduction of WS2 band gap and the change of potential barrier at the interface of the junction. Meanwhile, the response speed is improved significantly due to the increase of carrier initial kinetic energy. This new scheme for ferroelectric tuned LPE opens up a way to realize high‐sensitivity, ultrafast, and stable infrared photodetection.
P(VDF‐CTFE) is used as a ferroelectric gate to control the states of WS2/Si junction and it achieves an enhanced infrared lateral photovoltiac effect. The polarization electric field not only broadens the range of absorption wavelength but also greatly promotes sensitivity and response speed. This ferroelectric‐tuned WS2/Si device has great potential application in high‐performance, ultra‐fast, super‐sensitive near‐infrared photodetectors.