Broadband Van‐der‐Waals Photodetector Driven by Ferroelectric Polarization

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-01, Vol.20 (3), p.e2305045-n/a
• Main Authors: Kim, Sungjun, Lee, Sunghun, Oh, Seyong, Lee, Kyeong‐Bae, Lee, Je‐Jun, Kim, Byeongchan, Heo, Keun, Park, Jin‐Hong
• Format: Article
• Language: English
• Subjects: Broadband; broadband photodetectors; Conduction bands; Dark current; Dipoles; Energy gap; Ferroelectric materials; ferroelectric polarization; Ferroelectricity; Heterojunctions; Industrial applications; Interlayers; P(VDF‐TrFE); Photometers; rhenium disulfide; Ternary alloys; tungsten diselenide; Valence band; vdW heterojunction; Vinylidene; Vinylidene fluoride
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202305045

The potential for various future industrial applications has made broadband photodetectors beyond visible light an area of great interest. Although most 2D van‐der‐Waals (vdW) semiconductors have a relatively large energy bandgap (>1.2 eV), which limits their use in short‐wave infrared detection, they have recently been considered as a replacement for ternary alloys in high‐performance photodetectors due to their strong light‐matter interaction. In this study, a ferroelectric gating ReS2/WSe2 vdW heterojunction‐channel photodetector is presented that successfully achieves broadband light detection (>1300 nm, expandable up to 2700 nm). The staggered type‐II bandgap alignment creates an interlayer gap of 0.46 eV between the valence band maximum (VBMAX) of WSe2 and the conduction band minimum (CBMIN) of ReS2. Especially, the control of poly(vinylidene fluoride‐trifluoroethylene) (P(VDF‐TrFE)) ferroelectric dipole polarity for a specific wavelength allows a high photoresponsivity of up to 6.9 × 103 A W−1 and a low dark current below 0.26 nA under the laser illumination with a wavelength of 405 nm in P‐up mode. The achieved high photoresponsivity, low dark current, and full‐range near infrared (NIR) detection capability open the door for next‐generation photodetectors beyond traditional ternary alloy photodetectors. A ferroelectric gating photodetector is developed with a ReS2/WSe2 vdW heterojunction‐channel. This device effectively detects a wide range of light wavelengths, including broadband light exceeding 1300 nm and expandable up to 2700 nm. The successful detection is attributed to the staggered type‐II bandgap alignment, which results in an interlayer gap of 0.46 eV. By controlling the polarity of the P(VDF‐TrFE) ferroelectric dipole for a specific wavelength, both high photoresponsivity (>6.9 × 103 A W−1) and low dark current (