High response and broadband photodetection by monolayer MoSe2 with vanadium doping and Mo vacancies

• Published in: Applied surface science Vol. 564; p. 150399
• Main Authors: Zhao, Yanfeng, Ren, Yuehong, Ó Coileáin, Cormac, Li, Juncheng, Zhang, Duan, Arora, Sunil K., Jiang, Zhaotan, Wu, Han-Chun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.10.2021
• Subjects: Broadband Photodetector; Electrical properties; Optical properties; Photoresponsivity; V doped MoSe2; V doped MoSe2; Electrical properties; Photoresponsivity; Optical properties; Broadband Photodetector
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2021.150399

[Display omitted] •DFT simulations of bandgap engineering of MoSe2, by vacancy and V substitution.•XPS, AFM and Raman characterisation of CVD synthesised MoSe2 to VSe2.•Electrical characterisation of FETs show n- to p-type semiconductor transition.•High broadband responsivity detection achieved for highly doped MoSe2.•Enhanced photo-detection by electrical gating 2800 mA W−1 at 2240 nm and −80 V. Recently, the design of broadband photodetectors based on 2D materials has been a subject of great attention. However, it remains a challenge to achieve both broadband detection and high responsivity for monolayer transition metal dichalcogenide based photodetectors due to the larger band gaps and limited absorption at monolayer thickness. Based on density functional theory calculations, we confirmed that a combination of vanadium substitution doping and Mo vacancies not only decrease the band gap but also enhance the light absorption of monolayer molybdenum diselenide. We also synthesized MoSe2 with both V substitution doping and Mo vacancies by chemical vapor deposition and investigated the electrical and photoelectrical properties. Field effect transistor devices based on the materials showed a transition from n- to p-type characteristics and improved carrier mobility with increasing V concentration. Moreover, photodetectors based on monolayer MoSe2 with 6% V and Mo vacancies displayed a broadband spectral response from 365 nm to 2240 nm, and the responsivity reached 9700 mA W−1 and 2800 mA W−1 at 520 nm and 2240 nm, respectively. Our findings may be useful for designing monolayer transition metal dichalcogenide photodetectors with high responsivities in the infrared region.