Submillimeter 2D Bi2Se3 Flakes toward High‐Performance Infrared Photodetection at Optical Communication Wavelength

• Published in: Advanced functional materials 2018-08, Vol.28 (33), p.n/a
• Main Authors: Wang, Fakun, Li, Leigang, Huang, Wenjuan, Li, Liang, Jin, Bao, Li, Huiqiao, Zhai, Tianyou
• Format: Article
• Language: English
• Subjects: Bi2Se3; Communication; Energy gap; Flakes; Infrared detectors; infrared optical communication wavelength; Materials science; Military applications; Military communications; Morphology; Nucleation; Optical communication; Optoelectronics; photodetectors; Photometers; Quantum efficiency; Remote sensing; Stability; topological insulators
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201802707

Infrared detection at optical communication wavelength is of great significance because of their diverse commercial and military communication applications. The layered Bi2Se3 with a narrow band gap of 0.3 eV is regarded as a promising candidate toward high‐performance terahertz to infrared applications. However, the controllable synthesis of large‐size ultrathin Bi2Se3 flakes remains a challenge owing to complex nucleation process and infrared telecommunication photodetectors based on Bi2Se3 flakes are rarely reported. Here, large size (submillimeter: 0.2–0.4 mm in lateral dimensions) and ultrathin (thickness: 3 nm to few nanometers) 2D Bi2Se3 flakes with high crystal quality are obtained by suppressing the nucleation density. More importantly, back‐gate field‐effect transistor based on Bi2Se3 flake exhibits an ultrahigh on/off current ratio of 106 and competitive mobility of 39.4 cm2 V−1 s−1. Moreover, excellent on/off ratio of 972.5, responsivity of 23.8 A W−1, and external quantum efficiency of 2035% are obtained from Bi2Se3‐based photodetector at 1456 nm in the E‐band of the telecommunication range. With controlled morphology and excellent photoresponse performance, the Bi2Se3 photodetector shows great potential in the optoelectronic field including communications, military, and remote sensing. The synthesis of submillimeter atomically thin Bi2Se3 flakes via van der Waals epitaxy is presented. Impressively, the optical communication wavelength sensors based on the Bi2Se3 flakes exhibit an on/off ratio of 972.5, responsivity of 23.8 A W−1, and an external quantum efficiency of 2035% at 80 K.