High‐Performance Photodetectors Based on Suspended Ultralong CNTs‐MoS₂ Heterojunction Networks

Abstract

Carbon nanotubes (CNTs) are promising candidates for photodetectors due to their excellent electrical and optical properties. However, the strong binding energy of excitons, structural defects, and short lengths of CNTs seriously limited the full utilization of the inherently extraordinary properties of CNTs in photodetector construction. Herein, a new strategy is designed for fabricating high‐performance VIS and NIR photodetectors based on suspended ultralong CNTs‐MoS2 heterojunction networks. The MoS2 layers are directly grown on suspended ultralong CNT bundles (s‐UCNTBs). The suspended and defect‐free structures of s‐UCNTBs ensure rapid heat dissipation and perfectly avoid the electron‐phonon interactions from substrates. The interfaces between s‐UCNTBs and MoS2 effectively improve the generation and transport of photogenerated carriers, thus remarkably enhancing the photodetection performance of s‐UCNTBs‐MoS2 networks. The s‐UCNTBs‐MoS2 networks‐based photodetectors exhibit a high responsivity (8.51 A W−1), a high detectivity (3.74 × 1011 cm Hz1/2 W−1), an ultrafast response speed (30 µs/40 µs for response/decay), and a broad detection range (405–1064 nm), far outperforming the most reported carbon materials‐based photodetectors. Moreover, the s‐UCNTBs‐MoS2 photodetector exhibits good structural and performance stability after being kept in ambient conditions for more than 200 days. This work provides a reliable way to construct high‐performance CNTs‐based devices via structural design.