Self-Powered Broadband Photodetector Based on Single-Walled Carbon Nanotube/GaAs Heterojunctions

Van der Waals (vdW) heterojunctions between single-walled carbon nanotubes (SWCNTs) and GaAs are potential candidates for optoelectronic devices owing to their direct bandgap, high carrier mobility, diffusion-free atomically sharp interface, and flexible device structures. The existence of mixed-chirality SWCNTs suppresses the charge separation and transportation of photoexcited carriers at the interface. Herein, we demonstrate a self-powered broadband photodetector by combining n-type GaAs with a (6, 5)-enriched semiconducting SWCNT film. The experimental results show that the device exhibits a broadband photoelectric response spectrum from visible (405 nm) to near-infrared (1064 nm). Under 780 nm illumination, a high responsivity of 274 mA W–1 and detectivity of 7.6 × 1012 Jones can be achieved with a response/recovery time of 1.41/0.27 ms at zero bias. The photoelectric performance is mainly attributed to the enhanced separation efficiency of the photoexcited carriers due to the formation of vdW heterojunctions. Our findings open up the opportunities for highly sensitive self-powered photodetectors.