Enhancing UV-C Photoelectron Lifetimes for Avalanche-like Photocurrents in Carbon-Doped Bi3O4Cl Nanosheets

Interlayer electric fields in two-dimensional (2D) materials create photoelectron protecting barriers useful to mitigate electron-hole recombination. However, tuning the interlayer electric field remains challenging. Here, carbon-doped Bi3O4Cl (C:Bi3O4Cl) nanosheets are synthesized using a gas phase protocol, and n-type carriers are acquired as confirmed by the transconductance polarity of nanosheet field effect transistors. Thin C:Bi3O4Cl nanosheets show excellent 266 nm photodetector figures of merit, and an avalanche-like photocurrent is demonstrated. Decaying behaviors of photoelectrons pumped by a 266 nm laser pulse (266 nm photoelectrons) are observed using transient absorption spectroscopy, and a significant 266 nm photoelectron lifetime quality in C:Bi3O4Cl is presented. Built C:Bi3O4Cl models suggest that the interlayer electric field can be boosted by two different carbon substitutions at the inner and outer bismuth sites. This work reports a facile approach to increase the interlayer electric field in Bi3O4Cl for future UV-C photodetector applications.