Bolometric Effect in Bi2O2Se Photodetectors

Bi2O2Se is emerging as a photosensitive functional material for optoelectronics, and its photodetection mechanism is mostly considered to be a photoconductive regime in previous reports. Here, the bolometric effect is discovered in Bi2O2Se photodetectors. The coexistence of photoconductive effect and bolometric effect is generally observed in multiwavelength photoresponse measurements and then confirmed with microscale local heating experiments. The unique photoresponse of Bi2O2Se photodetectors may arise from a change of hot electrons during temperature rises instead of photoexcited holes and electrons. Direct proof of the bolometric effect is achieved by real-time temperature tracking of Bi2O2Se photodetectors under time evolution after light excitation. Moreover, the Bi2O2Se bolometer shows a high temperature coefficient of resistance (-1.6% K-1), high bolometric coefficient (-31 nA K-1), and high bolometric responsivity (>320 A W-1). These findings offer a new approach to develop bolometric photodetectors based on Bi2O2Se layered materials.