Bolometric Effect in Bi₂ O₂ Se Photodetectors

Bi₂ O₂ Se 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 Bi₂ O₂ Se 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 Bi₂ O₂ Se 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 Bi₂ O₂ Se photodetectors under time evolution after light excitation. Moreover, the Bi₂ O₂ Se 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 Bi₂ O₂ Se layered materials.