Uncooled Graphene Infrared Detectors Enabled by Pyroelectric Photogating for Human Radiation Perception

Abstract

Uncooled long-wave infrared (LWIR) detectors substantially facilitate the advancement of miniaturized, highly integrated, and lightweight human radiation perception technology. However, constrained by materials and device structures, the progress of conventional LWIR detectors has stagnated in efficiently detecting weak human radiation at room temperature. Herein, a pyroelectric photogating-based uncooled LWIR detector with a graphene-Al₂O₃-LiNbO₃ hybrid structure is proposed for highly sensitive human radiation detection. The device leverages the polarized charge of LiNbO₃ to modulate the conductance carriers in graphene, thereby achieving an amplified photoresponse in the LWIR range of 8 to 11 µm. Notably, at room temperature, the device exhibits a superior responsivity of 48 A W⁻¹ under blackbody radiation, surpassing the performance of previous 2D materials-based LWIR detectors. Remarkably, it can identify the radiation signals of a human finger, a feat previously considered challenging for devices relying on graphene or other 2D materials. These results reveal the potential of pyroelectric photogating and provide valuable insights for developing high-sensitivity, uncooled photodetectors.