▎ 摘　　要

This report describes high-responsivity, long-wavelength infrared graphene photodetectors operating at room temperature, that are based on the photogating effect. Photogating is enhanced by a pyroelectric effect in the lithium niobium oxide (LiNbO3) substrate due to heat generation as a result of radiation absorption by a SiN layer on the substrate. This significantly modulates the back-gate voltage, and increases the photoresponse by a factor of approximately 600. Switching of the charge carrier type in the graphene is observed in response to higher light intensities. The pronounced modulation of the photogating voltage changes the carrier type of graphene. (C) 2019 The Japan Society of Applied Physics