Efficient graphene in-plane homogeneous p-n-p junction based infrared photodetectors with low dark current

Abstract

Graphene-based photodetectors have drawn a large amount of interests owing toits wide spectral response, however, the high dark current greatly limitstheir applications. In this study, we develop an efficient graphenein-plane homogeneous p-n-p junction based infrared (IR) photodetector withgreatly reduced dark current. The devices with p-n-p junctions exhibitexcellent photoresponse to 1.0$\\sim~$4.0 $\\mu~$m IR light illumination withultra-low dark current at the order of $\\sim~$10$^{~-~9}$ A in double p-n-pjunctions and 10$^{~-~13}$ A in three p-n-p junctions based photodetector,which is three and seven orders of magnitude lower than pristine graphenephototransistors, respectively. The excellent IR photodetection capabilitiescould be attributed to the synergistic effects of in-plane photovoltaiceffects as well as the photogating effects induced carrier injection fromthe silicon substrate. Our results suggest intriguing potential of graphenein-plane p-n-p junctions for applications in high-performance IRphotodetectors.