title: High-Responsivity Graphene-Boron Nitride Photodetector and Autocorrelator in a Silicon Photonic Integrated Circuit.
abstract: Graphene and other two-dimensional (2D) materials have emerged as promising materials for broadband and ultrafast photodetection and optical modulation. These optoelectronic capabilities can augment complementary metal-oxide-semiconductor (CMOS) devices for high-speed and low-power optical interconnects. Here, we demonstrate an on-chip ultrafast photodetector based on a two-dimensional heterostructure consisting of high-quality graphene encapsulated in hexagonal boron nitride. Coupled to the optical mode of a silicon waveguide, this 2D heterostructure-based photodetector exhibits a maximum responsivity of 0.36 A/W and high-speed operation with a 3 dB cutoff at 42 GHz. From photocurrent measurements as a function of the top-gate and source-drain voltages, we conclude that the photoresponse is consistent with hot electron mediated effects. At moderate peak powers above 50 mW, we observe a saturating photocurrent consistent with the mechanisms of electron-phonon supercollision cooling. This nonlinear photoresponse enables optical on-chip autocorrelation measurements with picosecond-scale timing resolution and exceptionally low peak powers.
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Ren-Jye
authors.initials: RJ
authors.lastname: Shiue
authors.affiliation: Department of Mechanical Engineering, Columbia University , New York, New York 10027, United States.
authors.forename: Yuanda
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Yifei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Cheng
authors.initials: C
authors.lastname: Peng
authors.affiliation: Department of Mechanical Engineering, Columbia University , New York, New York 10027, United States.
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Robertson
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Dmitri K
authors.initials: DK
authors.lastname: Efetov
authors.affiliation: IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, United States.
authors.forename: Solomon
authors.initials: S
authors.lastname: Assefa
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Castelldefels, Barcelona, Spain.
authors.forename: Frank H L
authors.initials: FH
authors.lastname: Koppens
authors.affiliation: Department of Mechanical Engineering, Columbia University , New York, New York 10027, United States.
authors.forename: James
authors.initials: J
authors.lastname: Hone
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Dirk
authors.initials: D
authors.lastname: Englund
keywords: autocorrelators; boron nitride; graphene; optoelectronics; photodetectors; silicon photonics