MoSe2/WS2 heterojunction photodiode integrated with a silicon nitride waveguide for near infrared light detection with high responsivity
Rivka Gherabli, S.R.K. Chaitanya Indukuri, Roy Zektzer, Christian Frydendahl, Uriel Levy
Abstract
Abstract We demonstrate experimentally the realization and the characterization of a chip-scale integrated photodetector for the near-infrared spectral regime based on the integration of a MoSe 2 /WS 2 heterojunction on top of a silicon nitride waveguide. This configuration achieves high responsivity of ~1 A W −1 at the wavelength of 780 nm (indicating an internal gain mechanism) while suppressing the dark current to the level of ~50 pA, much lower as compared to a reference sample of just MoSe 2 without WS 2 . We have measured the power spectral density of the dark current to be as low as ~1 × 10 −12 A Hz −0.5 , from which we extract the noise equivalent power (NEP) to be ~1 × 10 −12 W Hz −0.5 . To demonstrate the usefulness of the device, we use it for the characterization of the transfer function of a microring resonator that is integrated on the same chip as the photodetector. The ability to integrate local photodetectors on a chip and to operate such devices with high performance at the near-infrared regime is expected to play a critical role in future integrated devices in the field of optical communications, quantum photonics, biochemical sensing, and more.