摘要
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.
