Chip-integrated van der Waals PN heterojunction photodetector with low dark current and high responsivity

Abstract

Two-dimensional materials are attractive for constructing high-performance photonic chip-integrated photodetectors because of their remarkable electronic and optical properties and dangling-bond-free surfaces. However, the reported chip-integrated two-dimensional material photodetectors were mainly implemented with the configuration of metal-semiconductor-metal, suffering from high dark currents and low responsivities at high operation speed. Here, we report a van der Waals PN heterojunction photodetector, composed of p-type black phosphorous and n-type molybdenum telluride, integrated on a silicon nitride waveguide. The built-in electric field of the PN heterojunction significantly suppresses the dark current and improves the responsivity. Under a bias of 1 V pointing from n-type molybdenum telluride to p-type black phosphorous, the dark current is lower than 7 nA, which is more than two orders of magnitude lower than those reported in other waveguide-integrated black phosphorus photodetectors. An intrinsic responsivity up to 577 mA W−1 is obtained. Remarkably, the van der Waals PN heterojunction is tunable by the electrostatic doping to further engineer its rectification and improve the photodetection, enabling an increased responsivity of 709 mA W−1. Besides, the heterojunction photodetector exhibits a response bandwidth of ~1.0 GHz and a uniform photodetection over a wide spectral range, as experimentally measured from 1500 to 1630 nm. The demonstrated chip-integrated van der Waals PN heterojunction photodetector with low dark current, high responsivity and fast response has great potentials to develop high-performance on-chip photodetectors for various photonic integrated circuits based on silicon, lithium niobate, polymer, etc.

Efficient Avalanche Photodiodes with a WSe2/MoS2 Heterostructure via Two-Photon Absorption

“…For the past decade, two-dimensional (2D) materials-based photodetector technologies have shown impressive progress with respect to key performance metrics including responsivity and speed. − Recently, infrared photodetection using 2D materials has been gaining much attention for various applications such as infrared sensing and imaging, high-speed optical communications, and integrated photonics applications. − In particular, black phosphorus with small and tunable energy bandgaps has exhibited great promise for efficient infrared photodetection, but its poor stability originated from chemical degradation in ambient conditions that hampers efficient and long-lasting stable photodetection for optoelectronic applications. − The stable 2D materials such as MoS 2 , WS 2 , and WSe 2 are highly desirable for infrared photodetection. However, most of these materials have bandgaps in the visible region, preventing them from being sensitive to infrared photons. − A multiphoton absorption process can enable such 2D materials with large bandgaps to detect infrared photons .…”

High‐Speed Photodetectors on Silicon Photonics Platform for Optical Interconnect

“…On the other hand, for some 2D material-based PDs, a zero dark current is possible since they can work at zero bias voltage. [45,231,259] Therefore, the combination of different types of materials is also a possible solution.…”

Integration of Black Phosphorus Photoconductors with Lithium Niobate on Insulator Photonics

“…The development of new photonic integrated circuit (PIC) technologies is essential to the continued advancement of PIC platforms including silicon, [15] silicon nitride, [19] and chalcogenide glass, [20] although to the best of our knowledge remains untested with LNOI. Lithium niobate on insulator is a relatively new PIC technology combining the exceptional optical properties of lithium niobate, including high-speed electro-optic switching, strong χ (2) nonlinearity and wide bandgap, with high index contrast for compact circuits.…”