High‐Efficiency Infrared Sensing with Optically Excited Graphene‐Transition Metal Dichalcogenide Heterostructures

Abstract

Binary van der Waals heterostructures of graphene (Gr) and transition metal dichalcogenide (TMDC) have evolved as a promising candidate for photodetection with very high responsivity due to the separation of photo‐excited electron–hole pairs across the interface. The spectral range of optoelectronic response in such hybrids has so far been limited by the optical bandgap of the light absorbing TMDC layer. Here, the bidirectionality of interlayer charge transfer is utilized for detecting sub‐band gap photons in Gr‐TMDC heterostructures. A Gr/MoSe2 heterostructure sequentially driven by visible and near infra‐red (NIR) photons is employed, to demonstrate that NIR induced back transfer of charge allows fast and repeatable detection of the low energy photons (less than the optical band gap of the TMDC layer). This mechanism provides photoresponsivity as high as ≈3000 A W−1 close to the communication wavelength. The experiment provides a new strategy for achieving highly efficient photodetection over a broad range of energies beyond the spectral bandgap with the 2D semiconductor family.

2D van der Waals Heterostructure with Tellurene Floating-Gate for Wide Range and Multi-Bit Optoelectronic Memory

“…As a result, the readout current of the device was smaller when we applied an NIR laser pulse (980 nm) compared to that when we applied the VIS laser pulse (532 nm). To rule out the other effects for the device response in the NIR regime, such as midgap trap states in TMDs, , we fabricated a single ReS 2 /hBN device and measured its light response with 850 nm laser excitation, as depicted in Figure S13. The ReS 2 /hBN device without a 2D Te FG exhibited an extremely small response to the 850 nm laser with an I on / I off ratio of less than 1.5.…”

High-Responsivity and Broadband MoS2 Photodetector Using Interfacial Engineering

“…Developing high-performance and broadband photodetectors is significant to military defense, optical communication, environmental monitoring, biomedicine, and other fields. , Two-dimensional (2D) materials have attracted more and more attention due to the controllability of their dimensions in the longitudinal direction and their potential applications in future electronic and optoelectronic devices, especially photodetectors. − Molybdenum disulfide (MoS 2 ), one of the most representative 2D materials, has a layered structure composed of S–Mo–S structural units combined with van der Waals forces. The electronic band gap of MoS 2 increases from 1.2 to 1.8 eV and transits from indirect to direct as the number of stacking layers decreases from bulk to monolayer. , Furthermore, MoS 2 possesses high carrier mobility (up to 200 cm 2 V –1 s –1 ), a high current on/off ratio (as high as 10 8 ), and strong visible wavelength absorption .…”

“…Developing high-performance and broadband photodetectors is significant to military defense, optical communication, environmental monitoring, biomedicine, and other fields. 1,2 Two-dimensional (2D) materials have attracted more and more attention due to the controllability of their dimensions in the longitudinal direction and their potential applications in future electronic and optoelectronic devices, especially photodetectors. 3−5 Molybdenum disulfide (MoS 2 ), one of the most representative 2D materials, has a layered structure composed of S−Mo−S structural units combined with van der Waals forces.…”

Monolayer Graphene–MoSSe van der Waals Heterostructure for Highly Responsive Gate-Tunable Near-Infrared-Sensitive Broadband Fast Photodetector

“…16 Making vdW heterostructures of TMDCs and graphene is a popular strategy to overcome the inherent limitations of graphene and TMDCs for use in optoelectronics. 17 Due to the high optical absorption coefficient, TMDC produces a large number of photogenerated carriers, which are quickly transferred to the high-carrier-mobility graphene layer that acts as the channel for charge flow. Thus, the sensitivity of the heterostructure device increases many-fold compared to those of devices with the individual materials.…”