High‐Performance Infrared Photodetectors Driven by Interlayer Exciton in a Van Der Waals Epitaxy Grown HfS₂/MoS₂ Vertical Heterojunction

Abstract

The van der Waals (vdW) heterojunctions of transition metal dichalcogenides (TMDCs) provide an advanced platform for interlayer exciton generation to detect the exceeding cutoff wavelengths of individual TMDCs. Herein, the first demonstration of high‐performance infrared (IR) photodetectors driven by interlayer excitons and based on HfS2/MoS2 vdW heterojunctions grown by chemical vapor deposition is presented. HfS2 exhibits selective growth only on MoS2, establishing a vertical heterojunction that effectively generates interlayer excitons. The synthesized HfS2/MoS2 vertical heterojunction with type‐II band alignment exhibits a low interlayer bandgap and a significantly large interface area, enabling highly efficient IR detection. Moreover, the built‐in potential in HfS2/MoS2 plays a pivotal role in the outstanding photoresponse by suppressing the dark current and providing gradient band bending for the interlayer exciton‐induced photocarriers to drift toward each electrode. The HfS2/MoS2 photodetector exhibits remarkable performance, achieving a detectivity (D*) of ≈7 × 1013 Jones at 1550 nm, D* of ≈2 × 1014 Jones at 980 nm, and fast response time of 60 µs, surpassing previously reported 2D photodetectors. Overall, the successful demonstration of a photodetector based on vdW epitaxial HfS2/MoS2 paves the way for the advancement of large‐scale high‐performance IR sensors.

High Sensitive and Stable UV–Vis Photodetector Based on MoS2/MoO3 vdW Heterojunction

“…On this basis, when the light is applied, the intrinsic current of the MoO 3 PD is higher, resulting in a higher photocurrent. In contrast, the MoS 2 /MoO 3 vdW PD exhibits reduced I dark (dark current) and I light (photocurrent) values because of the presence of an energy barrier that restricts the electron flow at the interface between MoS 2 and MoO 3 , thereby minimizing the dark current to 2.0 × 10 –10 A . It is worth noting that the I light / I dark of MoS 2 /MoO 3 vdW PD exceeds the MoO 3 PD by more than 10 times.…”

“…Because of its strong mechanical properties and high carrier mobility, graphene has great application potential in the field of optoelectronic devices. , However, due to the characteristics of the zero band gap and weak light absorption rate of graphene, the PDs prepared by graphene have high dark current and low responsivity . 2D black phosphorus (BP) has a hole mobility of up to 1000 cm 2 V –1 s –1 and a tunable band gap, but its instability in the environment is the main reason limiting its further development. , Transition-metal dichalcogenides (TMDs) not only have the advantages of high mobility, high photosensitivity, high transparency, and adjustable band gap but also have high thermal and chemical stability, which has great application potential in the next generation of ultrathin electronic devices. − Most of the 2D semiconductor materials discovered so far are narrow band gaps, such as BP, TMDs, GaSe, GaS, and FePSe 3 , which limit the potential application of devices in UV detection. Recently, some scientists have used 2D materials and 3D wide-bandgap semiconductor materials to construct heterojunctions to improve the UV detection capability of devices, such as Mo x Re 1– x S 2 /GaN, TiO 2 /V 2 CT x , PtSe 2 /β-Ga 2 O 3 , and ZnS/MoS 2 .…”

Edge-Rich 3D Structuring of Metal Chalcogenide/Graphene with Vertical Nanosheets for Efficient Photocatalytic Hydrogen Production

“…Hydrogen has been extensively studied as an ideal clean energy source to replace conventional fossil fuels. Photocatalytic and photoelectrochemical (PEC) hydrogen generation by water splitting using sunlight is a promising strategy to produce hydrogen fuel by harvesting solar energy for energy storage use. − Transition metal compounds or Transition metal chalcogenides (TMDs), which are two-dimensional (2D) layered structures, have revitalized an upsurge in research interest because of exceptional electronic, photoelectric, and energy harvesting performance. − Among these TMDs, molybdenum disulfide (MoS 2 ) and tungsten disulfide (WS 2 ) have recently attracted considerable attention as a suitable material for cocatalysis or photocatalytic hydrogen generation due to their relatively high mobility (a few hundred cm 2 V –1 s –1 ), superior catalytic properties, and an adequate bandgap that is compatible with sunlight. − …”