WSe2 Heterostructures Research Articles

Enhanced Optoelectronic Performance of p-WSe2/Re0.12W0.42Mo0.46S2 Heterojunction.

Stacking of van der Waals (vdW) heterostructures and chemical element doping have emerged as crucial methods for enhancing the performance of semiconductors. This study proposes a novel strategy for modifying heterostructures by codoping MoS2 with two elements, Re and W, resulting in the construction of a RexWyMo1-x-yS2/WSe2 heterostructure for the preparation of photodetectors. This approach incorporates multiple strategies to enhance the performance, including hybrid stacking of materials, type-II band alignment, and regulation of element doping. As a result, the RexWyMo1-x-yS2/WSe2 devices demonstrate exceptional performance, including high photoresponsivity (1550.22 A/W), high detectivity (8.17 × 1013 Jones), and fast response speed (rise/fall time, 190 ms/1.42 s). Moreover, the ability to tune the band gap through element doping enables spectral response in the ultraviolet (UV), visible light, and near-infrared (NIR) regions. This heterostructure fabrication scheme highlights the high sensitivity and potential applications of vdW heterostructure (vdWH) in optoelectronic devices.

Carbon Mediated Multifunctional Sb2Se3–WSe2 Heterostructure Nanofiber Facilitates Rapid and Stable Na+ Transport

AbstractAlloying metal selenides as advanced anode materials for sodium‐ion devices requires overcoming the challenges of high diffusion energy barriers and large volume expansion at high‐power densities. The typical dealloying process is difficult to trigger under fast kinetics, leading to limited capacity utilization. Here, Sb/W‐hybridization precursor is synthesized by one‐step reaction, followed by electrostatic spinning strategy to achieve a localized domain‐limiting effect. Finally, the carbon mediated Sb2Se3–WSe2 heterostructure nanofiber (SbWSe/C/NF) are obtained after carbonization/selenization process. Physical characterization and theoretical calculations reveal that the SbWSe/C/NF‐500 has a heterogeneous structure and abundant edge carbon defects, facilitating rapid Na+ transfer from exterior to interior. Furthermore, compared with the Sb2Se3/C monomer, the SbWSe/C heterostructure shows a significant dealloying reaction at high current densities, enhancing capacity utilization. Resultantly, the Na half‐cell with SbWSe/C/NF‐500 electrode demonstrates excellent rate capability and a high specific capacity of 553.7 mA h g−1 after 250 cycles at 2 A g−1. Meanwhile, the assembled sodium‐ion capacitor exhibits 80.83% capacity retention after 8000 cycles at 3800 W kg−1. The structure design strategy of cationic heterostructures with dual‐carbon introduction provides a reference for developing high‐power anodes.

Highly Sensitive Broadband Polarized Photodetector Based on the As0.6P0.4/WSe2 Heterostructure toward Imaging and Optical Communication Application.

Polarization-sensitive photodetectors based on two-dimensional anisotropic materials still encounter the issues of narrow spectral coverage and low polarization sensitivity. To address these obstacles, anisotropic As0.6P0.4 with a narrow band gap has been integrated with WSe2 to construct a type-II heterostructure, realizing a high-performance polarization-sensitive photodetector with broad spectral range from 405 to 2200 nm. By operating in photovoltaic mode at zero bias, the device shows a very low dark current of ∼0.02 picoampere, high responsivity of 492 m A/W, and high photoswitching ratio of 6 × 104, yielding a high specific detectivity of 1.4 × 1012 Jones. The strong in-plane anisotropy of As0.6P0.4 endows the device with a capability of polarization-sensitive detection with a high polarization ratio of 6.85 under a bias voltage. As an image sensor and signal receiver, the device shows great potential in imaging and optical communication applications. This work develops an anisotropic vdW heterojunction to realize polarization-sensitive photodetectors with wide spectral coverage, fast response, and high sensitivity, providing a new candidate for potential applications of polarization-resolved electronics and photonics.

Synthesis of NbSe2/Bilayer Nb‐Doped WSe2 Heterostructure from Exfoliated WSe2 Flakes

Forming heterostructures of 2D metals and semiconductors using chemical vapor deposition (CVD) has significant potential to effectively reduce contact resistance in electronic devices. However, semiconducting transition metal dichalcogenide (TMD) layers in metal–semiconductor heterostructures are currently restricted to monolayers despite the superior mobility and density of states in bilayer TMDs. Herein, NbSe2/bilayer Nb‐doped WSe2 metal/semiconductor heterostructure from exfoliated WSe2 flakes are synthesized first. The exfoliated WSe2 bulk crystals on an Nb‐coated substrate are heated to 950 °C under a flow of selenium vapor, and then the NbSe2/bilayer Nb‐doped WSe2 heterostructures are formed. Statistics on the number of Nb‐doped WSe2 layers grown on a 1 cm × 1 cm CVD substrate shows that 65% of the Nb‐doped WSe2 layers are grown as bilayers. X‐ray photoelectron spectroscopy, optical microscopy, and transmission electron microscopy clearly clarify the number of Nb‐doped WSe2 layers and heterostructure of NbSe2/bilayer Nb‐doped WSe2. Electrical measurements using Cr contacts show that bilayer Nb‐doped WSe2 displays 7‐ and 10‐times higher mobility and on/off ratio than monolayer Nb‐doped WSe2. The mobility and on/off ratio are further doubled in NbSe2/bilayer Nb‐doped WSe2 contact compared to Cr/bilayer Nb‐doped WSe2 contact, attributed to a clean interface in vertical stack heterostructure, enhancing electrical performance.

Enhanced Modulation Bandwidth by Integrating 2D Semiconductor and Quantum Dots for Visible Light Communication

Light‐emitting devices present a tremendous potential for visible light communication (VLC) due to their dual functionality as both communication and lighting devices. Herein this study, the significant enhancement in VLC modulation bandwidth by integrating two‐dimensional (2D) semiconductor and quantum dots (QDs) emitter is reported. Generally, the modulation bandwidth of CdSe‐based QDs is limited to only less than 25 MHz; however, with the proposed hybrid emitter, a maximum modulation bandwidth of 130 MHz for CdSe/ZnS QDs emitter is able to be achieved. The WSe2 monolayer is integrated into an Au–nanorod–decorated CdSe/ZnS QDs emitter to achieve high modulation performance. The modulation bandwidth of the hybrid QD–Au–WSe2 emitter (130 MHz) is found to be higher than those of the pristine QDs and QD–WSe2 heterostructure without Au nanorods (79 and 91 MHz, respectively). A significant increase is observed in the transition rate of QDs excitons when they are integrated with Au nanorods and WSe2 monolayer, which is substantiated by a reduction in average carrier lifetime from time‐resolved photoluminescence analysis. This approach and the findings open an opportunity to apply 2D semiconductors into the next‐generation miniature VLC devices, for high‐speed optical communications.

Self-driven Vis-NIR broadband photodetector based on nano-hedge-like MoS2/WSe2 heterostructure

TMDC heterostructures provide alternative bases for optoelectronic devices besides conventional Schottky devices. With the continued expansion of the modern semiconductor industry, self-powered devices have emerged as an integral part of electronic and optoelectronic equipments. This work reports a unique seamless nano-hedge (nh) like morphology of MoS2 deposited on WSe2 film to form nh-MoS2/WSe2 heterostructure as a self-powered photodetector with a broad spectral range from visible to NIR. The developed heterostructure exhibits a very high responsivity of 900 mAW-1 when illuminated by 860 nm under zero bias (self-powered mode). In addition, the device also shows a high responsivity of 177 mAW-1, 271 mAW-1, and 506 mAW-1 for illumination of 532 nm, 625 nm light, and 950 nm, respectively, at zero applied bias. With low noise equivalent power of 2.6 × 10-14 WHz1/2 and ultra-high responsivity of 2.6 × 104 mAW-1 in photoconductive mode at 860 nm light irradiation, the device exhibits extremely high external quantum efficiency of 6.29 × 103%. Further, the device also displays detectivity of 5 × 1011 Jones, an LDR value of 26 dB, with a fast response time of 15 ms. Developing a broadband photodetector based on nh-MoS2/WSe2 heterostructure opens the route for highly responsive, self-powered future optoelectronic devices.

Excitons in mesoscopically reconstructed moiré heterostructures

Moiré effects in vertical stacks of two-dimensional crystals give rise to new quantum materials with rich transport and optical phenomena that originate from modulations of atomic registries within moiré supercells. Due to finite elasticity, however, the superlattices can transform from moiré-type to periodically reconstructed patterns. Here we expand the notion of such nanoscale lattice reconstruction to the mesoscopic scale of laterally extended samples and demonstrate rich consequences in optical studies of excitons in MoSe2–WSe2 heterostructures with parallel and antiparallel alignments. Our results provide a unified perspective on moiré excitons in near-commensurate semiconductor heterostructures with small twist angles by identifying domains with exciton properties of distinct effective dimensionality, and establish mesoscopic reconstruction as a compelling feature of real samples and devices with inherent finite size effects and disorder. Generalized to stacks of other two-dimensional materials, this notion of mesoscale domain formation with emergent topological defects and percolation networks will instructively expand the understanding of fundamental electronic, optical and magnetic properties of van der Waals heterostructures.

Visualizing interface states in In2Se3-WSe2 monolayer lateral heterostructures

Recent findings of two-dimensional (2D) ferroelectric (FE) materials provide more possibilities for the development of 2D FE heterostructure electronic devices based on van der Waals materials and the application of FE devices under the limit of atomic layer thickness. In this paper, we report the in-situ fabrication and probing of electronic structures of In2Se3–WSe2 lateral heterostructures, compared with most vertical FE heterostructures at present. Through molecular beam epitaxy, we fabricated lateral heterostructures with monolayer WSe2 (three atomic layers) and monolayer In2Se3 (five atomic layers). Type-II band alignment was found to exist in either the lateral heterostructure composed of anti-FE β′-In2Se3 and WSe2 or the lateral heterostructure composed of FE β*-In2Se3 and WSe2, and the band offsets could be modulated by ferroelectric polarization. More interestingly, interface states in both lateral heterostructures acted as narrow gap quantum wires, and the band gap of the interface state in the β*-In2Se3–WSe2 heterostructure was smaller than that in the β′-In2Se3 heterostructure. The fabrication of 2D FE heterostructure and the modulation of interface state provide a new platform for the development of FE devices.

Exploring the Ti2CO2–WSe2 Heterostructure as a Direct Z-Scheme Photocatalyst for Water Splitting: A Non-Adiabatic Study

One of the potential strategies to solve renewable energy shortage is to design low-cost efficient photocatalysts for water splitting to aid hydrogen and oxygen evolution reactions (HER and OER). Two-dimensional (2D) materials like MXenes and transition metal dichalcogenides (TMDs) have caught special attention owing to their unique optical, electrical, and mechanical properties, but come with issues like photocorrosion and poor charge separation. Bilayer vdW heterojunctions of suitable constitutive monolayers are coming up as a potential solution to these hazards, accredited to their tunable band gap and efficient charge separation. In this paper, we have investigated the possibility of Ti2CO2–WX2 (X = S, Se, Te) vdW heterostructures to perform as Z-scheme photocatalysts by employing first-principle density functional calculations, and thereby, the Ti2CO–WSe2 heterostructure has emerged as the most promising material for Z-scheme photocatalysis. Further, excited-state dynamics simulation reveals that the timescales of electron transfer and hole transfer are greater (1.13 and 1.22 ps, respectively) than the maximum time limit of the photogenerated electron–hole recombination (1.0 ps) owing to the weaker non-adiabatic coupling and electron–phonon coupling. This affirms the fact that photogenerated electrons and holes with greater redox ability are preserved to drive the photocatalytic pathway. In addition to that, the free energy calculations associated with the HER and OER processes entail that the processes occur spontaneously on the surface of the heterostructure without any co-catalyst. This establishes the Ti2CO–WSe2 heterostructure as a potential mediator-free direct Z-scheme photocatalyst for overall water splitting.

Vertical MoSe2–WSe2 p-n Heterojunctions Grown by One-Pot Chemical Vapor Deposition for Ultrafast Photodetection

Two-dimensional transition metal dichalcogenides (TMDCs) have been extensively studied in the last decade due to their atomic thin structure and unique optoelectronic properties. In particular, lateral and vertical van der Waals heterostructures by combining different transition metal dichalcogenides (TMDCs) have been studied to develop the potential applications of two-dimensional materials. However, the optical properties are challenging due to the limited quality of TMDCs based heterojunctions. In this work, vertical MoSe2/WSe2 p–n heterojunctions have been synthesized by one-pot chemical vapor deposition (CVD) method. The MoSe2 -WSe2 heterostructure exhibits rectification characteristics of a p-n junction with the rectification ratio of 100 at ±10V bias. The phototransistor based on MoSe2/WSe2 p-n heterojunction shows a photoresponse of visible(638nm). The responsivity can reach up to 20 A/W, and the detectivity is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.5\times 10^{13}$ </tex-math></inline-formula> Jones. Most importantly, the optical response time of the MoSe2/WSe2 p-n heterojunction is as fast as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$28 ~\mu $ </tex-math></inline-formula> s. The results indicate that vertical MoSe2/WSe2 p-n heterojunction could be a prospective candidate for high-performance optoelectronic devices.

Localized interlayer excitons in MoSe2–WSe2 heterostructures without a moiré potential

Interlayer excitons (IXs) in MoSe2–WSe2 heterobilayers have generated interest as highly tunable light emitters in transition metal dichalcogenide (TMD) heterostructures. Previous reports of spectrally narrow (<1 meV) photoluminescence (PL) emission lines at low temperature have been attributed to IXs localized by the moiré potential between the TMD layers. We show that spectrally narrow IX PL lines are present even when the moiré potential is suppressed by inserting a bilayer hexagonal boron nitride (hBN) spacer between the TMD layers. We compare the doping, electric field, magnetic field, and temperature dependence of IXs in a directly contacted MoSe2–WSe2 region to those in a region separated by bilayer hBN. The doping, electric field, and temperature dependence of the narrow IX lines are similar for both regions, but their excitonic g-factors have opposite signs, indicating that the origin of narrow IX PL is not the moiré potential.

Spontaneous heteroassembly of 2D semiconducting van der Waals materials in random solution phase

van der Waals heterostructures (vdWHs), consisting of more than one type of atomically thin 2D crystal layers are emerging platforms for interesting electrical, optical, and catalytic applications. High yield production of vdWHs with atomic scale precision is crucial prerequisite for practical utilization. Here we present a generalized approach of random solution phase, high yield heteroassembly of semiconducting vdWHs by exploiting inherent surface charge states of 2D materials as well as chemical affinity of specific ligand end-functionalities. Facile removal of noncovalent functionalized ligands via simple pH reversal enables clean interfaces within vdWHs, yielding outstanding optoelectrical and electrochemical properties driven by fluent interfacial charge transfer among the layered 2D structures. The generality of this procedure is demonstrated by the formation of a series of different vdWHs such as WSe2-MoS2, graphene–MoS2 - and phospherene–WSe2 heterostructures. Atomically thin WSe2–MoS2 phototransistor displayed an exceptionally fast response time with high sensitivity. Graphene–MoS2 overcomes the inherent charge transfer issue of MoS2 for electrochemical catalyst. Phospherene–WSe2 successfully addresses poor ambient stability of phospherene together with enhanced surface activity towards chemical sensing.

Nonequilibrium Charge-Density-Wave Melting in 1T-TaS2 Triggered by Electronic Excitation: A Real-Time Time-Dependent Density Functional Theory Study.

Ultrafast charge transfer in van der Waals (vdW) heterostructures enables efficient control of two-dimensional material properties through strong optical absorption and subsequent carrier transfer. Here, using real-time time-dependent density functional theory coupled to molecular dynamics, we investigated the nonequilibrium dynamics of charge-density-wave (CDW) melting in 1T-TaS2 triggered by ultrafast charge transfer in 1T-TaS2/MoSe2 or WSe2 heterostructures. Despite the fast and sufficient charge transfer from the MoSe2 (or WSe2) "electrode" to the 1T-TaS2 layer, the electronic excitation of the vdW heterostructure does not lead to the nonthermal CDW transition of 1T-TaS2. Instead, the TaS2 lattice is heated by carrier-lattice scattering, leading to thermal CDW melting at high ionic temperatures. The lack of nonthermal melting follows from the fact that the time scale of carrier recombination in 1T-TaS2 is similar to or faster than that of charge transfer. These findings provide physical insights into understanding the CDW melting dynamics in vdW heterostructures under nonequilibrium conditions.

Dynamic control of moiré potential in twisted WS2—WSe2 heterostructures

Dynamic control of moiré potential in twisted WS2—WSe2 heterostructures

Optoelectronic properties and interfacial interactions of two-dimensional Cs2PbX4-MSe2 (M = Mo, W) heterostructures.

Constructing 2D inorganic perovskites and TMDs heterostructures is an effective method to design stable and high-performance perovskites optoelectronic applications. Here, we investigate the optoelectronic properties and interfacial interactions of Cs2PbX4–MSe2 (X = Cl, Br, I; M = Mo, W) heterostructures using first-principles calculations. Firstly, six Cs2PbX4–MSe2 interfaces remain stable in energy. With the halogen varying from Cl to I, the interlayer distances of Cs2PbX4–MSe2 heterostructures increase rapidly. The CBM and VBM of monolayer Cs2PbX4 are all higher than that of monolayer MSe2 and the charges transfer from Cs2PbX4 interfaces to MSe2 interfaces when they contact. Both Cs2PbX4–MSe2 heterostructures are type-II heterostructures, which can drive the photogenerated electrons and holes to move in opposite directions. What's more, Cs2PbCl4–MoSe2 heterostructures exhibit the highest charge transport efficiency among Cs2PbX4–MoSe2 heterostructures because Cs2PbCl4–MoSe2 heterostructures have the lowest exciton binding energies among Cs2PbX4–MSe2 heterostructures. In addition, the optical absorptions of all heterostructures are significantly higher than the corresponding Cs2PbX4 monolayers and MSe2 monolayers. The construction of Cs2PbX4–MoSe2 heterostructures is beneficial for improving the photoelectric performance of two-dimensional perovskite devices. Lastly, we found that the Cs2PbI4–WSe2 heterostructure has the largest PCE (18%) among Cs2PbX4–MSe2 heterostructures. The Cs2PbCl4–MoSe2 heterostructure exhibits great potential application in photodetector devices and the Cs2PbI4–WSe2 heterostructure has great potential application in solar cells.

Tailoring the band alignment and magnetic and optical properties of g-C3N4/WSe2 van der Waals heterostructures by vacancies and atomic doping

Tunable band structure and effective spatial separation of carriers are important for designing good optoelectronic devices. In this work, effects of interfacial defect including vacancies and [Formula: see text]- or [Formula: see text]-type doping on the band alignment and magnetic and optical properties of g-C3N4/WSe2 van der Waals heterostructures are systematically investigated under the premise of spin-orbit coupling density-functional theory. The results illustrate that the pristine g-C3N4/WSe2 heterostructure exhibits intrinsic type-I band alignment with a direct bandgap of 1.101 eV, and the absorption of UV-visible light can be effectively improved compared with that of isolated WSe2 and g-C3N4 monolayers. The N vacancies as well as [Formula: see text], [Formula: see text] and [Formula: see text] doping produce asymmetrical spin-up and spin-down states, bringing about the magnetization and even magnetic half-metallicity characteristics ([Formula: see text] and [Formula: see text] doping). The band edge positions of g-C3N4/WSe2 heterostructure can be also well adjusted by introducing vacancies and [Formula: see text]- or [Formula: see text]-type doping in the g-C3N4 layer, accompanied by the transition of band alignment from types I to II, which will remarkably promote the separation of photogenerated electron-hole pairs. The defective g-C3N4/WSe2 heterostructures can be considered as a promising candidate for spintronics and optoelectronic devices.

Epitaxial Single-Crystal Growth of Transition Metal Dichalcogenide Monolayers via the Atomic Sawtooth Au Surface.

Growth of 2D van der Waals layered single-crystal (SC) films is highly desired not only to manifest the intrinsic physical and chemical properties of materials, but also to enable the development of unprecedented devices for industrial applications. While wafer-scale SC hexagonal boron nitride film has been successfully grown, an ideal growth platform for diatomic transition metal dichalcogenide (TMdC) films has not been established to date. Here, the SC growth of TMdC monolayers on a centimeter scale via the atomic sawtooth gold surface as a universal growth template is reported. The atomic tooth-gullet surface is constructed by the one-step solidification of liquid gold, evidenced by transmission electron microscopy. The anisotropic adsorption energy of the TMdC cluster, confirmed by density-functional calculations, prevails at the periodic atomic-step edge to yield unidirectional epitaxial growth of triangular TMdC grains, eventually forming the SC film, regardless of the Miller indices. Growth using the atomic sawtooth gold surface as a universal growth template is demonstrated for several TMdC monolayer films, including WS2 , WSe2 , MoS2 , the MoSe2 /WSe2 heterostructure, and W1- x Mox S2 alloys. This strategy provides a general avenue for the SC growth of diatomic van der Waals heterostructures on a wafer scale, to further facilitate the applications of TMdCs in post-silicon technology.

Strong exciton-photon coupling in large area MoSe2 and WSe2 heterostructures fabricated from two-dimensional materials grown by chemical vapor deposition

Two-dimensional semiconducting transition metal dichalcogenides embedded in optical microcavities in the strong exciton-photon coupling regime may lead to promising applications in spin and valley addressable polaritonic logic gates and circuits. One significant obstacle for their realization is the inherent lack of scalability associated with the mechanical exfoliation commonly used for fabrication of two-dimensional materials and their heterostructures. Chemical vapor deposition offers an alternative scalable fabrication method for both monolayer semiconductors and other two-dimensional materials, such as hexagonal boron nitride. Observation of the strong light-matter coupling in chemical vapor grown transition metal dichalcogenides has been demonstrated so far in a handful of experiments with monolayer molybdenum disulfide and tungsten disulfide. Here we instead demonstrate the strong exciton-photon coupling in microcavities composed of large area transition metal dichalcogenide/hexagonal boron nitride heterostructures made from chemical vapor deposition grown molybdenum diselenide and tungsten diselenide encapsulated on one or both sides in continuous few-layer boron nitride films also grown by chemical vapor deposition. These transition metal dichalcogenide/hexagonal boron nitride heterostructures show high optical quality comparable with mechanically exfoliated samples, allowing operation in the strong coupling regime in a wide range of temperatures down to 4 Kelvin in tunable and monolithic microcavities, and demonstrating the possibility to successfully develop large area transition metal dichalcogenide based polariton devices.

Robust Interlayer Coupling in Two-Dimensional Perovskite/Monolayer Transition Metal Dichalcogenide Heterostructures.

Interlayer excitons have been extensively studied in monolayer transition metal dichalcogenide (TMD) heterobilayers mainly due to the long lifetime, which is beneficial for a wide range of optoelectronic applications. To date, the majority of investigations of interlayer excitons in TMD heterobilayers have been focusing on the geometric arrangement of structures, spin-valley lifetime, and interlayer valley excitons with interlayer hopping rules. Nevertheless, interlayer excitons in TMD heterobilayers strongly depend on the local atomic registry and coupling strength, which increase the complexity of the device fabrication. Here, we report pronounced interlayer exciton emission in two-dimensional (2D) perovskite/monolayer TMD heterostructures without the need of thermal annealing or specific geometric arrangements, and the interlayer exciton emission is rather general among 2D perovskites and monolayer TMDs. Such interlayer exciton emission completely dominates the emission spectrum at 78 K regardless of the stacking sequence, suggesting the robust interlayer coupling in 2D perovskite/monolayer TMD heterostructures. Furthermore, the interlayer exciton emission shows a large blue-shift with increasing laser intensity due to the repulsive dipole-dipole interaction and can persist above 220 K. Importantly, the interlayer exciton emission also possesses robust circular polarization in chiral 2D perovskite/monolayer WSe2 heterostructures, which can be applied to manipulate the valley degree of freedom for valleytronic devices. Our findings would provide a favorable platform to explore interlayer coupling and related physical processes in 2D perovskites and TMDs and further provoke more investigations into the understanding and controlling of excitonic effects and associated optoelectronic applications in van der Waals heterostructures over a broad-range spectral response.

Black phosphorus-based van der Waals heterostructures for mid-infrared light-emission applications

Mid-infrared (MIR) light-emitting devices play a key role in optical communications, thermal imaging, and material analysis applications. Two-dimensional (2D) materials offer a promising direction for next-generation MIR devices owing to their exotic optical properties, as well as the ultimate thickness limit. More importantly, van der Waals heterostructures—combining the best of various 2D materials at an artificial atomic level—provide many new possibilities for constructing MIR light-emitting devices of large tuneability and high integration. Here, we introduce a simple but novel van der Waals heterostructure for MIR light-emission applications built from thin-film BP and transition metal dichalcogenides (TMDCs), in which BP acts as an MIR light-emission layer. For BP–WSe2 heterostructures, an enhancement of ~200% in the photoluminescence intensities in the MIR region is observed, demonstrating highly efficient energy transfer in this heterostructure with type-I band alignment. For BP–MoS2 heterostructures, a room temperature MIR light-emitting diode (LED) is enabled through the formation of a vertical PN heterojunction at the interface. Our work reveals that the BP–TMDC heterostructure with efficient light emission in the MIR range, either optically or electrically activated, provides a promising platform for infrared light property studies and applications.