Van der Waals MoS₂/PdSe₂ Heterostructures Grown by Chemical Vapor Deposition for Broadband and Polarized Photodetection

Abstract

near-infrared (NIR) optical region and beyond. Then, in order to broaden the response spectrum range and improve the photoresponse of MoS 2 , van der Waals (vdWs) heterostructure-composed MoS 2 with another TMDC have been extensively and deeply investigated to make full use of not only the enhanced light absorption but also the interlayer interaction between the composed layers under light. [9][10][11][12][13] Lateral vertically stacked WS 2 /MoS 2 hybrid photodetectors with graphene as contact have achieved a photoresponsivity and photoconductive gain as high as 10 3 A W −1 and 3 × 10 4 , respectively. [14] The proposed WSe 2 /MoS 2 phototransistor has exhibited an excellent performance with specific detectivity of 5 × 10 11 Jones, high photoresponsivity of 2.7 × 10 3 A W −1 , and response time of 0.017 s. [15] Jung and co-workers reported an enhanced dye-sensitized solar cell with 8.07% conversion efficiency attained for MoS 2 /MoTe 2 counter electrode. [16] Besides those, multilayer ReSe 2 /MoS 2 p-n photodetectors showed a high photoresponsivity of 6.75 A W −1 and external quantum efficiency over 1200%. [17] It is also important to emphasize that these heterojunctions can make the photogenerated carriers separation more efficient by the aid of builtin electric field at the interface, which in turn improved the photodetection performance.Besides group-VI TMDCs, group-X TMDCs mainly including PtS 2 /Se 2 and PdS 2 /Se 2 have recently come under the spotlight as representative of stable TMDCs and attracted an increasing attention due to their superior properties, for example, wide spectrum range, good air stability, high carrier mobility, and strong interlayer interaction, and so on. [18][19][20][21][22] Group-X TMDCs are predicted to be promising semiconductors with narrow bandgap 0-0.25 eV in bulk and room-temperature carrier mobility higher than 1000 cm 2 V −1 s −1 by theoretical calculation. [23][24][25] Among them, PdSe 2 has emerged as a new 2D material for broadband spectrum photodetection with a strong thickness-dependent bandgap of 0-1.4 eV from bulk to monolayer. Specifically, it also possesses a pentagonal puckered structure which endows it strong in-plane anisotropic mechanical, optical, electrical, and thermal properties. [21,26] For photodetection, the PdSe 2 NIR photodetector shows a photoresponsivity of 660 A W −1 under 914 nm laser and the electrical property after 6 months keeping in the air show little change as published by Recently, group-X transition metal dichalcogenides with tunable distinct optical and superior electrical properties have displayed profound potential in various optoelectronic devices. In this work, novel van der Waals (vdWs) heterostructures composed of monolayer MoS 2 and few-layer PdSe 2 grown by chemical vapor deposition are employed in photodetectors for broadband and polarized photodetection. Excitingly, optoelectronic measurements show that the MoS 2 /PdSe 2 photodetector is sensitive to near-infrared light with responsivity as high as 6.9 A W −1 , specific detectiv...

High-Gain MoS2/Ta2NiSe5 Heterojunction Photodetectors with Charge Transfer and Suppressing Dark Current

“…[15][16][17]46,47 Because of the low dark current of the heterojunction device (Figure S6a), the D* of the MoS 2 / Ta 2 NiSe 5 photodetector is up to the highest value of 3.1 × 10 13 Jones, which is comparable to that of the pure MoS 2 (∼3.9 × 10 12 Jones) and Ta 2 NiSe 5 devices (∼1.2 × 10 12 Jones). The D* of the heterostructure is superior to that reported in the MoS 2 /PdSe 2 photodetector (6.3 × 10 10 Jones), 49 MoS 2 / MoTe 2 photodetector (1.4 × 10 8 Jones), 48 and MoS 2 /GaSe photodetector (2.3 × 10 11 Jones). 50 As described in Figure 5c, the EQE displays a similar trend with the power density compared with R and D*.…”

“…An extremely high responsivity of 515.6 A W –1 is obtained at the incident power density of 17.5 mW cm –2 , which is higher than that of all Ta 2 NiSe 5 -based phototransistors. − ,, Because of the low dark current of the heterojunction device (Figure S6a), the D * of the MoS 2 /Ta 2 NiSe 5 photodetector is up to the highest value of 3.1 × 10 13 Jones, which is comparable to that of the pure MoS 2 (∼3.9 × 10 12 Jones) and Ta 2 NiSe 5 devices (∼1.2 × 10 12 Jones). The D * of the heterostructure is superior to that reported in the MoS 2 /PdSe 2 photodetector (6.3 × 10 10 Jones), MoS 2 /MoTe 2 photodetector (1.4 × 10 8 Jones), and MoS 2 /GaSe photodetector (2.3 × 10 11 Jones) …”

The electronic and interfacial properties of a vdW heterostructure composed of penta-PdSe2and biphenylene monolayers

“…For example, a high electron fieldeffect mobility of B158 cm 2 V À1 s À1 in few-layer PdSe 2 extends its credibility in field-effect transistors (FETs). 27 From the device's perspective, a large rectification ratio of up to 6.3 Â 10 5 for PdSe 2 /MoTe 2 , 30 5.5 Â 10 5 for PdSe 2 /GeSe, 31 a high photoresponsivity of 58.8 A W À1 (at 1650 nm) for PdSe 2 /InSe, 32 6.9 A W À1 for PdSe 2 /MoS 2 , 33 39 synthesized an ultra-flat metallic carbon sheet, namely the biphenylene network (BPN), which is composed of tetra-, hexa-, and octa-gonal rings and features pure sp 2hybridization. By using first-principles calculations, some theoretical studies have also confirmed metallicity, 40 magnetic and topological ordering, 41 anisotropic charge transport, 42 and remarkable negative thermal expansion 43 in the BPN monolayer, which extend the functionality of this sheet for advanced nanodevices.…”

Ultrafast and Polarization-Sensitive ReS2/ReSe2 Heterostructure Photodetectors with Ambipolar Photoresponse

“…The van der Waals (vdWs) atomic crystals, as an emerging class of materials that possesses special structural, mechanical, optical, electrical, and chemical properties, including, but not limited to, thickness-tunable band structure and optoelectronics, dangling-bond free surface, abundant excitonic and valley–spin phenomenon, and giant magnetoresistance, have come under the spotlight and attracted tremendously increasing research attention in recent years. − Among them, transition metal dichalcogenides (TMDCs) are a typical series of layered vdWs material with the formula MX 2 , displaying great application potential in the fields of optoelectronics and electronics, such as field effect transistors, , photodetectors, − photocatalysis, and light-emitting diodes. , In addition to the freedom from atomic lattice matching requirements, two-dimensional vdW materials often permit vertical stacking without dangling bonds. Then, the implementation of vdW heterostructures not only promotes the discovery of novel phenomena, e.g., magic-angle superconductivity, twist-angle topological excitons, and interlayer magnetism, but also facilitates the construction and exploration of new devices. − An enhanced self-powered photodetector using WSe 2 /graphene/h-BN/MoS 2 heterostructure is demonstrated with an on/off ratio of about 1.2 × 10 5 and the highest photoresponsivity of 3.6 A/W ever reported for self-powered photodetectors . In graphene/hBN/graphene heterostructures, deep-ultraviolet electroluminescence and photocurrent generation is fulfilled at room temperature owing to the tunneling carrier injection from graphene to hBN .…”