A new strategy to improve the performance of MoS2-based 2D photodetector by synergism of colloidal CuInS2 quantum dots and surface plasma resonance of noble metal nanoparticles

WS2/WSe2 Nanodot Composite Photodetectors for Fast and Sensitive Light Detection

“…68 The CVD-grown high-quality WSe 2 nanocrystals provide massive electrons to the WS 2 channel through the WS 2 /WSe 2 heterojunction with suppressed trap states compared to QDs, obtaining improved responsivity without sacrificing the response time. 27,44,62 To highlight the improvement achieved by the WS 2 /WSe 2 nanodot heterostructure, we compare our work with previously reported photodetectors based on the 0D-2D hybrid structure summarized in Table 1. Finally, we also explore the timeresolved photoresponse at different V gs 's and optical irradiances shown in Figure 5c,d, respectively.…”

“…25,26 Yet, some QDs/TMD hybrid photodetectors suffer from degraded operating speed, depending on the trap states introduced by QDs. 27,28 It is known that the excitonic behaviors of the 0D-2D heterostructure are affected by the size, density, and quality of the QDs, which determine the performance of the photodetector. 29,30 Although the large-area QDs can be synthesized by the sonication method, intercalation reaction, and hydrothermal method, 31,32 the toxicity, stability, and timeconsuming process of the QDs limit its application for optical devices.…”

“…The response time remains fast in a timescale of a few milliseconds due to the high crystallinity of WSe 2 nanodots with suppressed trap states, compared with other QDs/TMD photodetectors. 27,44 ■ EXPERIMENTAL SECTION Growth of 2D Materials. The pristine monolayer graphene was grown on a polycrystalline copper (Cu) foil with a thickness of 25 μm using an atmospheric pressure chemical vapor deposition (CVD) system.…”

“…The QDs function as a photosensitizer, which transfers massive photoexcited electrons to the channel and simultaneously photogates the underlying channel by means of the trapped photoexcited holes. MoS 2 photodetectors thus made have shown responsivity as high as 10 6 A/W. , Yet, some QDs/TMD hybrid photodetectors suffer from degraded operating speed, depending on the trap states introduced by QDs. , It is known that the excitonic behaviors of the 0D-2D heterostructure are affected by the size, density, and quality of the QDs, which determine the performance of the photodetector. , Although the large-area QDs can be synthesized by the sonication method, intercalation reaction, and hydrothermal method, , the toxicity, stability, and time-consuming process of the QDs limit its application for optical devices. , In addition, the increased dark current, owing to the leakage path induced by QDs, detriments the detectivity of the photodetector. Even this issue can be solved by the isolation process, surface damages might be induced during the patterning procedure. , Thus, chemical vapor deposition (CVD) seems to be the proper way to synthesize large-scale QDs with controllable size and density, which is suitable for integration with high yields. , A graphene-Bi 2 Te 3 heterostructure photodetector with Bi 2 Te 3 nanocrystals directly grown on monolayer graphene has been reported, which exhibits an enhanced photoconductive gain .…”

“…Using this device architecture, the improved responsivity is obtained compared to the WS 2 /WSe 2 puddle photodetector, owing to the dense WSe 2 nanocrystals with alleviated scattering. The response time remains fast in a timescale of a few milliseconds due to the high crystallinity of WSe 2 nanodots with suppressed trap states, compared with other QDs/TMD photodetectors. , …”