Novel and Enhanced Optoelectronic Performances of Multilayer MoS₂–WS₂ Heterostructure Transistors

Abstract

1wileyonlinelibrary.com gap around 1-3 eV and display advantageous optoelectronic properties. [ 9,10 ] For example, the fi eld-effect transistors based on monolayer or few-layer MoS 2 have been reported to exhibit an excellent on/ off ratio (∼10 8 ) and room-temperature mobility of >200 cm 2 /Vs, and the layered WS 2 has also been reported to exhibit 10 5 room temperature modulation and bipolar behavior. [ 11,12 ] For photodetection, the layered TMDs based photodetectors have been demonstrated with very high responsivity and fast photoresponse. [13][14][15] In parallel with the study of the single layer graphene-like materials, Van der Waals heterostructures and the corresponding devices fabricated by stacking different 2D crystals on top of each other have also been gaining much attention recently. These systems have revealed some novel properties and new phenomena that could trigger new revolution in architecture design of heterostructures for integrated optoelectronic applications. For example, the graphene heterostructures with 2D h-BN or MoS 2 layers acting as vertical transport barrier are fabricated and exhibit room-temperature switching ratio of 50 and 10 000, respectively. [ 16 ] Following the success, the vertical integration of multi-heterostructures of graphene and MoS 2 are reported for the fabrication of a new generation of vertical fi eld-effect transistors [ 17 ] (VFETs) with an on-off ratio >10 3 and a high current density of up to 5000 A/cm 2 . The vertically stacked heterostructures of graphene and MoS 2 are also demonstrated to display remarkable multiple optoelectronic functionality, including highly sensitive photodetection and gate-tunable persistent photoconductivity, [ 18 ] gate-tunable photocurrent generation with a maximum internal quantum effi ciency up to 85%, and huge capacity of information storage with a factor of 10 4 difference between memory states and erase states. [ 19,20 ] Moreover, the VFETs based on the graphene-WS 2 heterostructures are also fabricated with unprecedented current modulation exceeding 10 6 at room temperature. [ 21 ] These results suggest that the stacked multi-heterostructures of layered materials could open up new opportunities in future nanoelectronic devices with large-scale integration. Indeed, there are large number of 2D materials that can be exfoliated with micromechanical cleavage method and combined together to create various and tailored heterostructures. Novel and Enhanced Optoelectronic Performances of Multilayer MoS 2 -WS

Electronic and optical properties of novel carbon allotropes

“…That is, graphene opens an avenue to develop the 2D semiconducting materials for multifunctional optoelectronic device applications in the future, and many other 2D materials which exhibit a variety of extraordinary properties are being explored and designed [8][9][10][11][12] . Because of their atomic scale thickness, the existence of quantum confinements, and other unique planar advantages, 2D materials are attractive for use in low-power, smaller, more flexible, and more efficient next-generation nanoelectronic devices, as well as for catalysis, sensing, and energy storage applications [13][14][15][16][17][18] . The physical and chemical properties of 2D materials are intimately related to their atomic arrangement.…”

Optimal light harvesting in 2D semiconductor heterostructures

“…A thicker device made of ptype few-layer MoS 2 and p-type few-layer WS 2 has a rectifying and bipolar behavior and moreover can function not only as a photovoltaic cell but also as a self-driven photo-detector with photo-switching ratio exceeding 10 3 . This indicates strong light interaction in the device even though both few-layer TMDCs have indirect band gaps [13]. The performance of devices based on 2D heterostructures can also be improved by optimizing light absorption in the stack by coupling plasmonic nanoantennae or microcavities to the structures [14][15][16].…”

Progress on Crystal Growth of Two-Dimensional Semiconductors for Optoelectronic Applications

“…High-performance exfoliated and transfer-stacked heterojunctions like WS 2 /MoS 2 , WSe 2 /MoS 2 , WSe 2 /MoSe 2 , graphene/TMDC photodetectors have been extensively studied and reported with high EQE (up to 278%) and fast response (up to 100 GHz) [109,[142][143][144][145]. However, it should be noted that, although the optical and electrical properties of transferred heterojunctions are usually superior to those formed by CVD methods, polymer contamination can deteriorate interfacial quality during the transfer process.…”