Large-Scale Synthesis of a Uniform Film of Bilayer MoS₂ on Graphene for 2D Heterostructure Phototransistors

Abstract

The large-scale synthesis of atomically thin, layered MoS2/graphene heterostructures is of great interest in optoelectronic devices because of their unique properties. Herein, we present a scalable synthesis method to prepare centimeter-scale, continuous, and uniform films of bilayer MoS2 using low-pressure chemical vapor deposition. This growth process was utilized to assemble a heterostructure by growing large-scale uniform films of bilayer MoS2 on graphene (G-MoS2/graphene). Atomic force microscopy, Raman spectra, and transmission electron microscopy characterization demonstrated that the large-scale bilayer MoS2 film on graphene exhibited good thickness uniformity and a polycrystalline nature. A centimeter-scale phototransistor prepared using the G-MoS2/graphene heterostructure exhibited a high responsivity of 32 mA/W with good cycling stability; this value is 1 order of magnitude higher than that of transferred MoS2 on graphene (2.5 mA/W). This feature results from efficient charge transfer at the interface enabled by intimate contact between the grown bilayer MoS2 (G-MoS2) and graphene. The ability to integrate multilayer materials into atomically thin heterostructures paves the way for fabricating multifunctional devices by controlling their layer structure.

Growth of Transition Metal Dichalcogenides and Directly Modulating Their Properties by Chemical Vapor Deposition

“…Except for combination between TMDs, separately grow TMDs and other layered materials is effective to form heterostructures. MoS2 can be grown on CVD grown h-BN film [107] or graphene [108][109][110][111][112][113] to form vertical heterostructures. Large area heterostructure film is promising in mass scale integration applications including FET arrays, Hall bar arrays, inverters, tunneling devices, etc.…”

Selective and confined growth of transition metal dichalcogenides on transferred graphene

“…The atomically sharp interfaces in these so-called van der Waals solids give rise to unique properties that depend on the characteristics of their constituent layers. 1 Graphene and transition metal dichalcogenides (TMDCs) are the most thoroughly investigated 2D materials to date, and heterostructures based on these materials have yielded numerous potential applications including photodetectors, 2,3 photoresponsive memory devices, 4 eldeffect transistors, 5,6 and quantum-well light-emitting diodes. 7 Many of these devices are based on vertically stacked 2D heterostructures, which are typically fabricated in one of three ways.…”

“…4,6,8 A second method is TMDC synthesis atop epitaxial graphene grown on a SiC substrate, [9][10][11][12][13] and a third is TMDC synthesis on graphene that has been transferred onto a silicon or quartz substrate. 2,3,5 One challenge common to all these methods is how to dene the locations of these 2D heterostructures prior to growth. This hurdle must be overcome before fabrication techniques can be scaled beyond single elements.…”

Integrating Graphene/MoS2 Heterostructure with SiNx Waveguide for Visible Light Detection at 532 nm Wavelength

“…The combination of graphene and MoS 2 is an attractive solution which can take advantages of the high mobility of graphene and the high photosensitivity of MoS 2 . Plenty vertical‐incidence photodetectors based on graphene, MoS 2 , and their combined heterostructure with high responsivity, fast photoresponse, and potential of large‐scale fabrication have been demonstrated, making it a promising candidate for high‐performance photodetection in the future. Note that the device performances vary dramatically owing to different 2D sheet preparation techniques (exfoliated or CVD‐grown) and stacking techniques (transferred or CVD‐grown), which have crucial impacts on 2D film qualities.…”