Vertical heterostructures of MoS₂ and graphene nanoribbons grown by two-step chemical vapor deposition for high-gain photodetectors

Abstract

Heterostructures of two-dimensional (2D) layered materials have attracted growing interest due to their unique properties and possible applications in electronics, photonics, and energy. Reduction of the dimensionality from 2D to one-dimensional (1D), such as graphene nanoribbons (GNRs), is also interesting due to the electron confinement effect and unique edge effects. Here, we demonstrate a bottom-up approach to grow vertical heterostructures of MoS2 and GNRs by a two-step chemical vapor deposition (CVD) method. Single-layer GNRs were first grown by ambient pressure CVD on an epitaxial Cu(100) film, followed by the second CVD process to grow MoS2 over the GNRs. The MoS2 layer was found to grow preferentially on the GNR surface, while the coverage could be further tuned by adjusting the growth conditions. The MoS2/GNR nanostructures show clear photosensitivity to visible light with an optical response much higher than that of a 2D MoS2/graphene heterostructure. The ability to grow a novel 1D heterostructure of layered materials by a bottom-up CVD approach will open up a new avenue to expand the dimensionality of the material synthesis and applications.

Hydrogen on hybrid MoS2/graphene nanostructures

“…Despite the fact that LDA is used with caution in the case of atomic layers coupled with van der Waals (vdW) interactions, important conclusions have been drawn for hybrid MoS 2 /graphene systems using such methods. We tested other functionals to find that LDA gives the interlayer MoS 2 /graphene distance closest to experimental data and in agreement with other calculations . Our overall results are also consistent with recent DFT calculations that use more sophisticated functionals for the description of long range vdW interactions .…”

“…Quasi‐1D (nanoribbons) and 0D (nanoflakes) structures possess metallic edges . Electronic devices have already been developed and, furthermore, when combined with gapless graphene, TMDs open up exciting possibilities for applications in optoelectronics and catalysis . Recent fabrication of vertical TMD/graphene heterostructures may also prove to be important in the search for the optimal HER catalyst.…”

“…For the C 50 Mo 16 S 32 supercell, corresponding values are 0.49%, –1.36%, and 3.32 Å. In all hybrid nanostructures presented here, the distance between graphene C atoms and the closest S atoms is very close to 3.30 Å . Adhesion of nanoribbons and nanoflakes on graphene has a weak dependence on the orientation of the nanostructures.…”

Synthesis, structure and applications of graphene-based 2D heterostructures

“…At the same time, direct growth methods can provide much cleaner interfaces than those obtained in mechanical stacked samples, especially when two-step growth approaches are employed. Direct bottom-up growth methods have already been reported for the synthesis of h-BN on top of graphene 68,69 and of graphene on h-BN; [70][71][72][73][74][75][76][77][78][79][80][81][82][83][84] of several TMDs on graphene, including MoS 2 , 69,[85][86][87][88][89][90][91][92][93][94][95][96] WS 2 , [97][98][99][100] MoSe 2 , 101 WSe 2 , 69,90,102,103 105 and of other materials such as GaSe, 106,107 nontransition metal chalcogenides [108][109][110] , single layers of metal oxides such as ZnO, 111 or perovskites 112 on graphene. Most of those methods to synthesize heterostructures have evolved along with the ...…”

Synthesis of Composite Nanosheets of Graphene and Boron Nitride and Their Lubrication Application in Oil

“…Chemical vapor deposition (CVD), hydrothermal, and mechanical transfer methods can be used to produce various composite nanosheets on substrate surfaces at a small scale. However, synthesis of a large quantity of composite nanosheets is still a considerable challenge.…”