Vertical Heterostructures of Layered Metal Chalcogenides by van der Waals Epitaxy

Abstract

We report a facile chemical vapor deposition (CVD) growth of vertical heterostructures of layered metal dichalcogenides (MX2) enabled by van der Waals epitaxy. Few layers of MoS2, WS2, and WSe2 were grown uniformly onto microplates of SnS2 under mild CVD reaction conditions (<500 °C) and the heteroepitaxy between them was confirmed using cross-sectional transmission electron microscopy (TEM) and unequivocally characterized by resolving the large-area Moiré patterns that appeared on the basal planes of microplates in conventional TEM (nonsectioned). Additional photoluminescence peaks were observed in heterostructures of MoS2-SnS2, which can be understood with electronic structure calculations to likely result from electronic coupling and charge separation between MoS2 and SnS2 layers. This work opens up the exploration of large-area heterostructures of diverse MX2 nanomaterials as the material platform for electronic structure engineering of atomically thin two-dimensional (2D) semiconducting heterostructures and device applications.

Booming Development of Group IV–VI Semiconductors: Fresh Blood of 2D Family

“…c) Calculated total and projected density of state for the 5‐L MoS 2 /SnS 2 heterostructure, and charge density for several states of the 1‐L MoS 2 /SnS 2 heterostructure: the valence band edge (VBE) top, a representative state within peak (a) (middle), and a mixed‐character state within peak (c), lying approximately 1.8 eV above the Fermi level (bottom). (b,c) Reproduced with permission 245. 2014, American Chemical Society.…”

“…Especially, the dangling bonds on the interface of the heterostructures by mechanical transfer procedure may adsorb other molecules such as oxygen or water, resulting in passivation which is harmful for advanced electronic devices. Therefore, there are many attempts on the epitaxial growth of heterostructures 245, 246. Jin and co‐workers245 have achieved heteroepitaxial growth of thin layers of MoS 2 , WS 2 , and WSe 2 on SnS 2 microplates via a CVD procedure employing metal chlorides and sulfide or selenium powders at low temperature (<500 °C).…”

“…Therefore, there are many attempts on the epitaxial growth of heterostructures 245, 246. Jin and co‐workers245 have achieved heteroepitaxial growth of thin layers of MoS 2 , WS 2 , and WSe 2 on SnS 2 microplates via a CVD procedure employing metal chlorides and sulfide or selenium powders at low temperature (<500 °C). Taking MoS 2 /SnS 2 heterostructure, for example, typical PL spectra of a SnS 2 microplate and MoS 2 /SnS 2 microplate were demonstrated in Figure 7b.…”

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

“…Then MoX2 can be epitaxial growth on SnS2 ( Figure 11). [100] However, the growth temperature of the second material should be carefully controlled to maintain good quality of SnS2 and the grown material. [100] Furthermore, Jin et al have grown MoS2 on SnS2, TaS2, and graphene with layer controllability.…”

“…[100] However, the growth temperature of the second material should be carefully controlled to maintain good quality of SnS2 and the grown material. [100] Furthermore, Jin et al have grown MoS2 on SnS2, TaS2, and graphene with layer controllability. [101] The use of metal halide precursors at lower temperatures is more efficient for heterostructure growth, consistent with their previous work.…”