Growth of Complex 2D Material-Based Structures with Naturally Formed Contacts

Abstract

The difficulty of processing two-dimensional (2D) transition metal dichalcogenide (TMD) materials into working devices with any scalability is one of the largest impediments to capitalizing on their industrial promise. Here, we describe a versatile, simple, and scalable technique to directly grow self-contacted thin-film materials over a range of TMDs (MoS 2 , MoSe 2 , WS 2 , and WSe 2 ), where predeposited bulk metallic contacts serve as the nucleation site for the TMD material to grow, forming naturally contacted device structures in a single step. The conditions for growth as well as optical and physical properties are reported. Because the material grows controllably around the lithographically defined patterns, wafer scale circuits and complex device geometries can be envisioned, including lateral heterostructures of different TMD materials.

Thermal Annealing Effects on Naturally Contacted Monolayer MoS2

“…[30] This technique has been used to produce as-grown device structures and complex material geometries. [32,33] At typical growth temperatures, around 750 C, the MoS 2 forms a continuously connected film around the bulk transition metal pattern and no random, unconnected, MoS 2 growth is observed. At higher growth temperatures, around 850 C, the MoS 2 more easily migrates away from the patterns and may form isolated, free, regions of material, as shown in Figure 1d.…”

Toward automated classification of monolayer versus few-layer nanomaterials using texture analysis and neural networks

“…The growth time, which was typically between 10 to 15 min, was measured when the sulfur started to melt. At the end of growth time, the furnace was turned off and allowed to cool naturally back to room temperature, the above procedures of TMD growth were previously investigated by Aleithan (2018) 37,38 .…”

Lateral heterostructures and one-dimensional interfaces in 2D transition metal dichalcogenides

“…Also, a new scalable 2-step CVD method for lateral growth has been developed, allowing the fabrication of heteroribbons [34,70] with long interfaces in a non-triangular structure. Most recently, WSe 2 -MoS 2 [78] and WS 2 -MoS 2 HSs [86] are grown starting from both distinct metallic samples. This 2-step process promotes growth from distinct patterned metal contacts in a position-selective manner, as the interface is created at the meeting point between both flakes, as shown in figure 1(d).…”