MSE Graduate Seminar: Electrical Transport in Mixed-dimensional Semiconductor van der Waals Heterostructures

The isolation of graphene in 2004 inspired efforts to identify and isolate other 2D materials. Over the past decade, many of these materials have begun to see their integration into van de Waals (vdW) heterostructures, as any passivated surface free of dangling bonds will interact with another through vdW forces. However, since this isn’t limited to interplanar interactions, mixed-dimensional vdW heterostructures have begun to emerge in which 2D monolayers are combined with 0D, 1D and 3D structures.

1D/2D heterostructures in which both materials are semiconductors are of particular interest due to constrained carrier transport and weak screening effect in nanowires as well as strong quantization in 2D materials. In this seminar, results on such a 1D/2D vdW heterostructure are presented. Cadmium selenide (CdSe) nanowires were synthesized through vapour phase deposition, after which molybdenum diselenide (MoSe2) flakes were isolated through mechanical exfoliation. The electrical properties of both materials were investigated through the fabrication of field-effect transistors via lithographic techniques. Finally, in addition to creating the CdSe/MoSe2 heterostructure, a computational model was created to better understand the system.