Heterostructures based on inorganic and organic van der Waals systems

Abstract

The two-dimensional limit of layered materials has recently been realized through the use of van der Waals (vdW) heterostructures composed of weakly interacting layers. In this paper, we describe two different classes of vdW heterostructures: inorganic vdW heterostructures prepared by co-lamination and restacking; and organic-inorganic hetero-epitaxy created by physical vapor deposition of organic molecule crystals on an inorganic vdW substrate. Both types of heterostructures exhibit atomically clean vdW interfaces. Employing such vdW heterostructures, we have demonstrated various novel devices, including graphene/hexagonal boron nitride (hBN) and MoS2 heterostructures for memory devices; graphene/MoS2/WSe2/graphene vertical p-n junctions for photovoltaic devices, and organic crystals on hBN with graphene electrodes for high-performance transistors.

Epitaxy of highly ordered organic semiconductor crystallite networks supported by hexagonal boron nitride

“…Recently, two-dimensional (2D) van der Waals (vdW) materials6 have been proposed as substrates for the epitaxy of organic molecules5789101112. Their key advantage lies in the fact that these interfaces have vdW nature13, meaning that surfaces on which OSCs grow are atomically smooth with no dangling bonds and trapped charges at the interface.…”

“…Heterointerfaces with vdW gap between OSCs and 2D materials have been first utilized employing graphene as a carrier injection layer between OSCs and metallic contacts7, and as vdW electrodes14. Besides graphene, layered semiconductors such as transition metal dichalcogenides have been used to form vdW heterostructures with OSCs915, even realizing atomically thin vdW p-n junctions11.…”

Two-Dimensional Semiconductor Optoelectronics Based on van der Waals Heterostructures

“…The availability of 2D materials with various compositions and electronic structures enables one to stack these layers with atomic precision and to produce artificial van der Waals (vdW) heterostructures that are essentially different from conventional material heterostructures as further discussed in the Section 3 [50,51,52,53]. Such ability offers an exciting opportunity in new materials design for fundamental studies and device applications [7,8,9,10].…”

Strain engineering in semiconducting two-dimensional crystals

“…Transition metal dichalcogenides (TMDs) have been synthesized by vapour transport method [63,64], chemical vapour deposition [65][66][67][68] or van der Waals epitaxy [69][70][71]. High-quality molybdenum and tungsten dichalcogenides can be directly grown on insulating substrates with large single-crystal domains of 10 to 10000 µm 2 [64,65,68].…”