Epitaxial Growth of Molecular Crystals on van der Waals Substrates for High-Performance Organic Electronics.

摘要

The growth of high-quality organic semiconductors on supporting substrates with minimal disorder is the key requirement for realizing high-performance organic electronics. However, the absence of an epitaxial relation and the presence of disorder make it particularly challenging to grow high-quality organic crystals having few defects and grain boundaries on conventional insulating substrates. Here, we report epitaxial growth of highly ordered, crystalline organic films on van der Waals (vdW) substrates and demonstrate high carrier mobility comparable to those of single-crystal counterparts. High quality rubrene films with large single-crystalline domains were grown on hexagonal boron nitride (h-BN) layers with an in-plane crystallographic registry. Furthermore, using graphene as the vdW electrical contacts, high field-effect mobility (11.5 sq cm V(exp 1) s(exp 1)) was achieved, attributable to an atomically sharp interface with low charge trap density between rubrene and h-BN. The ability to grow high-quality organic/inorganic epitaxial vdW heterostructures, combined with recent progress on large-area growth of layered materials, provides new opportunities for the scalable fabrication of high-performance organic electronic devices. Controlling the interface between organic films and inorganic substrates is of crucial importance for organic electronic applications, because this interface governs the initial nucleation during the growth of molecular films as well as the field-induced charge-carrier transport. In particular, charge transport is affected greatly by interfacial disorder, such as surface roughness and charge traps, as well as structural disorder of the molecular materials at the interface.