(Invited) Transferable Organic Semiconductor Nanosheets for Van Der Waals Heterojunction Devices

Abstract

The combination of organic semiconductors (OSCs) and two-dimensional materials provides a new basis to harness the advantages of both material systems, for example to fabricate unipolar pentacene thin-film transistors using graphene contacts [1] and p-n junctions using pentacene and molybdenum disulfide [2]. However, the fabrication of such devices by vapor deposition of OSCs is a challenge because growth is limited by the surface-dependent diffusion of small molecules. In this talk, I will present a novel method for the preparation of transferable OSC nanosheets that overcomes this problem. Highly crystalline, wafer-scale (3") nanosheets as thin as 20 nm can be obtained by precisely delaminating the OSC layer from a water-soluble sacrificial film in an appropriate wetting geometry. These free-floating films are then deposited on arbitrary substrates while maintaining morphology and crystallinity. Consequently, we demonstrate functional OSC nanosheets on top of prefabricated electrodes and monolayer MoS2, resulting in devices such as unipolar, ambipolar, and anti-ambipolar field effect transistors [3].