Intercalation and hybrid heterostructure integration of two-dimensional atomic crystals with functional organic semiconductor molecules

Abstract

Van der Waals (vdW) integration affords semiconductor heterostructures without constrains of lattice matching and opens up a new realm of functional devices by design. A particularly interesting approach is the electrochemical intercalation of two-dimensional (2D) atomic crystal and formation of superlattices, which can provide scalable production of novel vdW heterostructures. However, this approach has been limited to the use of organic cations with non-functional aliphatic chains, therefore failed to take the advantage of the vast potentials in molecular functionalities (electronic, photonic, magnetic, etc.). Here we report the integration of 2D crystal (MoS 2 , WS 2 , highly oriented pyrolytic graphite (HOPG), WSe 2 as model systems) with electrochemically inert organic molecules that possess semiconducting characteristics (including perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA), pentacene and fullerene), through on-chip electrochemical intercalation. An unprecedented long-range spatial feature of intercalation has been achieved, which allowed facile assembly of a vertical MoS 2-PTCDA-Si junction. The intercalated heterostructure shows significant modulation of the lateral transport, and leads to a molecular tunneling characteristic at the vertical direction. The general intercalation of charge neutral and functional molecules defines a versatile platform of inorganic/organic hybrid vdW heterostructures with significantly extended molecular functional building blocks, holding great promise in future design of nano/quantum devices.

Emerging field of few-layered intercalated 2D materials

“…85 Recently, He et al performed the electrochemical intercalation of the neutral organic semiconductor molecule perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) into few-layered MoS 2 demonstrating a powerful design scheme for the fabrication of well-dened organic devices. 95 This may bridge the gap from the research of 2DMs and vdW heterostructures and organic semiconductor research. Electrochemical intercalation of 2DMs enables a high control over the intercalation process by controlling the applied external bias.…”

Intercalation Strategy in 2D Materials for Electronics and Optoelectronics

“…He et al reported organic semiconductor (perylene‐3,4,9,10‐tetracarboxylic dianhydride, PTCDA) intercalation in MoS 2 by electrochemical methods. [ 160 ] The pristine MoS 2 exhibits the n‐type semiconductor behavior, but PTCDA‐MoS 2 shows metallic characteristics induced by the heavy electrons doping effect from the PTCDA intercalants ( Figure a). This degenerately n‐type doping method offers a new platform for further constructing functional heterojunctions.…”

“…a–c) Reproduced with permission. [ 160 ] Copyright 2020, Tsinghua University Press. d) Schematics of the spatially controlled intercalation process for SnS 2 .…”

An In Situ Spectral Monitoring Scheme for Advanced Manufacturing of Novel Nanodevices

“…Considering material structure for nanodevices, the hybrid systems consisting of 2D and organic semiconductor thin films have sparked new research directions [17][18][19][20][21], and the combination of the advantages of both 2D and organic materials [22][23][24] has been widely con-sidered to be promising for developing the novel nanodevices in the future. In recent years, the structures comprising van der Waals (vdW) epitaxial organic semiconductor films with controllable layers on the 2D material surface have emerged as one of the prime research highlights, as the properties and performance of the nanodevices based on such structures effectively correlate with the thickness of the organic layers [25][26][27][28]. Therefore, in order to satisfy the device functions and improve the production quality, a monitoring scheme, which is able to analyse the optical properties of thin films with different thicknesses, is essential for the advanced manufacturing of nano-and sub-nanodevices, especially the devices based on the structure of 2D/ organic thin films which have been mentioned above.…”