Wafer scale synthesis of organic semiconductor nanosheets for van der Waals heterojunction devices

Sirri Batuhan Kalkan,Andrey Turchanin,Fabian Alexander Christian Apfelbeck,Uwe Hübner,Bert Nickel,Ziyang Gan,Antony George,Emad Najafidehaghani

doi:10.1038/s41699-021-00270-9

Abstract

Organic semiconductors (OSC) are widely used for consumer electronic products owing to their attractive properties such as flexibility and low production cost. Atomically thin transition metal dichalcogenides (TMDs) are another class of emerging materials with superior electronic and optical properties. Integrating them into van der Waals (vdW) heterostructures provides an opportunity to harness the advantages of both material systems. However, building such heterojunctions by conventional physical vapor deposition (PVD) of OSCs is challenging, since the growth is disrupted due to limited diffusion of the molecules on the TMD surface. Here we report wafer-scale (3-inch) fabrication of transferable OSC nanosheets with thickness down to 15 nm, which enable the realization of heterojunction devices. By controlled dissolution of a poly(acrylic acid) film, on which the OSC films were grown by PVD, they can be released and transferred onto arbitrary substrates. OSC crystal quality and optical anisotropy are preserved during the transfer process. By transferring OSC nanosheets (p-type) onto prefabricated electrodes and TMD monolayers (n-type), we fabricate and characterize various electronic devices including unipolar, ambipolar and antiambipolar field-effect transistors. Such vdW p-n heterojunction devices open up a wide range of possible applications ranging from ultrafast photodetectors to conformal electronics.

Highlights

Heterojunctions based on organic semiconductors (OSCs) and monolayer transition metal dichalcogenides (ML TMDs), exploiting the advantages of both material systems, attract interest in the engineering of electronic, photonic and optoelectronic devices[1,2,3]
The polyacrylic acid (PAA) layer acts as the growth substrate for physical vapor deposition (PVD) of highly ordered pentacene or DNTT films with thicknesses ranging from 15 to 50 nm
We found out that a controlled release of the OSC films is possible by a water-assisted transfer technique, see Fig. 1

Summary

Introduction

Heterojunctions based on organic semiconductors (OSCs) and monolayer transition metal dichalcogenides (ML TMDs), exploiting the advantages of both material systems, attract interest in the engineering of electronic, photonic and optoelectronic devices[1,2,3].OSC exhibit excellent electronic properties which can outperform or act complementary to inorganic semiconductors[4,5,6]. The p-type OSC nanosheets were transferred onto prefabricated n-type MoS2 device structures to realize high-performance ambipolar and antiambipolar FETs. RESULTS AND DISCUSSION We found out that a controlled release of the OSC films is possible by a water-assisted transfer technique, see Fig. 1.

Results

Conclusion