Ultra-high vacuum exfoliation method for the preparation of large-area single layer TMDC films

• Antonija Grubišić-Čabo (University of Groningen)

Date

Friday 25 October 2024

Time

11:15 - 12:45 hour

Address

Gorlaeus Building
Einsteinweg 55
2333 CC Leiden

Room

BM.1.23

Zhiying Dan, ¹ Ronak Sarmasti Emami,¹ Giovanna Feraco,¹ Melina Vavali,¹Dominic Ger-lach,¹Deepnarayan Biswas,² Tien-Lin Lee,² Petra Rudolf ¹and Antonija Grubišić-Čabo¹

¹ Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands.
² Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK.

Abstract

Two-dimensional transition metal dichalcogenides (2D TMDCs) have attracted significant attention as a potential platform for the next generation of electrical, optical and spintronic devices [1]. The prevalent method for preparing 2D materials, including 2D TMDCs, involves mechanical exfoliation using sticky tape [2]. This method produces 2D materials of highest quality, but they are usually small in size (tens of micrometers). In this context, we present our findings on the preparation of 2D WS2 and WSe2 using a recently developed kinetic in situ single-layer synthesis (KISS) method, which is performed in ultra-high vacuum and designed specifically for surface science research [3], Figure 1. The crystallinity and spatial morphology of 2D WS2 and WSe2 prepared on two distinct metallic substrates, Ag(111) and Au(111), using KISS method was investigated by X-ray photoelectron spectroscopy, low-energy electron diffrac-tion, atomic force microscopy and X-ray standing waves (XSW). In particular, we focus on the influence that different substrates and chalcogen atoms have on the size and quality of exfoliated 2D films. We find that the quality of the bulk TMDC crystal, in this case WS2 and WSe2, plays a key role in the success of the KISS method exfoliation. Additionally, preliminary XSW measurements indicate that the KISS synthe-sis method does not compromise or diminish the quality of the underlying substrate, emphasizing its po-tential as a non-destructive approach for 2D material synthesis.
 

Figure 1: A schematic illustrating the KISS exfoliation procedure

References

1. E. J. Sie, J. W. McIver, Y.-H. Lee, L. Fu, J. Kong, N. Gedik, Nat. Mater. 14, 290 (2015)
2. F. Liu, Prog. Surf. Sci. 96, 100626 (2021)
3. A. Grubišić-Čabo et al., Adv. Sci., 10, 2301243 (2023)