Capturing Reaction Kinetics of Atomically Thin Device Materials by High-throughput in-operando SEM

For the ever increasing family of layered 2D materials many exciting properties and device concepts have been reported, yet the understanding of fundamental mechanisms that can underpin scalable process technology for these materials is lagging far behind. We developed cross-correlative operando probing capability to “unblind” the underlying mechanisms, including open and closed cell approaches for XPS, optical spectroscopy, and scanning and transmission electron microscopy.[1-4]. While the previous focus has been to sample select process conditions, this talk will focus on our efforts to access and fast screen the entirety of the vast, interconnected parameter space. We adapted a SEM to allow operando reaction monitoring for the formation and etch reactions of atomically thin WS2 layers. This allows us to unlock a data-driven approach to understanding the underlying complex kinetics across scales. As a model system we focus on the thermal oxidation of WS2 monolayer crystals. Understanding material oxidation is fundamental to corrosion, heterogeneous material interfacing and integrated processing across a horizon of applications. We discuss statistical approaches and analysis of spatial and time dependent behaviour, connecting to previous literature and highlighting the many opportunities our approach can open.

[1] Weatherup et al., Nano Lett. 16, 6196 (2016)

[2] Wang et al., ACS Nano 13, 2114 (2019)

[3] Fan et al., Nanoscale 12, 22234 (2020)

[4] Schmitt et al., Nature 608, 499 (2022)