Noninvasive Photodelamination of van der Waals Semiconductors for High-Performance Electronics

Abstract

Atomically thin two-dimensional (2D) van der Waals semiconductors are promising candidate materials for post-silicon electronics. However, it remains challenging to attain completely uniform monolayer semiconductor wafers free of over-grown islands. Here, we report the observation of the energy funneling effect and ambient photodelamination phenomenon in inhomogeneous few-layer WS${}_2$ flakes under low illumination fluencies down to several nW/$\mu$m${}^2$ and its potential as a non-invasive post-etching strategy for selectively stripping the local excessive overlying islands. Photoluminescent tracking on the photoetching traces reveals relatively fast etching rates around $0.3-0.8\mu$m/min at varied temperatures and an activation energy of $1.7$eV. By using crystallographic and electronic characterization, we also confirm the non-invasive nature of the low-power photodelamination and the highly preserved lattice quality in the as-etched monolayer products, featuring a comparable average density of atomic defects (ca.$4.2\times 10^{13}$cm${}^{-2}$) to pristine flakes and a high electron mobility up to $80$cm${}^2\cdot$V${}^{-1}\cdot$s${}^{-1}$) at room temperature. This approach opens a non-invasive photoetching route for thickness uniformity management in 2D van der Waals semiconductor wafers for electronic applications.

30 pages, 4 figures, with SI

References in corpus (8)

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Cited by in corpus (1)

• Oxidation kinetics and non-Marcusian charge transfer in dimensionally confined semiconductors