Non-Invasive Photodelamination of van der Waals Semiconductors for High-Performance Electronics.

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/μm 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 μm/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 (∼4.2×10 13 cm -2 ) to pristine flakes and a high electron mobility up to 80 cm 2 V -1 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. This article is protected by copyright. All rights reserved.