Growth Mechanism of Alternating Defect Domains in Hexagonal WS<sub>2</sub> via Inhomogeneous W‐Precursor Accumulation
Gwang Hwi An, Seok Joon Yun, Young Hee Lee, Hyun Seok Lee
Abstract
Abstract While a hexagonal WS 2 monolayer, grown by chemical vapor deposition, exhibits distinctive patterns in photoluminescence mapping, segmented with alternating S‐vacancy (SV) and W‐vacancy (WV) domains in a single crystal, the formation mechanism for native alternating defect domains remains unresolved to date. Here, the formation mechanism of alternating defect domains in hexagonal WS 2 via the precursor accumulation model is experimentally elucidated. A triangular WS 2 seed is initially formed, followed by a hexagonal flake. Alternating W‐rich (SV) and W‐deficient (WV) domains are constructed in hexagonal WS 2 flake, which is confirmed by confocal photoluminescence mapping and secondary ion mass spectroscopy. This is explained by the accumulation or scarcity of W‐precursors at the edge of the WS 2 flake. The W‐precursors accumulate near the edges of the initial triangular WS 2 seed over time, while they are deficient near the corners of the triangular WS 2 , eventually forming WV domains in the truncated hexagonal domains. The heterogeneous accumulation becomes more prominent in the presence of H 2 gas through desorption of the W‐precursors.