Pulsed laser deposition for the synthesis of monolayer WSe₂

Atomically thin films of WSe₂ from one monolayer up to 8 layers were deposited on an Al₂O₃ r-cut (⁠$11¯02$⁠) substrate using a hybrid-Pulsed Laser Deposition (PLD) system where a laser ablation of pure W is combined with a flux of Se. Specular X-ray reflectivities of films were analysed and were consistent with the expected thickness. Raman measurement and atomic force microscopy confirmed the formation of a WSe₂ monolayer and its spatial homogeneity over the substrate. Grazing-incidence X-ray diffraction uncovered an in-plane texture in which WSe₂ [$101¯0$] preferentially aligned with Al₂O₃ [$112¯0$]. These results present a potential to create 2D transition metal dichalcogenides by PLD, where the growth kinetics can be steered in contrast to common growth techniques like chemical vapor deposition and molecular beam epitaxy.