Laser-enabled localized synthesis of Mo1-xWxS2 alloys with tunable composition

Alloying can tailor the optoelectronic properties of two-dimensional transition metal dichalcogenides (2D-TMDC) by bandgap tuning and shallowing of the deep-level defects, leading to enhancement in their photodetection performance. Hence, seeking for a scalable composition-controlled alloy preparation technology is essential. Here, direct laser-synthesis of micro-patterned Mo1-xWxS2 alloys is demon-strated. By irradiating composite single source precursor films of molybdenum and tungsten sulfides with a laser beam at visible wavelengths, photo-thermal decomposition takes place, thus forming high -quality Mo1-xWxS2 alloys in ambient conditions without any need for high-vacuum based environment. The Mo1-xWxS2 alloys composition is simply regulated by adjusting the volume ratio of the partial single source precursor solutions, in the final mixture solution. The stoichiometry, the structural, morphological and optical characteristics of laser-written alloys with different compositions have been investigated. Analysis of high-angle annular dark -field scanning transmission electron microscopy (HAADF-STEM) revealed the formation of the long-range (similar to 30 nm), few-layered crystals with randomly distributed molybdenum and tungsten metal atoms with no evi-dence of clustering. A photosensing device has been fabricated from laser-written Mo0.5W0.5S2 alloys to demonstrate the functionality of the material. (c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

By alloying, the optoelectronic properties of 2D-TMDC can be tailored, leading to enhanced photodetection performance. Seeking a scalable composition-controlled alloy preparation technology is essential.