Ultra-thin WS2 growth by ALD from bis(tert-butylimido)bis(dimethylamido)tungsten and 1,2-ethanedithiol and detailed surface mechanism
Year: 2026
Type: preprint
Abstract: A molecular layer deposition/atomic layer deposition (MLD/ALD) strategy using bis(tert-butylimido)bis(dimethylamido)tungsten (BTBMW) and 1,2-ethanedithiol (EDT), the latter serving as a safer organic alternative to H2S, leads to the formation of ultrathin WS2 films via a molecular/hybrid tungsten organothiolate intermediate. A multiscale approach, involving Si/SiO2 wafers, silica nanobeads, and molecular models, provides mechanistic insight into the early stages of growth. It reveals a complex surface chemistry involving ligand exchange, partial reduction of tungsten, and degrafting processes with regeneration of Si-OH groups. Despite this complexity, the process evolves toward a self-limiting and reproducible growth regime. Annealing studies on Si/SiO2 wafers and silica nanobeads allow tracking the transformation of the organothiolate intermediate into crystalline WS2 and confirm that WS2 formation proceeds through a progressive and controlled conversion of the deposited phase into lamellar WS2 domains. The mechanistic study also suggests that the degrafting-induced mobility of thiolate species during deposition may contribute to the lateral growth observed during annealing.
Source: ChemRxiv
Institutions: Lyon 1 Université, Centre National de la Recherche Scientifique, Institut de Recherches sur la Catalyse et l'Environnement de Lyon, Catalyse, Polymérisation, Procédés et Matériaux, École d'Ingénieurs en Chimie et Sciences du Numérique, École Centrale de Lyon, Université de Lyon, Laboratoire de Tribologie et Dynamique des Systèmes, Matériaux Ingénierie et Science, Institut National des Sciences Appliquées de Lyon, École Normale Supérieure de Lyon
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213986499