Lamellar metal chalcogenides have come into the spotlight due to their semiconducting nature, which is distinct from the most studied 2D semi-metallic graphene. Over the past twenty years, researchers have focused on exploring the anisotropic physical properties of lamellar metal chalcogenides, unveiling new properties due to the thickness-dependent nature, which allows these materials to represent an ultimate level of miniaturization. The lack of scalable fabrication methods of continuous ultra-thin films on developed surfaces, at moderate temperatures, stems an obstacle for the deployment of these materials. In this context, the objective of this thesis was to obtain continuous ultra-thin film of lamellar metal sulfides on non-epitaxial substrates (thermal silicon oxide which is widely used in microelectronics) by performing a complete dissociation between growth and crystallization. For that purpose, we used an innovative two-step process approach comprising the growth of an amorphous thin film by Atomic Layer Deposition/Molecular Layer Deposition (ALD/MLD) and a subsequent thermal annealing for obtaining the crystallization. The replacement of the highly toxic H₂S co-reactant often used for growing ALD sulfide thin films with a safer organic molecule, i.e. 1,2 ethandithiol (EDT), permits to generate an amorphous inorganic/organic hybrid thin film at low temperature.

     The process was applied for the synthesis of Titanium Disulfide (TiS₂) ultrathin films. Amorphous thin films (Ti-thiolate) were obtained by ALD/MLD process at 50 °C then, converted into textured ultra-thin films of TiS₂ upon the annealing under Ar/H₂ gas. Thanks to the high brilliance of the synchrotron, the process was monitored by in situ X-ray techniques, which allows to evaluate the repetitive self-limiting behavior from the first ALD/MLD cycle during the growth of the amorphous Ti-thiolate, and to observe the local structure transition during the annealing step. In situ measurements coupled with ex situ characterizations (Raman, XPS, HAXPES, and TEM) evidenced the synthesis of ultra-thin film of 5.5 nm upon annealing at mild temperature (300 °C). Four-points and spectroscopic ellipsometry measurements confirmed a semi-conductor behavior with a direct band gap of 1.72 eV.

     Besides, promising preliminary results on the synthesis of Gallium Sulfide (GaS_x) thin films were obtained. During this work, an ALD/MLD window has been explored with EDT and a homogeneous film has been obtained at 250 °C. By contrast, we targeted to the synthesis of Tin Sulfide (SnS_x) with EDT. However, the growth was not successful. Nevertheless, mechanistic studies were performed on a high surface area substrate that contributed to explain the result.