title: Towards a uniform and large-scale deposition of MoS2 nanosheets via sulfurization of ultra-thin Mo-based solid films.
abstract: Large-scale integration of MoS2 in electronic devices requires the development of reliable and cost-effective deposition processes, leading to uniform MoS2 layers on a wafer scale. Here we report on the detailed study of the heterogeneous vapor-solid reaction between a pre-deposited molybdenum solid film and sulfur vapor, thus resulting in a controlled growth of MoS2 films onto SiO2/Si substrates with a tunable thickness and cm(2)-scale uniformity. Based on Raman spectroscopy and photoluminescence, we show that the degree of crystallinity in the MoS2 layers is dictated by the deposition temperature and thickness. In particular, the MoS2 structural disorder observed at low temperature (<750 °C) and low thickness (two layers) evolves to a more ordered crystalline structure at high temperature (1000 °C) and high thickness (four layers). From an atomic force microscopy investigation prior to and after sulfurization, this parametrical dependence is associated with the inherent granularity of the MoS2 nanosheet that is inherited by the pristine morphology of the pre-deposited Mo film. This work paves the way to a closer control of the synthesis of wafer-scale and atomically thin MoS2, potentially extendable to other transition metal dichalcogenides and hence targeting massive and high-volume production for electronic device manufacturing.
authors.affiliation: Laboratorio MDM, IMM-CNR, Via C. Olivetti 2, I-20864 Agrate Brianza (MB), Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Vangelista
authors.forename: Eugenio
authors.initials: E
authors.lastname: Cinquanta
authors.forename: Christian
authors.initials: C
authors.lastname: Martella
authors.forename: Mario
authors.initials: M
authors.lastname: Alia
authors.forename: Massimo
authors.initials: M
authors.lastname: Longo
authors.forename: Alessio
authors.initials: A
authors.lastname: Lamperti
authors.forename: Roberto
authors.initials: R
authors.lastname: Mantovan
authors.forename: Francesco Basso
authors.initials: FB
authors.lastname: Basset
authors.forename: Fabio
authors.initials: F
authors.lastname: Pezzoli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Molle