Investigation of the growth of few-layer SnS2 thin films via atomic layer deposition on an O2 plasma-treated substrate.

Despite increasing interest in tin disulfide (SnS₂) as a two-dimensional (2D) material due to its promising electrical and optical properties, the surface treatment of silicon dioxide (SiO₂) substrates prior to the atomic layer deposition (ALD) deposition of SnS₂ has not been thoroughly studied. In this paper, we prepared two types of SiO₂ substrates with and without using an O₂ plasma surface treatment and compared the ALD growth behavior of SnS₂ on the SiO₂ substrates. The hydrophilic properties of the two SiO₂ substrates were investigated by x-ray photoelectron spectroscopy and contact angle measurements, which showed that using an O₂ plasma surface treatment tuned the surface to be more hydrophilic. ALD-grown SnS₂ thin films on the two different SiO₂ substrates were characterized by x-ray diffraction, Raman spectroscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. To estimate the exact thickness of the ALD-grown SnS₂ thin films, transmission electron microscopy was used. Our data revealed that using O₂ plasma surface treatment increased the growth rate of the initial ALD stage. Thus, the ALD-grown SnS₂ thin film on the SiO₂ substrate treated with O₂ plasma was thicker than the film grown on the non-treated SiO₂ substrate. [ABSTRACT FROM AUTHOR]