Investigation of the growth of few-layer SnS <sub>2</sub> thin films via atomic layer deposition on an O <sub>2</sub> plasma-treated substrate
Namgue Lee, Hyeongsu Choi, Hyunwoo Park, Yeonsik Choi, Hyunwoo Yuk, Jung-Hoon Lee, Hyeongtag Jeon
Abstract
Abstract Despite increasing interest in tin disulfide (SnS 2 ) as a two-dimensional (2D) material due to its promising electrical and optical properties, the surface treatment of silicon dioxide (SiO 2 ) substrates prior to the atomic layer deposition (ALD) deposition of SnS 2 has not been thoroughly studied. In this paper, we prepared two types of SiO 2 substrates with and without using an O 2 plasma surface treatment and compared the ALD growth behavior of SnS 2 on the SiO 2 substrates. The hydrophilic properties of the two SiO 2 substrates were investigated by x-ray photoelectron spectroscopy and contact angle measurements, which showed that using an O 2 plasma surface treatment tuned the surface to be more hydrophilic. ALD-grown SnS 2 thin films on the two different SiO 2 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 SnS 2 thin films, transmission electron microscopy was used. Our data revealed that using O 2 plasma surface treatment increased the growth rate of the initial ALD stage. Thus, the ALD-grown SnS 2 thin film on the SiO 2 substrate treated with O 2 plasma was thicker than the film grown on the non-treated SiO 2 substrate.