Synthesis of SnS Thin Films by Atomic Layer Deposition at Low Temperatures

5 years ago

Synthesis of SnS Thin Films by Atomic Layer Deposition at Low Temperatures

Cheol Seong Hwang, Jeong Hwan Han, Jin-Sang Kim, Seong Keun Kim, Ji-Won Choi, Young Geun Song, Jung Joon Pyeon, Hae-Ryoung Kim, In-Hwan Baek, Chong-Yun Kang, Taek-Mo Chung, Seung-Hyub Baek

Two-dimensional (2-D) metal chalcogenides have received great attention because of their unique properties, which are different from bulk materials. A challenge in implementing 2-D metal chalcogenides in emerging devices is to prepare a well-crystallized layer over large areas at temperatures compatible with current fabrication processes. Tin monosulfide, a p-type layered semiconductor with a high hole mobility, is a promising candidate for realizing large-area growth at low temperatures because of its low melting point. However, tin sulfides exist in two notable crystalline phases, SnS and SnS₂. Therefore, it is imperative to control the oxidation state of Sn to achieve a pure SnS film. Here, the synthesis of SnS thin films by atomic-layer-deposition (ALD) is demonstrated using bis(1-dimethylamino-2-methyl-2-propoxy)tin(II) and H₂S as Sn and S sources, respectively, over a wide temperature window (90–240 °C). Impurities such as carbon, oxygen, and nitrogen were negligibly detected. The morphological evolution of plate-like orthorhombic SnS grains was observed above 210 °C. Moreover, properties of thin film transistors and gas sensors using SnS films as the active layers were investigated. The SnS ALD process would provide promising opportunities to exploit the intriguing properties of the 2-D metal chalcogenides for realizing emerging electronic devices.

Publisher URL: http://dx.doi.org/10.1021/acs.chemmater.7b01856

DOI: 10.1021/acs.chemmater.7b01856