Effect of plasma-cracked sulfur on the growth of tin-sulfide thin films by molecular beam deposition

Abstract In this study, we have investigated the growth behavior of SnS x thin films by molecular beam deposition using a plasma-cracked sulfur source to explore the influence of sulfur chemical activity on phase formation and stability. Plasma activation of elemental sulfur enabled the successful formation of stoichiometric and crystalline SnS at moderate substrate temperatures, while uncracked S₈ resulted in sulfur-deficient films. Furthermore, under higher sulfur flux and lower thermal budget, crystalline SnS 2 formation was observed. The phase selectivity was systematically evaluated through Raman spectroscopy, X-ray diffraction, and Auger electron spectroscopy, and the desorption behavior of SnS correlated well with reported vapor pressure data. These findings demonstrate that plasma cracking enhances sulfur reactivity and enables access to distinct tin sulfide phases depending on growth conditions. These results and discussions provide a basis for understanding SnS x thin-film growth and points toward future development of phase-selective IV–VI chalcogenide thin-film growth technique.