A critical role of hydrogen sulfide evolution during MOCVD of single phase thin film tin sulfide using ditertiarybutylsulfide as a less toxic precursor

Thin film tin sulphide (SnS) was deposited on to molybdenum (Mo) substrates using metal organic chemical vapor deposition at 470 o C using tetraethyltin and ditertiarybutylsulfide as precursors. In situ mass spectroscopy was used to study the exhaust gas species downstream of the reaction zone. The precursor vapor carrier gas was either nitrogen or hydrogen, thin film SnS only forming when the latter was used. Mass spectroscopy determined that hydrogen sulfide was being produced and playing a critical role in the vapor phase reaction process and adsorption of tin and sulfur on to the Mo surface. As-grown grain sizes were determined by scanning electron microscopy and were observed to be large averaging around 2 microns across. X-ray diffraction showed the films to be single phase SnS without any parasitic Sn 2 S 3 or SnS 2 phases, with a small amount of MoS 2 also being detected.