Synthesis and characterization of Mo and W compounds for disulfide materials

Abstract

MoS2 and WS2 are spotlighted as fungible materials of graphene that can be used in electronic devices owing to being semiconductors with indirect and direct band gaps. Precursors (Mo(NtBu)2(StBu)2 (1), W(NtBu)2(StBu)2 (2)) suitable for the deposition of these materials were synthesized and characterized. The molecular structures of 1 and 2 exhibit a tetrahedral geometry according to single‐crystal x‐ray crystallography. Thermogravimetric analyses of 1 and 2 showed two‐step weight loss. The residues from each step of 1 were MoS3 and MoS2, and these results were consistent with the subsequent deposition results of 1. We successfully established a PEALD‐MoS2 process using 1 and H2S plasma as the precursor and reactant, respectively, at relatively low temperatures of 150–300 °C without any post‐sulfurization process. A temperature‐dependent selective deposition of MoSx phases was observed with the growth of amorphous MoS3 films (150–200 °C), and crystalline MoS2 films (250–350 °C).