Organosulfur Precursor for Atomic Layer Deposition of High-Quality Metal Sulfide Films

Atomic layer deposition (ALD) of metal sulfides has aroused tremendous interest recently for its promising applications in many varieties of areas. However, most of the metal sulfide ALD processes have to use the highly toxic, explosive, and corrosive H₂S as the sulfur precursor, which leads to serious concerns for large-scale applications. To circumvent this issue, we herein report an organosulfur precursor of di-tert-butyl disulfide (TBDS) to replace H₂S for ALD of metal sulfides. The new ALD process using TBDS with an amidinate-type nickel precursor is demonstrated to show an ideal ALD growth behavior, and it can produce high-quality nickel sulfide (NiS_x) thin films with very good purity. An in situ mechanism investigation based on X-ray photoelectron spectroscopy and quartz crystal microbalance further unveils the crucial surface reaction of TBDS during the ALD. In addition, we demonstrate an important application of this new ALD method to synthesize a high-performance electrocatalyst.