Probing the chemical and electronic properties of the core-shell architecture of transition metal trisulfide nanoribbons

Ultraviolet and X-ray photoelectron spectroscopies are used to probe the chemical and electronic structure of an amorphous, 2-20 nm-thick shell that encases the crystalline core in core-shell nanoribbons of TaS ₃. The shell is chemically heterogeneous, containing elemental sulfur and a with a notable (S ₂) ^2- deficiency over the crystalline TaS ₃ core. We find nanoribbon stability to be substrate-dependent; whilst the ribbons are stable on the native oxide of a silicon surface, mass transport of sulfur species between the amorphous shell and a gold substrate leads to a significant change in the electronic properties of the nanomaterials. Our observations may have general implications for the incorporation of nanostructured transition metal chalcogenides into electronic devices.