Effect of defects on ballistic transport in a bilayer SnS₂-based junction with Co intercalated electrodes

This study theoretically investigates the defect-related electronic structure and transport properties in a device where a semiconductor bilayer SnS₂ (BL-SnS₂) serves as the central scattering region and bilayer SnS₂ with cobalt atom intercalation (Co-SnS₂) as the metallic electrodes. The Co-SnS₂/BL-SnS₂ junction forms an ohmic contact, which is robust to defects. Low contact resistances of 52.1 Ω μm and 56.2 Ω μm are obtained in the zigzag (ZZ) and armchair (AC) transport directions, respectively. Defects, whether near the interface or in the middle of the central region, reduce the barrier between metal and semiconductor and the contact resistance. In particular, defects in the middle of the central region introduce impurity states and may result in resonant tunneling processes. This causes leakage current in the AC direction but not in the ZZ direction because impurity-associated transmission peaks in the latter are always outside the bias window.