Layered NbS₂ contacts formed via H₂S reaction with Nb for high-performance WSe₂-channel p-type transistors

Abstract Metallic transition metal dichalcogenides (TMDCs) are garnering attention as source/drain contact materials for TMDC-channel transistors. We demonstrate that NbS 2 , a metallic TMDC with a high effective work function of 4.69 eV, improves the performance of WSe 2 p-type transistors when utilized as a contact material at the source/drain. NbS 2 was synthesized through H 2 S annealing of Nb on WSe 2 . The annealing temperature was optimized to 600 °C, effectively balancing Nb sulfidation while minimizing damage to WSe 2 . The NbS 2 contacts formed through this process yielded an improvement in on-state current for WSe 2 p-type transistors, attributed to reduced contact resistance. Thus, NbS 2 emerges as a promising contact material.