Investigating Metal Dopants for Lowering the Contact Resistance of Top Gold Contacted Monolayer MoS2

Abstract: The interface properties between gold (Au) contacts and molybdenum disulfide (MoS2) are critical for optimizing the performance of semiconductor devices. This study investigates the impact of metal dopants (D) on the transport properties of MoS2 devices with top Au contacts, aiming to reduce contact resistance and enhance device performance. Using density functional theory (DFT) and non-equilibrium Green's function (NEGF)- based first-principles calculations, we examine the structural, electronic, and quantum transport properties of Au-contacted, metal-doped MoS2. Our results indicate that Cd, Re, and Ru dopants significantly improve the structural stability and electronic properties of MoS2. Specifically, formation energy calculations show that Cd and Re are stable at hollow sites, while Ru prefers bond sites. Remarkably, Au-Ru-MoS2-based device exhibits tunnel resistance (RT ) up to 4.82 ohm-um. Furthermore, a dual-gated Au-Ru-MoS2 field effect transistor (FET) demonstrates an impressive Ion/Ioff ratio of 10^8 at Vgs of 2 V, highlighting its potential for nano-switching applications.