Investigation of electrical properties of contact between Molybdenum disulfide and different metals

With growing interest in the application of molybdenum disulfide (MoS₂) into high performance transistors, understanding its contact with different metals is important. Improper MoS₂/metal contact render the device high contact impedance, which leads to insufficient charge injection efficiency and as a result, bad device performance. In this study, to characterize electrical properties in MoS₂/metal contact with commonly used metal: gold (Au), palladium (Pd), nickel (Ni) and titanium (Ti), Kelvin probe force microscopy (KPFM) is utilized to mapping the surface potential (SP) distribution in such contacts. It is concluded from the characterization results that band alignment between MoS₂ and different metals are not determined solely by band structure of MoS₂ and work function of the contact metals, instead, a special phenomenon--partial fermi level pinning appears in such contacts. Also, we notice that different metal processes considerable different topographical roughness, which may have great influence on the charge injection efficiency in the contacts.