Clean Interface Contact Using a ZnO Interlayer for Low-Contact-Resistance MoS2 Transistors

Two-dimensional transition metal dichalcogenides (TMDCs) have emerged as promising materials for next-generation electronics due to their excellent semiconducting properties. However, high contact resistance at metal–TMDC interface plagues the realization of high-performance devices. Here, an effective metal–interlayer–semiconductor contact is demonstrated, wherein an ultrathin ZnO interlayer is inserted between metal electrode and MoS2, providing damage-free and clean interfaces at electrical contacts. Using TEM imaging, we show that the contact interfaces were atomically clean without any apparent damages. Compared to conventional Ti/MoS2 contacts, the MoS2 devices with Ti/ZnO/MoS2 contact exhibit a very low contact resistance of 0.9 kΩ µm. These improvements are attributed to the following mechanisms: (a) Fermi-level depinning at metal/MoS2 interface by reducing interface disorder, and (b) presence of interface dipole at metal/ZnO interface, consequently reducing the Schottky barrier and contact resist...