Type-III Van Der Waals Stacking Induced Ohmic Contacts: A Contact Strategy for 2-D Complementary Electronics

The low-resistance contact at metal-semiconductor interfaces is extremely important for the improvement and assembly of 2-D electronics. However, the Schottky barrier is hardly removed in complementary transistors, suffering from the Fermi-level pinning (FLP) in conventional metal-semiconductor interfaces and the limited working functions of semimetals. Here, we propose a novel contact strategy to achieve low-resistance contacts, by using the type-III heterostructures as semi-metallic electrodes and two 2-D materials which forms the heterostructure as n- and p-type channels, respectively. The band alignment ensures energy level matching between the electrodes and channels, and the low density of states (DOS) of electrodes at the Fermi level suppress the metal-induced gap states (MIGS) to avoid FLP. Through first-principles calculations, we achieve Ohmic contacts in six different type-III systems for both n- and p-type devices. This work proposes a feasible approach for low-resistance contacts in 2-D complementary electronics, and broadens the horizon for semimetal-semiconductor contacts.