Van der Waals Heterostructure Contact Strategy for Barrier‐Free 2D Complementary Transistors

Incorporating atomically thin 2D semiconductors (2DSCs) into the vertical complementary field‐effect transistors (CFETs) is of great significance in enabling devices to break through the sub‐nanometer scaling limit. However, due to the lack of effective doping technology and the difficult‐to‐control electrode interface, simultaneously realizing high‐performance p‐type and n‐type devices using a single metal electrode presents great challenges for 2D‐CFETs design. In this study, an innovative electrical contact strategy is proposed by constructing van der Waals heterojunction (vdWH) using 2DSCs to regulate the electrical contact properties between the metal electrode and 2DSC channel. First‐principles calculations reveal that degenerate or quasi‐degenerate complementary doping is achieved in a series of transition metal dichalcogenides (TMDs) by designing (quasi‐)broken‐gap vdWHs and utilizing their interlayer charge transfer. Metal‐2DSC contact barriers can be effectively regulated by introducing 2DSC intercalation and constructing vdWH. P‐type (quasi‐)Ohmic contacts are realized between Au electrode and various TMD channels, as well as between WTe 2 channel and different metal electrodes. Moreover, quantum transport simulations present the remarkable on‐current over 10 2 µA µm −1 in both p‐type and n‐type 2D‐FETs by employing the vdWH and metal‐vdWH electrodes. The proposed vdWH strategy is applicable to various metal‐2DSC contacts and will shed light on future high‐performance 2D‐CFET integrations.