Reconfigurable Diodes Based on Vertical WSe₂ Transistors with van der Waals Bonded Contacts

New device concepts can increase the functionality of scaled electronic devices, with reconfigurable diodes allowing the design of more compact logic gates being one of the examples. In recent years, there has been significant interest in creating reconfigurable diodes based on ultra-thin transition metal dichalcogenide crystals. Thanks to their large surface areas, these devices were constructed under planar geometry and device characteristics are controlled by electrostatic gating through rather complex two independent local gates or ionic-liquid doping process. In this talk, we demonstrate similar reconfigurable diode actions in a WSe₂ transistor by only utilizing van der Waals bonded graphene and Co/ h-BN contacts. Towards this, we first characterize the charge injection efficiencies into WSe₂ by graphene and Co/h-BN contacts. While Co/h-BN contact results in nearly Schottky barrier-free charge injection, graphene/WSe₂ interface has an average barrier height of ~ 80 meV. By taking the advantage of the electrostatic transparency of graphene and the different work-function values of graphene and Co/h-BN, we construct vertical devices where we demonstrate different gate-tunable diode actions. Our device architecture reveals the opportunities for exploring new device concepts.