WSe2/Pd Schottky diode combining van der Waals integrated and evaporated metal contacts

Metal–semiconductor junctions are at the heart of modern electronics. Various two-dimensional materials (2D) based electronic devices have been reported. However, Ohmic contacts between evaporated metal contacts and semiconducting 2D materials are still hard to achieve. Thus, design and fabrication of Schottky diodes based on layered WSe2 remain challenging. Here, we report a doping-free strategy to achieve Ohmic contacts in WSe2 diodes via van der Waals (vdW) contacts. We designed and fabricated vertical WSe2/Pd Schottky diodes, in which Ohmic and Schottky junctions can be realized simultaneously via vdW contacts and evaporated contacts, respectively. The specific contact resistance of the vdW contact is about 74.5 kΩ·μm2. The Schottky diodes exhibit strong rectification behavior with rectification ratio up to 105.