Efforts towards a low loss all van der Waals parallel plate capacitor for quantum devices

Quantum devices such as qubits require ultra low loss capacitance elements. Conventional parallel plate capacitors have been unable to fulfill this need due to bulk and interfacial losses, necessitating the use of coplanar capacitors with extremely large footprints. Single crystal van der Waals materials, grown with extremely low defect densities, can be stacked to create heterostructures with ultra-clean laminated interfaces. Here we report efforts to fabricate and characterize electrically an all van der Waals (vdW) parallel plate capacitor with low loss at gigahertz frequencies. Using exfoliated vdW materials, such as niobium diselenide (NbSe2), and hexagonal boron nitride (h-BN), our process allows us to create capacitors with atomically flat, ultra clean interfaces, and dramatically reduced footprints when compared to conventional coplanar capacitors.