Contactless Microwave Characterization of Encapsulated Graphene p−n Junctions

Abstract

Accessing intrinsic properties of a graphene device can be hindered by the influence of contact electrodes. Here, we capacitively couple graphene devices to superconducting resonant circuits and observe clear changes in the resonance frequency and widths originating from the internal charge dynamics of graphene. This allows us to extract the density of states and charge relaxation resistance in graphene p-n junctions without the need for electrical contacts. The presented characterization paves a fast, sensitive, and noninvasive measurement of graphene nanocircuits.

CUBIT: Capacitive qUantum BIT

“…This sandwich structure shown in Figure 1 is routinely used owing to its peculiar electronic and optical properties [17,18]. Quite interestingly, its application to a quantum-dot charge qubit design has been also demonstrated [19], which is however incompatible with the conventional superconducting quantum circuits.…”

CUBIT: Capacitive qUantum BIT

“…This sandwich structure shown in Fig. 1 is routinely used owing to its peculiar electronic and optical properties [12,13]. Quite interestingly, its application to a quantum-dot charge qubit design has been also demonstrated [14], which is however incompatible with the conventional superconducting quantum circuits.…”