Active graphene–silicon hybrid diode for terahertz waves

TLDR

Controlling terahertz propagation in graphene promises novel electronics‑photonics convergence, and a diode permits unidirectional current flow based on voltage polarity. The authors demonstrate an active terahertz diode by integrating a graphene–silicon hybrid film and applying simultaneous optical and electrical excitations. The hybrid diode transmits terahertz waves under positive bias and attenuates them under low negative bias, achieving an 83 % transmission modulation and showing promise for broadband THz modulators and switchable plasmonic/metamaterial devices.

Abstract

Abstract Controlling the propagation properties of the terahertz waves in graphene holds great promise in enabling novel technologies for the convergence of electronics and photonics. A diode is a fundamental electronic device that allows the passage of current in just one direction based on the polarity of the applied voltage. With simultaneous optical and electrical excitations, we experimentally demonstrate an active diode for the terahertz waves consisting of a graphene–silicon hybrid film. The diode transmits terahertz waves when biased with a positive voltage while attenuates the wave under a low negative voltage, which can be seen as an analogue of an electronic semiconductor diode. Here, we obtain a large transmission modulation of 83% in the graphene–silicon hybrid film, which exhibits tremendous potential for applications in designing broadband terahertz modulators and switchable terahertz plasmonic and metamaterial devices.