Transit-time resonances enabling amplification and generation of terahertz radiation in periodic graphene p-i-n structures with the Zener-Klein interband tunneling

TL;DR

This paper explores how transit-time resonances in graphene p-i-n structures with Zener-Klein tunneling can enable amplification and generation of terahertz radiation through negative conductance and resonant effects.

Contribution

It introduces a novel design of periodic graphene p-i-n structures that utilize transit-time resonances for terahertz amplification and generation, combining Zener-Klein tunneling with TT negative conductance.

Findings

Transit-time resonances enable THz signal amplification.

Periodic graphene structures can serve as THz sources.

Negative dynamic conductance occurs in specific frequency ranges.

Abstract

The Zener-Klein (ZK) interband tunneling in graphene layers (GLs) with the lateral n-i-n and p-i-n junctions results in the nonlinear I-V characteristics that can be used for the rectification and detection of the terahertz (THz) signals. The transit time delay of the tunneling electrons and holes in the depletion regions leads to the phase shift between the THz current and THz voltage causing the negative dynamic conductance in a certain frequency range and resulting in the so-called transit-time (TT) instability. The combination of the ZK tunneling and the TT negative dynamic conductance enables resonant THz detection and the amplification and generation of THz radiation. We propose and evaluate the THz devices based on periodic cascade GL p-i-n structures exhibiting the TT resonances (GPIN-TTDs). Such structures can serve as THz amplifiers and, being placed in a Fabri-Perot cavity, or coupled to a THz antenna or using a ring oscillator connection, as THz radiation sources.