Effect of self-consistent electric field on characteristics of graphene p-i-n tunneling transit-time diodes

TL;DR

This paper presents a comprehensive device model for graphene-based p-i-n tunneling transit-time diodes, analyzing how self-consistent electric fields influence their electrical characteristics and potential for terahertz applications.

Contribution

It introduces a novel model for graphene tunneling diodes that incorporates self-consistent electric fields and explores their frequency-dependent admittance behavior.

Findings

Admittance real part can be negative at certain frequencies.

Negative admittance range extends to terahertz frequencies for short i-sections.

Device structure optimization enables potential terahertz oscillator applications.

Abstract

We develop a device model for p-i-n tunneling transit-time diodes based on single- and multiple graphene layer structures operating at the reverse bias voltages. The model of the graphene tunneling transit-time diode (GTUNNETT) accounts for the features of the interband tunneling generation of electrons and holes and their ballistic transport in the device i-section, as well as the effect of the self-consistent electric field associated with the charges of propagating electrons and holes. Using the developed model, we calculate the dc current-voltage characteristics and the small-signal ac frequency-dependent admittance as functions of the GTUNNETT structural parameters, in particular, the number of graphene layers and the dielectric constant of the surrounding media. It is shown that the admittance real part can be negative in a certain frequency range. As revealed, if the i-section somewhat shorter than one micrometer, this range corresponds to the terahertz frequencies. Due to the effect of the self-consistent electric field, the behavior of the GTUNNETT admittance in the range of its negativity of its real part is rather sensitive to the relation between the number of graphene layers and dielectric constant. The obtained results demonstrate that GTUNNETTs with optimized structure can be used in efficient terahertz oscillators.