Charge carrier density noise in graphene: effect of localized/delocalized traps

TL;DR

This study models charge carrier density noise in graphene caused by substrate traps, revealing a near 1/f noise spectrum influenced by trap occupancy and temperature, relevant for quantum electronic applications.

Contribution

The paper introduces a simplified model distinguishing localized and delocalized traps in graphene, analyzing their impact on charge noise spectrum and temperature dependence.

Findings

Charge noise follows a 1/f^ close to unity.

Noise amplitude depends on trap energy distribution and temperature.

Spin occupancy of traps affects temperature dependence only secondarily.

Abstract

Graphene-based devices show $1/f$ low-frequency noise in several electronic transport properties, such as mobility and charge carrier concentration. The recent outburst of experimental studies on graphene-based devices integrated into circuit quantum electrodynamics systems has rekindled the interest in low-frequency charge noise. We investigate charge carrier density noise in graphene within the McWorther model where noise is induced by electron traps in the substrate. We focus on the large doping regime and introduce a simple modelization of the effect of localized/delocalized traps in terms of single/double spin occupancy of trap states. We find that in both cases the charge carrier spectrum of graphene obeys the $1/f^\alpha$ power-law behavior where $\alpha$ is very close to the unity, and for each case we evaluate the deviation $\beta=1-\alpha$. The amplitude of the noise is found to depend on the trap energy distribution and on temperature. Single/double spin occupancy of trap states influences the temperature dependence of noise amplitude only to second order.