Effect of boron nitride defects and charge inhomogeneity on 1/f noise in encapsulated graphene

TL;DR

This study investigates 1/f noise in encapsulated graphene with hBN, revealing how defects and charge inhomogeneity influence noise behavior, especially near the Dirac point and at specific doping levels.

Contribution

The paper demonstrates the impact of boron nitride defects and charge inhomogeneity on 1/f noise in encapsulated graphene, highlighting a new physical mechanism for noise peaks.

Findings

Smaller noise magnitude compared to graphene on Si/SiO2

Pronounced noise peak at Fermi energy in electron doping

Characteristic M-shape noise near Dirac point

Abstract

Low frequency 1/f noise is investigated in graphene, encapsulated between hexagonal boron nitride (hBN) substrate in dual gated geometry. The overall noise magnitude is smaller as compared to graphene on Si/SiO2 substrate. The noise amplitude in the hole doped region is independent of carrier density while in the electron doped region, a pronounced peak is observed, at Fermi energy, EF ~ 90 meV. The physical mechanism of the anomalous noise peak in the electron doped region is attributed to the impurity states originating from the Carbon atom replacing the Nitrogen site in hBN crystal. Furthermore, the noise study near Dirac point shows characteristic "M-shape", which is found to be strongly correlated with the charge inhomogeneity region near Dirac point.