Suppression of 1/f Noise in Near-Ballistic h-BN-Graphene-h-BN Heterostructure Field-Effect Transistors

TL;DR

This study demonstrates significant suppression of 1/f noise in graphene transistors encapsulated with hexagonal boron nitride, enhancing their potential for electronic and optoelectronic applications.

Contribution

The paper introduces a method of reducing 1/f noise in graphene transistors by encapsulating them with h-BN, achieving a five to tenfold noise reduction compared to non-encapsulated devices.

Findings

Noise spectral density normalized to area is suppressed to 5 x 10^-9 μm^2 Hz^-1.

Encapsulation with h-BN reduces noise by a factor of 5 to 10.

Charge carrier screening from traps in SiO2 is the physical mechanism for noise suppression.

Abstract

We have investigated low-frequency 1/f noise in the boron nitride - grapheme - boron nitride heterostructure field - effect transistors on Si/SiO2 substrates (f is a frequency). The device channel was implemented with a single layer graphene encased between two layers of hexagonal boron nitride. The transistors had the charge carrier mobility in the range from 30000 to 36000 cm2/Vs at room temperature. It was established that the noise spectral density normalized to the channel area in such devices can be suppressed to 5 x 10^-9 {\mu}m2 Hz^-1, which is a factor of x5 - x10 lower than that in non-encapsulated graphene devices on Si/SiO2. The physical mechanism of noise suppression was attributed to screening of the charge carriers in the channel from traps in SiO2 gate dielectric and surface defects. The obtained results are important for the electronic and optoelectronic applications of graphene.