Electrical Low-Frequency 1/f^γ Noise Due to Surface Diffusion of Scatterers on an Ultra-low-Noise Graphene Platform

Abstract

Low-frequency 1/f γ noise is ubiquitous, even in high-end electronic devices. Recently, it was found that adsorbed O2 molecules provide the dominant contribution to flux noise in superconducting quantum interference devices. To clarify the basic principles of such adsorbate noise, we have investigated low-frequency noise, while the mobility of surface adsorbates is varied by temperature. We measured low-frequency current noise in suspended monolayer graphene Corbino samples under the influence of adsorbed Ne atoms. Owing to the extremely small intrinsic noise of suspended graphene, we could resolve a combination of 1/f γ and Lorentzian noise induced by the presence of Ne. We find that the 1/f γ noise is caused by surface diffusion of Ne atoms and by temporary formation of few-Ne-atom clusters. Our results support the idea that clustering dynamics of defects is relevant for understanding of 1/f noise in metallic systems.

Strong magnetoresistance in a graphene Corbino disk at low magnetic fields

“…In the vicinity of the Dirac point at 4 K, we find a high sensitivity of resistance variation with respect to magnetic field dR/dB = 12.5 k /T at B = 0.15 T. According to our current-noise measurements [24] yielding S I = 10 −23 A 2 /Hz at 1 kHz for the same sample at 10 μA, we may estimate a magnetic field sensitivity of 60 nT/ √ Hz for our device at 4 K. This sensitivity is excellent when compared with graphene Hall magnetometers, since our result is on par with magnetic field sensitivities of devices working in 20 times larger magnetic fields [46].…”

“…Our work demonstrates a magnetic field sensitivity on the order of 60 nT/ √ Hz at 4 K in a background field of 0.15 T. For a detailed investigation of noise in the suspendedgraphene Corbino samples studied in the present work, see Ref. [24].…”

Critical current fluctuations in graphene Josephson junctions

“…Part of the 1/f noise originates from charge carrier mobility fluctuations which may arise a.o. due to substrate roughness, ripples in graphene, gas adsorbates, or coupling to phonons 2,7,[13][14][15] . In h-BN encapsulated graphene samples, a weak gate modulation in the current fluctuation is seen with peak at Dirac point and saturation at higher charge density 16,17 .…”

Electrical low-frequency $1/f^γ$ noise due to surface diffusion of scatterers on an ultra low noise graphene platform

“…The applied gate voltage V g was employed to determine the charge carrier density according to n = (V g − V D g )C g e, where V D g denotes the gate voltage value of the Dirac point. Measurements of zero-bias resistance R 0 (V g ) (see the SI 30 ) yielded the field-effect mobility µ F E ∼ 10 5 cm 2 /Vs Fig. 1 illustrates the basic influence of neon gas on our graphene samples.…”

“…We identify E a1 = E a as the adsorption energy of neon onto graphene, while the latter E a2 = E b is identified as describing trap states at the boundary (see Sect II of SI 30 ).…”