Effect of Spatial Charge Inhomogeneity on 1/f Noise Behavior in Graphene (original) (raw)

Origin of 1/f noise in graphene multilayers: Surface vs. volume

Applied Physics Letters, 2013

Low-frequency noise properties of beryllium δ-doped GaAs/AlAs quantum wells near the Mott transition J. Appl. Phys. 113, 083707 (2013) Very low 1/f barrier noise in sputtered MgO magnetic tunnel junctions with high tunneling magnetoresistance J. Appl. Phys. 112, 123907 (2012) Metastable resistivity states and conductivity fluctuations in low-doped La1−xCaxMnO3 manganite single crystals Low-frequency noise with the spectral density S(f)$1/f c (f is the frequency and c % 1) is a ubiquitous phenomenon, which hampers operation of many devices and circuits. A long-standing question of particular importance for electronics is whether 1/f noise is generated on the surface of electrical conductors or inside their volumes. Using high-quality graphene multilayers, we were able to directly address this fundamental problem of the noise origin. Unlike the thickness of metal or semiconductor films, the thickness of graphene multilayers can be continuously and uniformly varied all the way down to a single atomic layer of graphene-the actual surface. We found that 1/f noise becomes dominated by the volume noise when the thickness exceeds 7atomiclayers(7 atomic layers (7atomiclayers(2.5 nm). The 1/f noise is the surface phenomenon below this thickness. The obtained results are important for continuous downscaling of conventional electronics and for the proposed graphene applications in sensors and communications. V C 2013 American Institute of Physics. [http://dx.

Electrical Noise and Transport Properties of Graphene

Journal of Low Temperature Physics, 2013

We present a study of the noise properties of single-layer exfoliated graphene as a function of gate bias. A tunnel/trap model is presented based on the interaction of graphene electrons with the underlying substrate. The model incorporates trap position, energy, and barrier height for tunneling into a given trap-along with the band-structure of the graphene-and is in good accord with the general characteristics of the data.

Charge Noise in Graphene Transistors

Nano Letters, 2010

We report an experimental study of 1/f noise in liquid-gated graphene transistors. We show that the gate dependence of the noise is well described by a charge-noise model, whereas Hooge's empirical relation fails to describe the data. At low carrier density, the noise can be attributed to fluctuating charges in close proximity to the graphene, while at high carrier density it is consistent with noise due to scattering in the channel. The charge noise power scales inversely with the device area, and bilayer devices exhibit lower noise than single-layer devices. In air, the observed noise is also consistent with the charge-noise model.

Low-Frequency Noise in Graphene Transistors

2009

We present the results of the experimental investigation of the low-frequency noise in three-terminal bilayer graphene devices. The quality of graphene layers has been verified with micro-Raman spectroscopy. Back-gated devices were fabricated using electron beam lithography and evaporation. The back-gate was used to adjust electrical conductivity through the graphene layer placed on top of Si/SiO 2 substrate. The charge neutrality point for examined devices was∼10 V. The noise spectral density was rather low (on the order of ∼10E −23-10E −22 A 2 /Hz at frequency of 1 kHz).The noise reveals generationrecombination (G-R) bulges. Presence of G-R bulges and deviation from the 1/f spectrum suggest that the noise is of carrier-number fluctuation origin due to carrier trapping by defects [1].The low values of the low-frequency noise add validity to the proposed electronic applications of graphene. [1] Q. Shao et al., IEEE EDL (2008).

Strong Suppression of Electrical Noise in Bilayer Graphene Nanodevices

Nano Letters, 2008

Low-frequency 1/f noise is ubiquitous, and dominates the signal-to-noise performance in nanodevices. Here we investigate the noise characteristics of single-layer and bilayer graphene nanodevices, and uncover an unexpected 1/f noise behavior for bilayer devices. Graphene is a single layer of graphite, where carbon atoms form a 2D honeycomb lattice. Despite the similar composition, bilayer graphene (two graphene monolayers stacked in the natural graphite order) is a distinct 2D system with a different band structure and electrical properties. In graphene monolayers, the 1/f noise is found to follow Hooge's empirical relation with a noise parameter comparable to that of bulk semiconductors. However, this 1/f noise is strongly suppressed in bilayer graphene devices, and exhibits an unusual dependence on the carrier density, different from most other materials. The unexpected noise behavior in graphene bilayers is associated with its unique band structure that varies with the charge distribution among the two layers, resulting in an effective screening of potential fluctuations due to external impurity charges. The findings here point to exciting opportunities for graphene bilayers in low-noise applications. arXiv:0801.4576v1 [cond-mat.mtrl-sci] 29 Jan 2008 Ultra-thin graphite films have attracted strong scientific and technological interest as truly 2D transport systems [3, 4, 5] with exceptional carrier mobilities.[6, 7] While a singlelayer 2D graphene is a zero-gap semiconductor, which is not suitable for certain applications, a wealth of different band structures emerge in nanoscale graphene that exhibit band gaps and distinct electrical properties [8] desirable for various device applications, such as metallic interconnects, [7] field-effect transistors [9, 10] and single-charge devices. [4] In addition, both experimental [9, 11] and theoretical [12] studies have shown that the transport properties of

Low-frequency electronic noise in the double-gate single-layer graphene transistors

Applied Physics Letters, 2009

The authors report the results of an experimental investigation of the low-frequency noise in the double-gate graphene transistors. The back-gate graphene devices were modified via addition of the top gate separated by ϳ20 nm of HfO 2 from the single-layer graphene channels. The measurements revealed low flicker noise levels with the normalized noise spectral density close to 1 / f ͑f is the frequency͒ and Hooge parameter ␣ H Ϸ 2 ϫ 10 −3 . The analysis of noise spectral density dependence on the top and bottom gate biases helped to elucidate the noise sources in these devices. The obtained results are important for graphene electronic and sensor applications.

Understanding the bias dependence of low frequency noise in single layer graphene FETs

Nanoscale, 2018

This letter investigates the bias-dependent low frequency noise of single layer graphene field-effect transistors. Noise measurements have been conducted with electrolyte-gated graphene transistors covering a wide range of gate and drain bias conditions for different channel lengths. A new analytical model that accounts for the propagation of the local noise sources in the channel to the terminal currents and voltages is proposed in this paper to investigate the noise bias dependence. Carrier number and mobility fluctuations are considered as the main causes of low frequency noise and the way these mechanisms contribute to the bias dependence of the noise is analyzed in this work. Typically, normalized low frequency noise in graphene devices has been usually shown to follow an M-shape dependence versus gate voltage with the minimum near the charge neutrality point (CNP). Our work reveals for the first time the strong correlation between this gate dependence and the residual charge w...

Quantum Noise and Asymmetric Scattering of Electrons and Holes in Graphene

Nano Letters, 2014

We present measurements of quantum interference noise in double-gated single layer graphene devices at low temperatures. The noise characteristics show a nonmonotonic dependence on carrier density, which is related to the interplay between charge inhomogeneity and different scattering mechanisms. Linearly increasing 1/f noise at low carrier densities coincides with the observation of weak localization, suggesting the importance of short-range disorder in this regime. Using perpendicular and parallel p−n junctions, we find that the observed asymmetry of the noise with respect to the Dirac point can be related to asymmetric scattering of electrons and holes on the disorder potential.

Resistance Noise in Electrically Biased Bilayer Graphene

Physical Review Letters, 2009

We demonstrate that the low-frequency resistance fluctuations, or noise, in bilayer graphene is strongly connected to its band structure, and displays a minimum when the gap between the conduction and valence band is zero. Using double-gated bilayer graphene devices we have tuned the zero gap and charge neutrality points independently, which offers a versatile mechanism to investigate the low-energy band structure, charge localization and screening properties of bilayer graphene.