Reduction of 1/f noise in graphene after electron-beam irradiation

Abstract

We investigated the effect of the electron-beam irradiation on the level of the low-frequency 1/f noise in graphene devices. It was found that 1/f noise in graphene reveals an anomalous characteristic -it reduces with increasing concentration of defects induced by irradiation. The increased amount of structural disorder in graphene under irradiation was verified with microRaman spectroscopy. The bombardment of graphene devices with 20-keV electrons reduced the noise spectral density, S I /I 2 (I is the source-drain current) by an order-of magnitude at the radiation dose of 10 4 C/cm 2 . Our theoretical considerations suggest that the observed noise reduction after irradiation can be more readily explained if the mechanism of 1/f noise in graphene is related to the electron-mobility fluctuations. The obtained results are important for the proposed graphene applications in analog, mixed-signal and radio-frequency systems, integrated circuit interconnects and sensors.Noise Suppression in Graphene, UCR -RPI -Ioffe (2012) 3The level of the flicker 1/f noise [1] is one of the key metrics that each new material has to pass before it can be used for practical devices (f is the frequency) [2]. Graphene [3] has shown a great potential for applications in high-frequency communications [4][5], analog circuits [6] and sensors [7][8]. The envisioned applications require a low level of 1/f noise, which contributes to the phase-noise of communication systems [2] and limits the sensor sensitivity [7]. Despite significant research efforts [9][10][11][12][13][14][15] there is still no conventionally accepted model for physical mechanisms behind 1/f noise in graphene. Correspondingly, no comprehensive methods for 1/f noise suppression in graphene devices have been developed.In this Letter we show that 1/f noise in graphene reveals an anomalous characteristic -it reduces with increasing concentration of defects induced by irradiation. We found that bombardment of graphene devices with 20-keV electrons can reduce the noise spectral density, S I /I 2 (I is the source-drain current) by an order-of magnitude at the radiation dose (RD) of 10 4 C/cm 2 . Our theoretical analysis suggests that the observed noise suppression after introduction of defects can be explained if the mechanism of 1/f noise in graphene is related to the electron-mobility fluctuations rather than to the carrier-density fluctuations. Apart from contributing to understanding the physics behind 1/f noise in graphene our results can possibly offer a practical method for noise reduction in various graphene devices. Graphene is relatively susceptible to the electron and ion bombardment owing to its single-atom thickness [21][22][23]. Electron irradiation can introduce different types of defects in graphene Noise Suppression in Graphene, UCR -RPI -Ioffe (2012) 5 depending on the beam energy and local environment, e.g. presence of organic contaminants. For this study we selected the electron energy of 20 keV in order to exclude the severe knock-on damage to ...

Low-frequency 1/f noise in graphene devices

“…Another approach is related to the electron irradiation treatment of graphene channels [49]. It was recently reported that 1/f noise in graphene reveals an interesting characteristic -it reduces after irradiation (see Figure 2 (c-d)).…”

“…It was recently reported that 1/f noise in graphene reveals an interesting characteristic -it reduces after irradiation (see Figure 2 (c-d)). It was experimentally observed that bombardment of graphene devices with the low-energy 20-keV electrons, which induce defects but do not eject carbon atoms, can reduce S I /I 2 by an order-of magnitude at a radiation dose of 10 4 C/cm 2 [49].…”

Graphene versus MoS2: A short review

“…More measurements are needed to examine the nanoresonator properties, such as the mass sensitivity. Furthermore, the sensor application of the nanoresonators depends on the level of low frequency 1/f noise, which is a limiting factor for communication applications and sensor sensitivity as well as the selectivity of graphene and MoS 2 nanoresonators [103][104][105][106][107][108][109].…”

Ultra low 1/f noise in suspended bilayer graphene

“…It was previously reported in Ref. 23 that electron beam irradiation can lead to a reduction of 1/f noise level. However, this reduction of noise is unlikely in the case of suspended part of the flake which resides far away from the main source of secondary electrons, the Si substrate, and is thus more protected than graphene under the contacts.…”