Raman scattering and low-frequency noise in epitaxial graphene chips

Eliseyev, Ilya A.; Usikov, A.; Lebedev, S. P.; Роенков, А. Д.; Пузык, М. В.; Zubov, A. V.; Makarov, Yu.N.; Лебедев, А. А.; Шабунина, Е. И.; Dementev, P. A.; Смирнов, А. Н.; Shmidt, N. M.

doi:10.1088/1742-6596/1697/1/012130

Cited by 5 publications

(3 citation statements)

References 12 publications

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“…Indeed, for the EG417-C5, Е5, Е7 chips showing different values of excess noise, there are regions with frequency dependencies SU ~1/f γ having different values of γ up to 1.4 with a maximum SU value at 1.22 Hz for the EG417-C5 chip as shown in Figure 3b. Earlier, we have observed that the dependence of SU ~1/fγ (γ > 1) in graphene films and the chips is consistent with the Raman spectra data that demonstrate an inhomogeneous distribution of compressive stresses in graphene [32]. Studying of graphene topography in these chips reveals cracks in graphene shown in Figure 4a-c, and d (EG417-Е7, -C5) and extended For the remaining 18% of chips, the spread of S U values was in the range of 6 × 10 −13 to 8 × 10 −11 V 2 /Hz (Figure 3a).…”

Section: Resultssupporting

confidence: 89%

Quality Assessment of Processed Graphene Chips for Biosensor Application

et al. 2023

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The quality of graphene intended for use in biosensors was assessed on manufactured chips using a set of methods including atomic force microscopy (AFM), Raman spectroscopy, and low-frequency noise investigation. It is shown that local areas of residues on the graphene surface, formed as a result of the interaction of graphene with a photoresist at the initial stage of chip development, led to a spread of chip resistance (R) in the range of 1–10 kOhm and to an increase in the root mean square (RMS) roughness up to 10 times, which can significantly worsen the reproducibility of the parameters of graphene chips for biosensor applications. It was observed that the control of the photoresist residues after photolithography (PLG) using AFM and subsequent additional cleaning reduced the spread of R values in chips to 1–1.6 kOhm and obtained an RMS roughness similar to the roughness in the graphene film before PLG. Monitoring of the spectral density of low-frequency voltage fluctuation (SU), which provides integral information about the system of defects and quality of the material, makes it possible to identify chips with low graphene quality and with inhomogeneously distributed areas of compressive stresses by the type of frequency dependence SU(f).

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Section: Resultssupporting

confidence: 89%

Quality Assessment of Processed Graphene Chips for Biosensor Application

et al. 2023

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“…Reproducibility issues relating to the structural and physicochemical properties of graphene resistances are discussed in [ 1 , 7 , 11 , 12 ]. The inhomogeneity of the properties of graphene films over the chip area has led to the need to use several duplicate resistors in one biosensor.…”

Section: Introductionmentioning

confidence: 99%

“…The inhomogeneity of the properties of graphene films over the chip area has led to the need to use several duplicate resistors in one biosensor. This makes it possible to neutralize the effect of inhomogeneity of resistance values on the results of virus detection by the biosensor [ 1 , 7 , 11 ]. These works show that the hook effect [ 13 ] related to a nonlinear dependence of detected signals versus analyte concentration may cause the lack of reproducibility of detection.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Morphology and Electrical Properties of Graphene Used in the Development of Biosensors for Detection of Influenza Viruses

et al. 2021

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In this study, we discuss the mechanisms behind changes in the conductivity, low-frequency noise, and surface morphology of biosensor chips based on graphene films on SiC substrates during the main stages of the creation of biosensors for detecting influenza viruses. The formation of phenylamine groups and a change in graphene nano-arrangement during functionalization causes an increase in defectiveness and conductivity. Functionalization leads to the formation of large hexagonal honeycomb-like defects up to 500 nm, the concentration of which is affected by the number of bilayer or multilayer inclusions in graphene. The chips fabricated allowed us to detect the influenza viruses in a concentration range of 10−16 g/mL to 10−10 g/mL in PBS (phosphate buffered saline). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) revealed that these defects are responsible for the inhomogeneous aggregation of antibodies and influenza viruses over the functionalized graphene surface. Non-uniform aggregation is responsible for a weak non-linear logarithmic dependence of the biosensor response versus the virus concentration in PBS. This feature of graphene nano-arrangement affects the reliability of detection of extremely low virus concentrations at the early stages of disease.

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Investigation of electrolysis-related modification of graphene films in biosensors

Eliseyev

Usikov

Lebedev

et al. 2021

J. Phys.: Conf. Ser.

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In this work, the modification of the surface parameters of graphene chips after electrolysis treatment in a NaClO4 aqueous solution has been studied. Two electrolysis modes have been analysed. In the first one, a negative potential (-0.2 V) is applied to the graphene chips, while in the second one the potential is positive (0.8 V). Investigation using a number of techniques including atomic force microscopy, Kelvin probe force microscopy, Raman spectroscopy, measurements of current-voltage characteristics and low-frequency noise has shown that the electrolysis mode with application of a positive potential on graphene chips decreases the 1/f noise and allows one to obtain a uniform surface potential distribution while leaving the graphene structure undamaged. The results of this study help to understand the efficiency and reproducibility of the procedure for electrolysis treatment of graphene chips.

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Raman scattering and low-frequency noise in epitaxial graphene chips

Cited by 5 publications

References 12 publications

Quality Assessment of Processed Graphene Chips for Biosensor Application

Quality Assessment of Processed Graphene Chips for Biosensor Application

Investigation of the Morphology and Electrical Properties of Graphene Used in the Development of Biosensors for Detection of Influenza Viruses

Investigation of electrolysis-related modification of graphene films in biosensors

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