Regularities of Electrical Conductivity of Monolayer Graphene Nanomesh with Round Holes

2021 ◽  
Vol 23 (5) ◽  
pp. 231-237
Author(s):  
O.E. Glukhova ◽  
◽  
M.M. Slepchenkov ◽  
P.V. Barkov ◽  
◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Energy Gap ◽  
Monolayer Graphene ◽  
Current Transfer ◽  
Neck Width ◽  
Zigzag Direction ◽  
Circular Holes ◽  
Graphene Nanomesh ◽  
Density Of Electron States ◽  
Armchair Direction

This paper studies graphene nanomesh with different neck width is the smallest distance between two neighboring holes. The electrical properties of graphene nanomesh with circular holes were calculated in dependence on its neck width. For the considered structures energetical characteristics including energy gap (Egap), Fermi level (Ef), and density of electron states (DOS) were found. It was established that graphene nanomesh demonstrated both metallic and semiconductor types of conductivity when the neck width was increased along the zigzag direction. In the case of increasing the neck width along armchair direction, graphene nanomesh demonstrated only a metallic type of conductivity. It was observed the anisotropy of electrical conductivity depending on the direction along which the current transfer was carried out.

scholarly journals The Effect of Hydrogen on the Electrical Properties of the Graphene Nanomeshes

2020 ◽  
Vol 6 (2) ◽  
pp. 35
Author(s):  
Pavel V. Barkov ◽  
Michael M. Slepchenkov ◽  
Olga E. Glukhova
Keyword(s):  
Electrical Conductivity ◽  
Energy Gap ◽  
Electronic Conductivity ◽  
Electron Work Function ◽  
Current Transfer ◽  
Hydrogen Atoms ◽  
Turn On ◽  
Hydrogenated Graphene ◽  
In Silico Study ◽  
Graphene Nanomesh

This paper is devoted to the in silico study of the electronic properties and electrical conductivity of hydrogenated graphene nanomesh (GNM). It is found that the conductivity of GNM can be controlled by varying the type of hydrogenation. Due to the hydrogenation of the nanohole edges by one or two hydrogen atoms, the energy gap can be changed, the anisotropy of the electrical conductivity can be enhanced, and the electron work function can be controlled. By varying the type of hydrogenation, it is possible to form conductive and insulating paths on 2D GNM. Thus, a certain combination of the sp2- and sp3-topologies of the GNM edge atoms allows one to fully “turn off” the electronic conductivity in all directions or, conversely, “turn on” the desired direction for current transfer.

scholarly journals Holey Graphene: Topological Control of Electronic Properties and Electric Conductivity

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1074
Author(s):  
Pavel V. Barkov ◽  
Olga E. Glukhova
Keyword(s):  
Electrical Conductivity ◽  
Fermi Level ◽  
Electric Conductivity ◽  
Energy Gap ◽  
Local Density ◽  
Electronic States ◽  
Current Transfer ◽  
Neck Width ◽  
Density Of Electronic States ◽  
Semiconductor Type

This paper studies holey graphene with various neck widths (the smallest distance between two neighbor holes). For the considered structures, the energy gap, the Fermi level, the density of electronic states, and the distribution of the local density of electronic states (LDOS) were found. The electroconductive properties of holey graphene with round holes were calculated depending on the neck width. It was found that, depending on the neck width, holey graphene demonstrated a semiconductor type of conductivity with an energy gap varying in the range of 0.01–0.37 eV. It was also shown that by changing the neck width, it is possible to control the electrical conductivity of holey graphene. The anisotropy of holey graphene electrical conductivity was observed depending on the direction of the current transfer.

scholarly journals Fabrication of Graphene Nanomesh FET Terahertz Detector

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 641
Author(s):  
Yuan Zhai ◽  
Yi Xiang ◽  
Weiqing Yuan ◽  
Gang Chen ◽  
Jinliang Shi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Energy Gap ◽  
Coupling Efficiency ◽  
High Sensitivity ◽  
Fabrication Process ◽  
Monolayer Graphene ◽  
Terahertz Waves ◽  
Wet Process ◽  
Graphene Nanomesh ◽  
Thz Detector

High sensitivity detection of terahertz waves can be achieved with a graphene nanomesh as grating to improve the coupling efficiency of the incident terahertz waves and using a graphene nanostructure energy gap to enhance the excitation of plasmon. Herein, the fabrication process of the FET THz detector based on the rectangular GNM (r-GNM) is designed, and the THz detector is developed, including the CVD growth and the wet-process transfer of high quality monolayer graphene films, preparation of r-GNM by electron-beam lithography and oxygen plasma etching, and the fabrication of the gate electrodes on the Si3N4 dielectric layer. The problem that the conductive metal is easy to peel off during the fabrication process of the GNM THz device is mainly discussed. The photoelectric performance of the detector was tested at room temperature. The experimental results show that the sensitivity of the detector is 2.5 A/W (@ 3 THz) at room temperature.

Simple and environment-friendly method for graphene synthesis by using ultrasound.

2021 ◽  
Vol 17 ◽  
Author(s):  
Irena Markovska ◽  
Dimitar Georgiev ◽  
Fila Yovkova ◽  
Miroslav Abrashev
Keyword(s):  
Electrical Conductivity ◽  
Raman Spectroscopy ◽  
Monolayer Graphene ◽  
Conductivity Measurements ◽  
Environment Friendly ◽  
Complex Processes ◽  
Graphene Synthesis ◽  
Pure Graphite ◽  
Ft Ir ◽  
Electrodes For Supercapacitors

Background: This paper proposes a technology for the production of monolayer graphene by an easy, accessible, and non-toxic method. Methods: For the preparation of graphene, a combination of chemical and physical (ultrasonic) treatment of the original graphite precursor (purity >99%) was applied. The precursor of graphite is placed in a beaker with a solution of KOH or H2SO4. The mixtures were homogenized well and sonicated for 4h. The applied ultrasound has a power of 120 W, frequency 40 kHz. Due to the effects of ultrasound, complex processes take place in the solutions, which leads to the formation of superfine graphene. Better results were obtained at samples treated with 2n H2SO4. The physicochemical properties of the resulting graphene were characterized mainly by Raman spectroscopy, FT-IR, TEM, SEM, and electrical conductivity measurements. Results: Our research was focused mainly on the field of nanotechnology, in particular on the synthesis of graphene, which could be used as a coating on electrodes for supercapacitors. In this connection, three series of samples were developed in which the pristine graphite was treated with 2n H2SO4, 4n H2SO4, and 6n H2SO4, respectively, and their electrical properties were measured. Conclusion: The obtained graphene shows electrical resistivity 2-3 times lower than that of the precursor of pure graphite.

Magnetotransport phenomena in layered conductors under magnetic breakdown

2017 ◽  
Vol 31 (14) ◽  
pp. 1750114
Author(s):  
O. Galbova ◽  
V. G. Peschansky ◽  
D. I. Stepanenko
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Energy Spectrum ◽  
Hydrostatic Pressure ◽  
Fermi Surface ◽  
Linear Dependence ◽  
Energy Gap ◽  
Electron Energy Spectrum ◽  
External Effects ◽  
Magnetic Breakdown

We study the transport phenomena in layered conductors with rather general electron energy spectrum placed in a high magnetic field [Formula: see text], under conditions when the distance between various sheets of the Fermi surface (FS) may become small under the external effects, such as hydrostatic pressure or impurity atom doping, and electrons can transfer from one sheet of the FS to another due to magnetic breakdown. We calculate the dependence of the in-plane electrical conductivity and magnetoresistance on magnetic field and probability of magnetic breakdown and show that the field-induced quadratic increase of the in-plane resistance in the absence of magnetic breakdown is changed by a linear dependence on [Formula: see text]. With a further reduction of the energy gap between FS sheets, the in-plane resistance is saturated.

Electron transport and conduction band structure of GaSb

1981 ◽  
Vol 59 (12) ◽  
pp. 1844-1850 ◽  
Author(s):  
Hyung Jae Lee ◽  
John C. Woolley
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Electrical Conductivity ◽  
Conduction Band ◽  
Room Temperature ◽  
Energy Gap ◽  
Band Model ◽  
Scattering Coefficients ◽  
Wide Range ◽  
Different Temperatures

Calculations have been made using the Fletcher and Butcher method in a three conduction band model to fit a wide range of experimental transport data for n-type samples of GaSb: viz. Hall coefficient and electrical conductivity as a function of temperature and as a function of pressure at room temperature, magnetoresistance as a function of magnetic field at different temperatures, and Nernst–Ettingshausen coefficients as a function of magnetic field. Various energy gap parameters and scattering coefficients have been taken as adjustable and values determined for these which give good fits to all of the experimental data. Values of mobility for each of the Γ, L, and X bands have then been calculated as a function of temperature.

Photoswitching of the Optical and Electrical Properties of One-dimensional π-Electron Systems

2002 ◽  
Vol 57 (1-2) ◽  
pp. 89-93
Author(s):  
Nikolai Tyutyulkov ◽  
Fritz Dietz
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Light Absorption ◽  
Energy Gap ◽  
Optical And Electrical Properties ◽  
Electron Systems ◽  
Elementary Unit ◽  
One Dimensional ◽  
Correlation Correction ◽  
Gap Width

The photoswitching of the energy gap width of the isomeric forms of photoresponsive polymers with homomiclear photochrome diaryletheue elementary units is investigated theoretically, taking into account the correlation correction. It is shown that a real switching of electrical conductivity (insulator ⇔ semiconductor or conductor) can not be realized with polymers with alternant homomiclear π -electron systems within the elementary unit. A change and tuning-in of the light absorption is possible in most cases.

scholarly journals Studies on Surface Morphology and Electrical Conductivity of PS Thin Films in Presence of Divalent Complexes

2019 ◽  
Vol 16 (3) ◽  
pp. 0588 ◽  
Author(s):  
Al-Taa'y Et al.
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Refractive Index ◽  
Surface Morphology ◽  
Structural Modification ◽  
Energy Gap ◽  
Three Dimensional ◽  
Optical Parameters ◽  
Optical Energy Gap ◽  
Energy Gaps

       Optical properties and surface morphology of pure and doped Polystyrene films with different divalent metals of Zn, Cu and Sn and one concentration percentage have been studied. Measurements of UV-Vis spectrophotometer and AFM spectroscopy were determined. The absorbance, transmittance and reflectance spectrums were used to study different optical parameters such as absorption coefficient, refractive index, extinction coefficient and energy gap in the wavelengths rang 200-800nm. These parameters have increased in the presence of the metals. The change in the calculated values of energy gaps with doping metals content has been investigated in terms of PS matrix structural modification. The value of optical energy gap was found decreasing from 4.5eV of pure PS to reach 4.45, 4.38 and 4.32eV for Zn, Cu and Sn respectively. Measurement by AFM spectroscopy was done for two and three dimensional topographic images. From figures, the data of roughness average were 7.29, 7.31, 3.37 and 6.73nm for samples (Blank, Zn, Cu and Sn) respectively.

scholarly journals Measurements of the Electrical Conductivity of Monolayer Graphene Flakes Using Conductive Atomic Force Microscopy

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2575
Author(s):  
Soomook Lim ◽  
Hyunsoo Park ◽  
Go Yamamoto ◽  
Changgu Lee ◽  
Ji Won Suk
Keyword(s):  
Electrical Conductivity ◽  
Atomic Force Microscopy ◽  
Graphene Oxide ◽  
Monolayer Graphene ◽  
Synthesis Methods ◽  
Clear Understanding ◽  
Conductive Atomic Force Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Graphene Flakes

The intrinsic electrical conductivity of graphene is one of the key factors affecting the electrical conductance of its assemblies, such as papers, films, powders, and composites. Here, the local electrical conductivity of the individual graphene flakes was investigated using conductive atomic force microscopy (C-AFM). An isolated graphene flake connected to a pre-fabricated electrode was scanned using an electrically biased tip, which generated a current map over the flake area. The current change as a function of the distance between the tip and the electrode was analyzed analytically to estimate the contact resistance as well as the local conductivity of the flake. This method was applied to characterize graphene materials obtained using two representative large-scale synthesis methods. Monolayer graphene flakes synthesized by chemical vapor deposition on copper exhibited an electrical conductivity of 1.46 ± 0.82 × 106 S/m. Reduced graphene oxide (rGO) flakes obtained by thermal annealing of graphene oxide at 300 and 600 °C exhibited electrical conductivities of 2.3 ± 1.0 and 14.6 ± 5.5 S/m, respectively, showing the effect of thermal reduction on the electrical conductivity of rGO flakes. This study demonstrates an alternative method to characterizing the intrinsic electrical conductivity of graphene-based materials, which affords a clear understanding of the local properties of individual graphene flakes.

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