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Driven conductance of an irradiated semi-Dirac material
摘要： We theoretically investigate the electronic and transport properties of a semi-Dirac material under the influence of an external time-dependent periodic driving field (irradiation) by means of Floquet theory. We explore the inelastic scattering mechanism between different sidebands, induced by irradiation, by using the Floquet scattering matrix approach. The scattering probabilities between the two nearest sidebands depend monotonically on the strength of the amplitude of the irradiation. The external irradiation induces a gap in the band dispersion which is strongly dependent on the angular orientation of momentum. Although the high-frequency limit indicates that the gap opening does not occur in an irradiated semi-Dirac material, a careful analysis of the full band structure beyond this limit reveals that a gap opening indeed appears for higher values of momentum (away from the Dirac point). Furthermore, the angular-dependent dynamical gap is also present and cannot be captured within the high-frequency approximation. The contrasting features of an irradiated semi-Dirac material, in comparison with irradiated graphene, can be probed via the behavior of conductance. The latter exhibits the appearance of nonzero conductance dips due to the gap opening in the Floquet band spectrum. Moreover, by considering a nanoribbon geometry of such a material, we also show that it can host a pair of edge modes which are fully decoupled from the bulk, which is in contrast to the case of a graphene nanoribbon where the edge modes are coupled to the bulk. We also investigate whether, if the nanoribbon of this material is exposed to the external irradiation, decoupled edge modes penetrate into the bulk.
关键词： Floquet theory,edge modes,semi-Dirac material,conductance,irradiation
更新于2025-09-04 15:30:14
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Characteristics of Graphene Oxide Films Reduced by Using an Atmospheric Plasma System
摘要： The chemical oxidation method can be used to mass-produce graphene oxides (GOs) from highly oriented pyrolytic graphite. However, numerous oxygen-containing functional groups (hydroxyl, epoxy, carbonyl, etc.) exist in typical GO surfaces, resulting in serious electrical losses. Hence, GO must be processed into reduced graphene oxide (rGO) by the removal of most of the oxygen-containing functional groups. This research concentrates on the reduction efficiency of GO films that are manufactured using atmospheric-pressure and continuous plasma irradiation. Before and after sessions of plasma irradiation with various irradiation times, shelters, and working distances, the surface, physical, and electrical characteristics of homemade GO and rGO films are measured and analyzed. Experimental results showed that the sheet resistance values of rGO films with silicon or quartz shelters were markedly lower than those of GO films because the rGO films were mostly deprived of oxygen-containing functional groups. The lowest sheet resistance value and the largest carbon-to-oxygen ratio of typical rGO films were approximately 90 ?/sq and 1.522, respectively. The intensity of the C–O bond peak in typical rGO films was significantly lower than that in GO films. Moreover, the intensity of the C–C bond peak in typical rGO films was considerably higher than that in GO films.
关键词： sheet resistance,oxygen functional group,GO and rGO films,plasma irradiation,carbon-to-oxygen ratio
更新于2025-09-04 15:30:14
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Antibacterial and photocatalytic activity of hydrothermally synthesized SnO2 doped GO and CNT under visible light irradiation
摘要： Bacterial and dye pollution are major problems with wastewater treatment. An increasing number of photocatalysts are being used in industry to kill bacterial and reduce pollution. In the present study, highly stable SnO2-doped nanocomposites have been prepared successively by a hydrothermal method. The synthesized nanocomposite was characterized using a range of techniques, such as X-ray diffraction, field emission scanning electron microscopy with energy dispersive X-ray spectroscopy and electron probe micro analysis, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, and high resolution transmission electron microscopy (HR-TEM). The nanocomposites showed significant dose-dependent bactericidal activity in the disc diffusion assay and cell viability test. The S-GO-SnO2 200 μg/mL produced a cell viability of 184.3 ± 11.71 and 172.3 ± 3.05 × 106 CFU/mL for E. coli and P. graminis, respectively. The S-GO-SnO2 showed significant photocatalytic degradation against MB in 120 min. The photocatalyst S-GO-SnO2 showed 159 and 161 × 106 CFU/mL at 150 min in E. coli and P. graminis, respectively. The cells treated with photocatalytic SnO2-doped nanocomposites showed 50% cell death. HR-TEM revealed 50% cell growth inhibition by bacterial damage. This photocatalytic SnO2-doped nanocomposite is a good candidate for treating industrial wastewater treatment contaminated with dyes and bacteria.
关键词： Antibacterial activity,Photocatalytic activity,Hydrothermal syntheses,Visible light irradiation,SGO-SnO2,SCNT-SnO2
更新于2025-09-04 15:30:14