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![Current density (filled symbols) and luminance (open symbols) versus applied forward bias for an OLED on graphene (squares) and ITO (circles) [135]](profile/Mohammadreza-Kolahdouz/publication/272401230/figure/fig20/AS:614212061650973@1523450975285/Current-density-filled-symbols-and-luminance-open-symbols-versus-applied-forward-bias.png)
Current density (filled symbols) and luminance (open symbols) versus applied forward bias for an OLED on graphene (squares) and ITO (circles) [135]
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![Fig. 1 sp 2 hybrids of each carbon atom in graphene [185]](profile/Mohammadreza-Kolahdouz/publication/272401230/figure/fig1/AS:614212057432108@1523450974635/sp-2-hybrids-of-each-carbon-atom-in-graphene-185_Q320.jpg)
In the last decade, as semiconductor industry was approaching the end of the exponential Moore’s roadmap for device downscaling, the necessity of finding new candidate materials has forced many research groups to explore many different types of non-conventional materials. Among them, graphene, CNTs and organic conductors are the most successful alt...
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... Traditional methods for detecting DA include blood tests and 24 h urine sampling. Usually, these methods require specialized technical training and laboratory equipment, including high-performance liquid chromatography, fluorescence spectroscopy, enzyme analysis, mass spectrometry, and capillary electrophoresis, which are greatly limited due to the high cost and operationally complex [10][11][12][13][14]. Recently, electrochemical sensing methods developed fast, offering advantages such as simplicity, low cost, ease of use, ...
This article reports a simple hydrothermal method for synthesizing nickel disulfide (NiS2) on the surface of fluorine-doped tin oxide (FTO) glass, followed by the deposition of 5 nm Au nanoparticles on the electrode surface by physical vapor deposition. This process ensures the uniform distribution of Au nanoparticles on the NiS2 surface to enhance its conductivity. Finally, an Au@NiS2-FTO electrochemical biosensor is obtained for the detection of dopamine (DA). The composite material is characterized using transmission electron microscopy (TEM), UV-Vis spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical properties of the sensor are investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and time current curves in a 0.1 M PBS solution (pH = 7.3). In the detection of DA, Au@NiS2-FTO exhibits a wide linear detection range (0.1~1000 μM), low detection limit (1 nM), and fast response time (0.1 s). After the addition of interfering substances, such as glucose, L-ascorbic acid, uric acid, CaCl2, NaCl, and KCl, the electrode potential remains relatively unchanged, demonstrating its strong anti-interference capability. It also demonstrates strong sensitivity and reproducibility. The obtained Au@NiS2-FTO provides a simple and easy-to-operate example for constructing nanometer catalysts with enzyme-like properties. These results provide a promising method utilizing Au coating to enhance the conductivity of transition metal sulfides.
... Raman spectra of pure GO and with 4, 15, and 30 wt. % Al 2 O 3 are also exhibited in Fig. 4(a), showing four major characteristic peaks such as D, G, 2D, and D + G. 21 The D-peak at 1359 cm −1 originated from the A 1g breathing modes of six-atom rings in the presence of defects/disorders 29 via double resonance mediated activation of the TO phonons around the K point of the BZ. [30][31][32] However, the G-peak stands for the first-order Raman scattering associated with the E 2g vibrational mode of sp 2 bonds 30 and it is observed at ∼1603 cm −1 for GO. The 2D-peak, on the other hand, is the second-order D-peak, but no defects are required for activating this band. ...
As water pollution is increasing due to industrialization, there is a high demand for easy-processing photocatalytic materials to clean wastewater. Here, the improvement in the photocatalytic dye degradation effect of graphene oxide (GO) surfaces, made of ultra-sonication assisted modified Hummer's method, is demonstrated with increasing alumina (Al2O3) concentration in the range of 4–30 wt. %. Scanning electron microscopy and x-ray diffraction results suggest a gradual increment in crystalline Al2O3 nanoparticles (NPs) by reducing GO, in good agreement with the first-principles calculations. Moreover, x-ray photoelectron spectroscopy reveals the appearance of oxygenated functional groups with increasing Al2O3 concentration, leading to the formation of defect-rich GO as demonstrated by Raman spectroscopy. Ultraviolet-visible spectroscopy further reflects a maximum reduction in the optical bandgap from 1.88 to 1.56 eV up to a concentration of 15 wt. % Al2O3. Interestingly, the methylene blue degradation efficiency of GO under ultraviolet irradiation is also found to be improved from 45% to 64% with 15 wt. % Al2O3, whereas the formation of Al2O3 NPs in the range of 100–300 nm with 30 wt. % Al2O3 is found to be detrimental for photocatalytic activity.
... A hydrogel-based [17] photodetection device [18] was used in a different investigation. A graphene sheet [19][20][21][22][23] produced by CVD [24] was also used to examine the photodetection [25][26][27]. Additionally, the electrochemical approach [14] is used to create the porous structure since it is simple to use and affordable [28]. ...
Silicon (Si); the most abundant raw material on the earth’s crust upholds a promising future in the silicon or electronic industry. However, the intrinsic indirect bandgap (1.12 eV), limits its usage in optoelectronics devices due to the passage of the infrared spectrum. Herein, we have structurally modified the Si structure into a nanostructured material like porous silicon (PS) for application in optoelectronic devices. In order to make PS structures, n-type monocrystalline Si was anodized in an ethanoic-HF solution. The average diameter of the pores created by anisotropic electrochemical etching with fixed time and current density was determined to be around 250 nm. The PS demonstrated a direct bandgap and an energy gap of 1.73 eV. The obtained PS-based device's photoresponse (PR) was investigated at various laser irradiation wavelengths. The best response sensitivity of 11.18% was noted at a wavelength of 786 nm, thus, promising to be a potential material for visible range photodetectors.
... Graphene (Gr) is one of the well-known 2D nanomaterials that can manipulate the electrical properties of LCs 22,23,[32][33][34][24][25][26][27][28][29][30][31] . The effectiveness of Gr layers in different phases of LCs often leads to two outcomes: (I) When Gr sheets mix with LC, their electrostatic eld leads to the suppression of ionic behaviors such as reduction in ionic density, diffusivity, and relaxation frequency through the ion trapping/charge annihilation process 21 ; (II) The interaction between the honeycomb pattern of Gr and the benzene rings of LC molecules causes the LC directors to planar stabilize on the surface of the Gr layers and results in the improvement of dielectric anisotropy 35 . ...
Enhancing the ionic conductivity of liquid crystal (LC) circumvents challenges for application in advanced electronic components. Toward this, using additives made of different nanostructures that could result in functional LCs is suggested. In this paper, various concentrations of graphene (Gr)/metal-oxide (Fe 3 O 4 ) nanocomposite (GMN) (0.0001-1 w%) were added to E7 nematic LC. We found that the role of anisotropic Gr flakes, their edges as well as surface-decorated-metal-oxide-additives have significant impact on electrical properties of E7. A range of appropriate additives of such a nanocomposite enhances the electrical conductivity of LCs. This effect can be traced through the decrease in the formation of GMN aggregates in the E7 and increase in the electrostatic field at the edges of the Gr sheets. Moreover, the presence of metal-oxide nanoclusters due to the presence of oxygen vacancies and defects facilitates the construction of conductive network for improving the charge transfer pathways and contributes to a stronger interaction of the Gr surface with charged species. These factors can provide Gr layers as dipole moments and lead to signal propagation in the dielectric medium. Our finding conveys a pathway toward significant enhancement of ionic conductivity in the LC family which can be useful for functional applications.
... However, for large-area applications, CVD techniques are more favorable. CVD methods such as thermal CVD and plasma-enhanced CVD (PECVD) are unique because of producing uniform layer of thermally-chemically catalyzed carbon atoms that can be deposited onto metal surfaces and also can be transferred over a wide range of substrates [82]. But the C/ H ratio, substrate quality, temperature, pressure and oxygen on the substrate surface also affect the process of graphene synthesis when using the CVD methods [83]. ...
Nowadays, cancer is increasingly becoming one of the foremost threats to human being life worldwide, and diagnosing this deadly disease is one of the major priorities of researchers. Described as a monolayer-thin-sheet of hexagonally patterned carbon atoms, ‘graphene’ is considered an innovative evergreen carbon material ideal for a wide array of sensing applications and nanotechnologies. Graphene-based materials have acquired a huge share of interest in the scope of biosensor fabrication for early and accurate cancer diagnosis. Herein, we have insights reviewed the various routes and technologies for synthesized graphene, and graphene-based materials including 3D graphene (i.e., hydrogels, foams, sponges, porous), and 0D graphene (i.e., quantum dots). Moreover, we have introduced the different types of graphene/graphene-based materials biosensors (i.e., electrochemical biosensors, optical biosensors, field-effect transistors biosensors, electrochemiluminescence biosensors, and microfluidics biosensors) and their merits and applications for cancer pre-stage detection.
... However, for large-area applications, CVD techniques are more favourable. CVD methods such as thermal CVD and plasma-enhanced CVD (PECVD) are unique because of producing uniform layer of thermally-chemically catalyzed carbon atoms that can be deposited onto metal surfaces and also can be transferred over a wide range of substrates [82]. But the C/H ratio, substrate quality, temperature, pressure, and oxygen on the substrate surface also affects the process of graphene synthesis when using the CVD methods [83]. ...
Nowadays, cancer is increasingly becoming one of the foremost threats to human being life worldwide, and diagnosing this deadly disease is one of the major priorities of researchers. Described as a monolayer-thin-sheet of hexagonally patterned carbon atoms, 'graphene' is considered an innovative evergreen carbon material ideal for a wide array of sensing applications and nanotechnologies. Graphene-based materials have acquired a huge share of interest in the scope of biosensor fabrication for early and accurate cancer diagnosis. Herein, we have insights reviewed the various routes and technologies for synthesized graphene, and graphene-based materials including 3D graphene (i.e., hydrogels, foams, sponges, porous), and 0D graphene (i.e., quantum dots). Moreover, we have introduced the different types of graphene/graphene-based materials biosensors (i.e., electrochemical biosensors, optical biosensors, field-effect transistors biosensors, electrochemiluminescence biosensors, and microfluidics biosensors) and their merits and applications for cancer pre-stage detection.
... in order to enhance the efficiency such as the use of antireflection coating on low-temperature-grown gallium arsenide (LT-GaAs) [8], AlAs-AlGaAs based Bragg reflector under the LT-GaAs layer [9], nano-plasmonic structures [10], nanoplasmonic double layer structure [11], recessed electrode and recessed nano-plasmonic array, nano-spaced electrodes [12], graphene [13], plasmonic nanostructure [14], and optical plasmonic nano-antenna [15]. ...
The interaction of femtosecond laser pulses with thin solid targets is one of the most efficient methods to obtain terahertz (THz) radiation. In the specific conditions, the electron of plasma surface distribution became so localized and nano-bunches are formed which causes coherent synchrotron emission (CSE). In this mechanism which occurs when the relativistic laser is obliquely incident on plasma, the plasma electrons gather in a very dense and thin layer of nanometer width. The electrons of nano-bunch can emit intense coherent emissions in different ranges of electromagnetic radiation. In this study, producing high-efficiency THz radiating from relativistic nano-bunches is discussed. The effect of plasma and nano-bunch parameters, the mobility of ions, the initial thermal velocity of electrons, and the speed of electrons are investigated. According to the results, the direct relation between the width of the nano-bunch and the efficiency is seen. The nonlinear relation between the initial thermal velocity of electrons and the THz yield is seen. In the desirable conditions, a high THz yield of up to 37% is obtained from nano-bunches with the initial thermal velocities as 0.3 of light speed.
... Carbon, as the most versatile element with diverse forms of bonding, can produce many structures, such as 0D, 1D, 2D and 3D. Carbon with sp 2 hybridization can form a hexagonal-shaped lattice typical of a sheet of graphite, while carbon with sp 3 hybridization can construct the most complex 3D crystalline structure in diamond [15]. Fullerene, carbon nanotubes and graphene are examples of 0D, 1D and 2D structures, respectively. ...
... [36]. (b) sp 2 hybrids of carbon atom connecting with neighboring ones in graphene [15]. [36]. ...
... [36]. (b) sp 2 hybrids of carbon atom connecting with neighboring ones in graphene [15]. ...
As the scaling technology in the silicon-based semiconductor industry is approaching physical limits, it is necessary to search for proper materials to be utilized as alternatives for nanoscale devices and technologies. On the other hand, carbon-related nanomaterials have attracted so much attention from a vast variety of research and industry groups due to the outstanding electrical, optical, mechanical and thermal characteristics. Such materials have been used in a variety of devices in microelectronics. In particular, graphene and carbon nanotubes are extraordinarily favorable substances in the literature. Hence, investigation of carbon-related nanomaterials and nanostructures in different ranges of applications in science, technology and engineering is mandatory. This paper reviews the basics, advantages, drawbacks and investigates the recent progress and advances of such materials in micro and nanoelectronics, optoelectronics and biotechnology.
... Carbon-based materials (CBM), such as graphene, fullerene, carbon nanotubes, diamond-like carbons (DLC), amorphous carbons, etc., typically exhibit exceptional properties [28,[31][32][33][34]. For example, graphene has been found to be durable, shock-resistant, and has good electrical characteristics [35]. However, it is expensive, and furthermore it is difficult to grow graphene-based thin films on a large scale. ...
Diamond-like carbon films have found various areas of application due to their particularly durable characteristics. To enhance the electrical and optoelectronic characteristics of the material, diamond-like carbon was co-deposited with Ge on p-type Si wafer using the DC magnetron sputtering technique, from which diamond-like carbon-germanium nanocomposites were obtained. The structural properties of the nanocomposites were assessed using electron microscopy techniques. The chemical structure of the nanocomposite films was confirmed using energy dispersive spectroscopy and Raman spectroscopy. The electrical properties of the nanocomposite films were investigated via various electrical parameters as determined through current-voltage, capacitance–voltage, and conductance–voltage graphs. Photoresponsive and photosensitivity properties were also assessed using a solar simulator at various illumination intensities. It was concluded that nanocomposite thin films were responsive to light, where photosensitivity and photoresponsivity increased with increasing illumination intensity. The electrical characteristics of the nanocomposite films were associated with the frequency of the AC voltage applied.
... However, there is the issue of low optical-to-THz conversion efficiency [3,4]. Efforts have been made to enhance the efficiency by improving the laser pulse coupling, including the use of anti-reflection coating on Low-Temperature-grown Gallium Arsenide (LT-GaAs) [5], AlAs-AlGaAs based Bragg reflector under the LT-GaAs layer [6], nanoplasmonic structures [7], nanoplasmonic double layer structure [8,9], recessed electrode and recessed nanoplasmonic array, nano-spaced electrodes [10], optical plasmonic nano-antenna [11], plasmonic nanostructure [12], graphene [13]. ...
... The THz radiated power can be calculated in Eq. (13). ...
... The IPCA teeth width of 100 nm possess conductance of 0.15048 ℧ whereas the conventional dipole PCA possess 0.000173 ℧ with 250 mW input optical power. To calculate THz radiation power of an IPCA, the antenna radiation resistance is required based on Eq. (13). Hence, the IPCA can be designed using the Finite Element Method (FEM) within Ansys High-Frequency Structure Simulator (HFSS) package. ...
THz signals can be generated commonly from Photoconductive Antenna (PCA) but the efficiency is low for the conventional PCA. This work improves the optical to terahertz conversion efficiency of the terahertz radiation by changing the conventional PCA structure to Interdigitated PCA (IPCA). The efficiency of PCA is dependent on the current pulse generated in the antenna structure when the laser pulse is incident on it. This paper targets to achieve high photo-current, as well as THz electric field from the IPCAs which are simulated using FEM and FDTD techniques. Also, the effect of various parameters such as current, gain, frequency bandwidth, optical to terahertz conversion efficiency, etc. are studied to study the importance of IPCAs.
