International Journal of Nanoscience

In this paper, we introduce a model to analyze the manufacturing of an implanted-junction rectifier. The model gives a possibility to analyze dependence of charge carriers mobility on the value of dose of implanted ions. Also, we introduce an analytical approach to analyze mass transfer. The approach gives a possibility to make the analysis in a more common situation, as was recently done in the literature. Analysis of the introduced model shows an increae in the spread of distribution of dopant and decrease of mismatch-induced stresses in multilayer structures with increase of dose of implanted ions.

This paper presents the direct growth of vertical graphene (VG) using a metal shield (MS)-assisted plasma-enhanced chemical vapor deposition (PECVD) method. The 300 $W_{\text{RF}}$ Ar/CH₄ plasma is used to grow VG at 600^∘C for 30 min on a 200 mm Si wafer. Without MS, the high Ar⁺ physical and H⁺ chemical rate etching of plasma prevents the growth of VG. The installation of 1 MS helps reduce the etching by reducing the ions density in the lower plasma zone and allows localized growth of VG as dark spots on the Si wafer. The crystal quality of VG grown by Ar/CH₄ plasma with 1 MS is satisfyingly good with a narrow Raman I(G) peak within 36–40 cm⁻¹, and the thickness of individual VG leaf is few-layer graphene since I(2D)$∕I$(G) is $\sim 1$. The installation of 2 MS further improves the coverage, size, and population density of VG on the Si wafer by further lowering the ions density in the lower plasma zone. Further annealing of VG at 1040^∘C in an Ar/H₂/CH₄ environment can repair the carbon sp² but it is almost not required as the hydrogen atoms can etch the VG and reduce its coverage on a 200 mm Si wafer.

Power consumption and especially leakage power are the main concerns of nano MOSFET technology. On the other hand, binary circuits face a huge number of interconnection wires, which results in power dissipation and area. Researchers introduced emerging nanodevices and multiple-valued logic (MVL) as two feasible solutions to overcome the challenges mentioned above. Carbon nanotube field-effect transistor (CNFET) is one of the emerging technologies that has some unique properties and advantages over MOSFET, such as adjusting the carbon nanotube (CNT) diameters to have the desired threshold voltage and have the same mobility as P-FET and N-FET transistors. In this paper, we present a novel method for designing ternary logic circuits based on CNFETs. Each of our designed logic circuits implements a logic function and its complementary via a control signal. Also, these circuits have a high impedance state, which saves power while the circuits are not in use. Moreover, we designed a two-digit adder/ subtractor and a power-efficient ternary logic arithmetic logic unit (ALU) based on the proposed gates. The proposed ternary circuits are simulated using HSPICE via standard 32 nm CNFET technology. The simulation results indicate the designs’ correct operation under different process, voltage, and temperature (PVT) variations. Also, simulation results show that the two-digit adder/ subtractor using our proposed gates has 12X and 5X lower power consumption and power-delay product (PDP), respectively, compared to previous designs.

The nanocomposite was created in order to investigate field emission (FE) applications. A MWCNTs/ZnO nanocomposite, by combining ZnO thin films with multi-wall carbon nanotubes (MWCNTs), was synthesized by the use of chemical vapor deposition (CVD) techniques for FE applications. The thin films were then prepared by dip-coating and drop-casting onto a silicon substrate. The field emission scanning electron microscopy (FESEM), Raman spectroscopy and the X-ray diffraction (XRD) techniques were used to characterize the MWCNTs and MWCNTs/ZnO nanocomposite separately and compare the results. From Raman spectra, the calculated values of ID/IG are, respectively, 0.521 and 0.950, which confirm the certain defects and disorders produced after coating of ZnO nanoparticles on the MWCNTs’ surface. From the current density–electric field plot, it is found that the FE properties increased by three times which indicates that MWCNTs/ZnO nanocomposite can be useful for ideal cathode emitters.

In this paper, we report herein for the first time that a stop solution should be used to terminate the metal nanoparticles (MNPs) aggregation reactions especially salt-induced ones to increase the repeatability of the assays. It was found that hydrophobic surfactants have the ability to slow down the aggregation process of MNPs and can be applied as stop solution for aggregation-based colorimetric assays. This trick provides accurate and well-repeatable signals since the aggregation of the nanoparticles is a dynamic process and capturing signal in a predetermined time is difficult.

Green synthesis of nanoparticles is rapidly evolving because it is cost-effective and eco-friendly, this also contributes to its preference over nanoparticles from other sources. In this study, silver nanoparticles were synthesized from Allium cepa (AC) and Raphanus sativus (RS) aqueous extracts and the biological activities were evaluated. The silver nanoparticles AgNPs@AC and AgNPS@RS were synthesized from AC and RS extracts, respectively, using silver nitrate and characterized using UV–visible spectroscopy (UV–Vis), Fourier transform infrared (FT-IR) spectroscopy, Powder X-ray diffraction (PXRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). The FT-IR spectra of AgNPs@AC and AgNPS@RS showed characteristic groups pertaining to active molecules of the respective extracts indicating their surface functionalization. The XRD pattern of AgNPs@AC revealed diffraction peaks at 38.26, 44.39, 64.65, 77.54 and 81.64 that were indexed to (1 1 1), (2 0 0), (2 2 0), (3 1 1) and (2 2 2) planes of face-centered cubic (FCC) crystalline structure, respectively. The XRD pattern of AgNPs@RS revealed diffraction peaks at 38.24, 44.32, 64.62, 77.46 and 81.65 that was indexed to (1 1 1), (2 0 0), (2 2 0), (3 1 1) and (2 2 2) planes of face-centered cubic (FCC) crystalline structure, respectively. The SEM images indicate that the particles are spherical in shape and have particle size in the range of 25–35 nm. The nanoparticles demonstrated substantial antimicrobial activity against Gram +ve and Gram −ve harmful bacteria species, such as S. aureus, E. coli and fungal species C. albicans. This study shows that A. cepa (Onion) and R. sativus (Radish) aqueous extracts can be used as an effective reducing and capping agent for the green synthesis of silver nanoparticles (AgNP). AgNPS@RS showed acceptable size and shape of nanoparticles and could therefore be a potential source of antimicrobial agents.

The laser-generated plasma was characterized using laser-induced breakdown spectroscopy after fundamental radiation from a Nd:YAG laser with an energy range of 300–500 mJ was focused onto a magnesium target. Using magnesium emission lines and Boltzmann plots, the plasma parameters were computed based on experimental data. The plasma electron temperature varied between (2.36–3.12) eV as a function of laser energy, while the density of electrons varied between (1.02–1.49$)\times 10^{18}$ cm³ at ($\lambda =1064$ nm). These values grew as laser irradiation increased, albeit at varied rates depending on the wavelength.

The structural, morphology, and optical properties of a new hybrid structure prepared from CuO nanoparticles embedded in a Fe₂O₃–PVA composite matrix were investigated in this work. Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), absorption and transmission spectra, and Fourier transform infrared spectroscopy (FT-IR) were all used to analyze the prepared materials. Crystallography information revealed the presence of CuO that did not affect the crystal structure of PVA–Fe₂O₃. The prepared composites revealed strong absorption in the range of 440–570 nm. It was observed that the highest absorption of these composites gradually shifted to the shorter wavelength region with the presence of CuO. PVA–Fe₂O₃ is highly transparent, with a transmittance of around 85% in the range of 600–800 nm. After the addition of 5% by weight of CuO nanoparticles, the transmittance of the nanocomposite drops to 75% in the same range of wavelength. The prepared materials were used as anti-cancer cells, and they showed high efficacy to kill tumor cells, especially PVA–Fe₂O₃–CuO at concentration 0.5 $\mu$g/mL.

In the present work, Cadmium sulfide (CdS) and CdS doped with copper (Cu) and iron (Fe) metals thin films were deposited on glass slides using chemical bath deposition technique. 1% content of Cu and Fe were used as dopants. The films were prepared at a reaction temperature of approximately 80^∘C and for an hour as the reaction time without any heat treatment. The pure and doped films were diagnosed and examined by several techniques such as X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and UV-visible spectrometry to study the effect of the doping and the type of dopant material on the surface, structural and optical properties of CdS films. From the results of XRD can be noticed there is no effect for the dopant on the type of crystal structure except small shifting in the position of main peak after doping. The bandgap energy of the Fe-doped CdS films has been found to be lower than that of the undoped films between 2.62 eV and 2.43 eV.

We report on the fabrication of zinc oxide (ZnO) nanorod-based flexible, cost-effective single electrode triboelectric nanogenerator (STENG) on cellulose paper platform. In particular, the influence of surface functional groups of ZnO nanorods on the STENG output has been investigated. The STENG has been designed with chemically grown ZnO nanorod-coated paper as active triboelectric layer and Teflon/ Aluminum as counter triboelectric layer/ electrode. It has been found that post-annealing of nanorods at 125^∘C improves the output voltage by twice compared to the pristine nanorods and delivers an output power of $\sim 0.2\mu$W/cm². With annealing up to 125^∘C, the optimal removal of the chemisorbed water from the defect sites of ZnO surface increases the intrinsic carrier concentration leading to maximum charge transfer and hence higher triboelectric output. On the other hand, a higher extent of oxygen accumulation from air at 150^∘C lowers the intrinsic carrier concentration resulting in the reduced output. It has been proposed that the competition between the events like water removal and oxygen accumulation under different annealing temperatures can influence the STENG output largely. Finally, the optimized STENG has been demonstrated to work as wearable bio-mechanical sensors operating through bio-mechanical stimuli.