Nanoscience & Nanotechnology-Asia - Volume 10, Issue 4, 2020

All optical tri-state frequency encoded logic gates NOT and NAND are proposed and numerically investigated using TOAD based interferometric switch for the first time to the best of our knowledge. The optical power spectrum, extinction ratio, contrast ration, and amplified spontaneous noise are calculated to analyze and confirm practical feasibility of the gates. The proposed device works for low switching energy and has high contrast and extinction ratio as indicated in this work.

Introduction: The objective of this study was to formulate water-insoluble drug Itraconazole (ITZ) into Solid Lipid Nanoparticles (SLNs) for topical delivery. Methods: The drug-loaded SLNs were prepared by Microemulsion method using cholesterol (CH) and Lubritab (LU) and further characterized for different parameters like particle size, zeta potential, drug entrapment efficiency etc. The mean particle size with Lubritab SLN was in the range 155.01-161.67 nm, whereas for Cholestrol SLN it was in the range of 218.87-230.16 nm. SEM showed spherical nature of the SLNs. Results: The entrapment efficiency of SLN was found to be more for cholesterol as compared to Lubritab. The crystalline properties of drug was reduced in SLNs as evaluated by X-ray diffraction (XRD). Ex vivo study indicated the ITZ-SLN exhibited high concentration. Conclusion: The permeability of drug was studied by use of Franz-diffusion cell, and permeation of drug through Lubritab SLN (ITZ LU) was higher than that of Cholesterol SLN (ITZ CH). The formulated ITZ-SLNs exhibited clear zone.

Objective: The objective of the present studies was to develop and evaluate curcumin loaded NLCs for management of childhood dermatitis by exploiting its antimicrobial and anti-infective properties and increasing its skin deposition. Methods: The screened lipidic excipients (on solubility basis) were used to formulate NLC dispersion by solvent injection technique and process variables were optimized. Central composite design was employed to study the effect of surfactant, total lipid and ratio of solid lipid to liquid lipid on dependent variables such as particle size, zeta potential, % entrapment efficiency and time for 80% drug release. Curcumin NLCs were incorporated into carbopol 934 P based gel and characterized for morphological and rheological properties, drug release, skin permeation and retention study, skin irritancy, in vitro microbial activity and stability. Results: The optimized formulations exhibited satisfactory physicochemical properties and followed Higuchi kinetic model. The NLC dispersion when incorporated into gel, was stable and nonirritating. Antimicrobial study against S. aureus showed larger zone of inhibition with developed formulation. Statistical model indicated that higher surfactant concentrations, lower lipid concentrations, reducing the solid lipid content minimized the particle size, maximized the % entrapment efficiency and optimized time for 80% drug release, while it had an inverse effect on zeta potential. The TEM of NLC dispersions elucidated its sphericity. Conclusion: The developed curcumin NLC gel exhibited potential in management of childhood dermatitis by virtue of sustained drug release, increase skin deposition and efficient antimicrobial action.

Background: The objective of this study was to develop solid lipid nanoparticles (SLNs) of poorly water soluble anti-hyperlipidemic drugs-Ezetimibe in combination with Simvastatin. Methods: This study describes a 32 full factorial experimental design to optimize the formulation of drug loaded lipid nanoparticles (SLN) by the high speed homogenization technique. The independent variables amount of lipid (GMS) and amount of surfactant (Poloxamer 188) were studied at three levels and arranged in a 32 factorial design to study the influence on the response variables- particle size, % entrapment efficiency (%EE) and cumulative drug release (% CDR) at 24 h. Results: The particle size, % EE and % CDR at 24 h for the 9 batches (B1 to B9) showed a wide variation of 104.6-496.6 nm, 47.80-82.05% (Simvastatin); 48.60-84.23% (Ezetimibe) and 54.64-92.27% (Simvastatin); 43.8-97.1% (Ezetimibe), respectively. The responses of the design were analysed using Design Expert 10.0.2. (Stat-Ease, Inc, USA), and the analytical tools of software were used to draw response surface plots. From the statistical analysis of data, polynomial equations were generated. Optimized formulation showed particle size of 169.5 nm, % EE of 75.43% (Simvastatin); 79.10% (Ezetimibe) and 74.13% (Simvastatin); 77.11% (Ezetimibe) %CDR after 24 h. Thermal analysis of prepared solid lipid nanoparticles gave indication of solubilisation of drugs within lipid matrix. Conclusion: Fourier Transformation Infrared Spectroscopy (FTIR) showed the absence of new bands for loaded solid lipid nanoparticles indicating no interaction between drugs and lipid matrix and being only dissolved in it. Electron microscope of transmission techniques indicated sphere form of prepared solid lipid nanoparticles with smooth surface with size approximately around 100 nm.

Objective: In this proposed work, the Analog, RF and Linearity performances of a DGMOSFET have been analyzed by considering InAs as a channel material. Methods: For the very first time, gate stack techniques in this device have been incorporated and a comparative analysis is conducted with respect to SiO2 oxide layer. The variations in different patterns of oxide layer and their comparison have been thoroughly investigated to have a better understanding of various performance parameters. A thorough analysis of the key figure-of-merits such as trans-conductance factor, transconductance generation factor (TGF), gate capacitance, cutoff frequency (fT), maximum frequency of oscillation (fmax), GBW and various linearity parameters such as gm2, gm3,VIP2, VIP3, IIP3, has been studied with respect to SiO2 oxide material and gate stack technology. Result: The simulation results revealed that the performances of the device are sensitive to both the oxide materials and it was also inferred that gate stack technology gave a better performance over SiO2 oxide layer. Conclusion: These results have significant effects in analog, RF and linearity operations. In this work, computer aided design (TCAD) simulations by 2D ATLAS, Silvaco International have been used.

Background: In this article, photonic extinction performance of Metal Dielectric Semiconductor (MDS) nanostructure has been improved by noble metallic nanosphere such as gold, silver and copper into various wideband dielectrics like silicon di-oxide, aluminum oxide and silicon nitride. Methods: Presently, Plasmonics gives very much interest and closely involves in the main domains of nanophotonics that can control of optical fields at the nanoscale level as well as it can concentrate and enhance the electromagnetic field on the nanometer scale especially in metal dielectric semiconductor (MDS) nanostructure. Results: In plasmonics, noble metals used as nanoparticle where density of electron gas which oscillates at surface Plasmon frequency so we investigate impact of various wideband dielectrics with nanoparticle size for enhancement of extinction in terms of absorption and scattering by using surface Plasmon resonance. Conclusion: At Plasmonic resonance the efficiency will be maximum. If the size of the metallic nanosphere increases, initially the efficiency increases up to a certain wavelength then it becomes sharply decreased.

Background: The stringent technological constraints imposed by the requirement of ultra-sharp doping profiles associated with the sub-30 nm regime has led to the search for alternatives to the conventional Metal Oxide Semiconductor (MOS) Field Effect Transistor (FET). An obvious alternative is a device whose architecture does not have any junctions in the sourcechannel- drain path. One such device is the Junctionless transistor comprising of an isolated ultrathin highly doped semiconductor layer whose volume is fully depleted in the OFF state and is around flat- band in the ON state. Such a structure overcomes the stringent technological requirement of an ultra-sharp grading profile required for nano-scale MOSFETs. For widespread application in today’s high-speed circuits, a key factor would be its effectiveness as a switch. Methods: In this work we have studied the relative sensitivity of two such parameters namely the ION/IOFF ratio and gate capacitance to variations in several structural parameters of the device namely channel width, composition of the dielectric layer, material composition of the channel region (i.e. Si vis-à-vis SiGe), doping concentration of the channel region and non-uniformity in the doping profile. Results: The work demonstrates through device simulations that replacement of Si with Si-Ge leads to an improvement in the performance. Conclusion: The most notable change has been observed by using a vertically graded doping profile as opposed to the original proposed uniformly doped channel.

Background: In nano and microelectronics, device performance enhancement is limited by downscaling. Introduction of intentional mechanical stress is a potential mobility booster to overcome these limitations. This paper explores the key design challenges of stress-engineered FinFETs based on the epitaxial SiGe S/D at 7 nm Technology node. Objective: To study the mechanical stress evolution in a tri-gate FinFET at 7 nm technology node using technology CAD (TCAD) simulations. Using stress maps, we analyze the mechanical stress impact on the transfer characteristics of the devices through device simulation. Methods: 3D sub-band Boltzmann transport analysis for tri-gate PMOS FinFETs was used, with 2D Schrödinger solution in the fin cross-section and 1D Boltzmann transport along the channel. Results: Using stress maps, the mechanical stress impact on the transfer characteristics of the device through device simulation has been analyzed. Conclusion: Suitability of predictive TCAD simulations to explore the potential of innovative strain-engineered FinFET structures for future generation CMOS technology is demonstrated.

Aims: In this work, a Junction-Less Double Gate MOSFET (JLDG MOSFET) based CMOS inverter circuit is proposed for ultra-low power applications in the near and sub-threshold regime operations. Background: D.C. performances like power, delay and voltage swing of the proposed Inverter have been modeled analytically and analyzed in depth. JLDG MOSFET has promising features to reduce the short-channel effects compared to the planner MOSFET because of better gate control mechanism. So, proposed Inverter would be efficacious to offer less power dissipation and higher speed. Objective: Impact of supply voltage, temperature, High-k gate oxide, TOX, TSI on the power, delay and voltage swing of the Inverter circuits have been detailed here. Methods: Extensive simulations using SILVACO ATLAS have been done to validate the proposed logic based digital circuits. Besides, the optimum supply voltage has been modelled and verified through simulation for low voltage operations. In depth analysis of voltage swing is added to measure the noise immunity of the proposed logic based circuits in Sub & Near-threshold operations. For ultra-low power operation, JLDG MOSFET can be an alternative compared to conventional planar MOSFET. Results: Hence, the analytical model of delay, power dissipation and voltage swing have been proposed of the proposed logic based circuits. Besides, the ultra-low power JLDG CMOS inverter can be an alternative in saving energy, reduction of power consumption for RFID circuit design where the frequency range is a dominant factor. Conclusion: The power consumption can be lowered in case of UHF, HF etc. RF circuits using the Double Gate Junction-less MOSFET as a device for circuit design.

Background: In recent years, there has been a high demand for executing digital signal processing and machine learning applications on energy-constrained devices. Squaring is a vital arithmetic operation used in such applications. Hence, improving the energy efficiency of squaring is crucial. Objective: In this paper, a novel approximation method based on piecewise linear segmentation of the square function is proposed. Methods: Two-segment, four-segment and eight-segment accurate and energy-efficient 32-bit approximate designs for squaring were implemented using this method. The proposed 2-segment approximate squaring hardware showed 12.5% maximum relative error and delivered up to 55.6% energy saving when compared with state-of-the-art approximate multipliers used for squaring. Results: The proposed 4-segment hardware achieved a maximum relative error of 3.13% with up to 46.5% energy saving. Conclusion: The proposed 8-segment design emerged as the most accurate squaring hardware with a maximum relative error of 0.78%. The comparison also revealed that the 8-segment design is the most efficient design in terms of error-area-delay-power product.

Objective: This paper presents a multi-objective design optimization of MEMS disk resonator using two techniques. Methods: Determining the optimized dimensions of disk resonator for a particular resonance frequency so as to achieve higher quality factor and lower motional resistance is attempted. One technique used is constraint-based multi-objective optimization using the interior-point algorithm. The second technique is based on multi-objective genetic algorithm. Results: The algorithms are implemented using MATLAB. The two techniques of optimization are compared. Conclusion: The developed optimization methods can provide faster design optimization compared to full-wave simulators resulting in significant reduction of design time.

Objective: In this paper, a novel third order sinusoidal oscillator based on current controlled differential difference current conveyor transconductance amplifier (CCDDCCTA) is proposed. Methods: The proposed circuit configuration consist of single CCDDCCTA, two grounded resistor and three capacitors. It can concurrently yield output voltage and current. The amplitude of output current can be easily tuned by the bias current. The non-ideality and Monte-Carlo analysis are discussed and presented. Results: The stated results agree well with the theoretical estimation. Conclusion: The performance ofa proposed oscillator are analyzed with ORCAD 16.6 simulator and the analog block has been depicted using 0.25 μm CMOS TSMC technology parameters.

Background: A microprocessor is a general-purpose device, which works on the user defined instructions. The design of next generation microprocessors demands high speed, high density and low power requirements that can be attained by prominent device like Single Electron Transistor (SET). Methods: Based on realizable SET parameters at room temperature and 800 mV operating voltage; an 8-bit SET based microprocessor is designed and simulated using Cadence Virtuoso environment. The simulation of the microprocessor requires complex stimuli to verify the design for multiple instructions. Conventionally, the simulation is performed by applying individual signal source to each signal. However, that is not optimum and viable for microprocessor designs. Results: The Cadence Spectre simulator has a facility to simulate the design using vector file, which combines multiple signal sources in a text file. In addition, writing vector file manually is complex and erroneous. Conclusion: To overcome the problem, a tool is designed and developed that generates a vector file for user selected instructions and parameters. The usage of vector file makes the simulation straightforward and accurate. This paper describes the design of a tool for vector file generation.

Aims: The potentiality of Multiple Quantum Well (MQW) Impacts Avalanche Transit Time (IMPATT) diodes based on Si~3C-SiC heterostructures as possible terahertz radiators have been explored in this paper. Objective: The static, high frequency and noise performance of MQW devices operating at 94, 140, and 220 GHz atmospheric window frequencies, as well as 0.30 and 0.50 THz frequency bands, have been studied in this paper. Methods: The simulation methods based on a Self-Consistent Quantum Drift-Diffusion (SCQDD) model developed by the authors have been used for the above-mentioned studies. Results: Thus the noise performance of MQW DDRs will be obviously better as compared to the flat Si DDRs operating at different mm-wave and THz frequencies. Conclusion: Simulation results show that Si~3C-SiC MQW IMPATT sources are capable of providing considerably higher RF power output with the significantly lower noise level at both millimeter-wave (mm-wave) and terahertz (THz) frequency bands as compared to conventional flat Si IMPATT sources.

Background: There has been an increasing curiosity over the past few years to carry out organic reactions over heterogeneous nanocatalysts. Microwave activation coupled with a nanocatalyst along with water as a reaction medium makes the process further green. Microwave activation as a green process reduces reaction times, enhances product purity and improves chemical yield. Methods: Nitrile group chemistry has been explored by many researchers across the globe owing to its interesting properties and its importance in synthetic chemistry. Despite several methods being available for the synthesis of nitriles, microwave assisted synthesis of nitriles using Fe3O4 nanoparticles appears more promising. The present study is intended at developing a recyclable magnetite (Fe3O4) nanoparticles catalyzed protocol towards the synthesis of organonitrile derivatives using one pot reaction. Results: The above protocol incorporates the use of microwave for heating and water as reaction medium. Several substituted nitriles could be synthesized for excellent yields. The magnetite nanoparticles can be reused for new reaction without significant loss in activity. Conclusion: The experiment makes the protocol simple, environment friendly and economically feasible.

Background: Cockleshell-derived aragonite calcium carbonate nanoparticles were prepared by the top-down approach for combine delivery of two types of drugs. Objective: The aim of this study was to synthesize and characterize thymoquinone-doxorubicin loaded cockle shell-derived aragonite calcium carbonate nanoparticle. Aragonite calcium carbonate nanoparticles encapsulating thymoquinone and doxorubicin alone were also prepared. Methods: The blank and drug-loaded nanoparticles were characterized by field emission scanning electron microscopy, transmission electron microscopy, Zeta potential, Fourier transformed infrared and X-ray diffraction. Drug delivery properties, in vitro drug release study at pH 7.4, 6 and 4.8, and effect of blank nanoparticles on MCF10A, 3T3, MDA MB231 cells were also analyzed. Results: The blank and drug-loaded nanoparticles were pleomorphic and their sizes varying from 53.65 ± 10.29 nm to 60.49 ± 11.36 nm with an overall negative charge. The entrapment efficiency of thymoquinone and doxorubicin were 41.6 and 95.8, respectively. The FTIR showed little alteration after loading thymoquinone and doxorubicin while XRD patterns revealed no changes in the crystallizations of nanoparticles after drug loading. The drug release kinetics of doxorubicin and thymoquinone from the nanoparticles showed a continuous and gradual release after an initial burst release was observed. At pH 4.8, about 100% of drug release was noticed, 70% at pH 6 while only 50% at pH 7.4. The cell viability was 80% at a concentration of 1000 ug/ml of blank nanoparticle. Conclusion: The cockle shell-derived pH sensitive aragonite calcium carbonate nanoparticle provides an effective and simple means of multiple drug delivery and function as a platform for pH controlled release of loaded therapeutic agents.

Background: The advancement of VLSI in the application of emerging nanotechnology explores quantum-dot cellular automata (QCA) which has got wide acceptance owing to its ultra-high operating speed, extremely low power dissipation with a considerable reduction in feature size. The QCA architectures are emerging as a potential alternative to the conventional complementary metal oxide semiconductor (CMOS) technology. Experimental: Since the register unit has a crucial role in digital data transfer between the electronic devices, such study leading to the design of cost-efficient and highly reliable QCA register is expected to be a prudent area of research. A thorough survey on the existing literature shows that the generic models of Serial-in Serial Out (SISO), Serial-in-Parallel-Out (SIPO), Parallel-In- Serial-Out (PISO) and Parallel-in-Parallel-Out (PIPO) registers are inadequate in terms of design parameters like effective area, delay, O-Cost, Costα, etc. Results: This work introduces a layered T gate for the design of the D flip flop (LTD unit), which can be broadly used in SISO, SIPO, PISO, and PIPO register designs. For detection and reporting of high susceptible errors and defects at the nanoscale, the reliability and defect tolerant analysis of LTD unit are also carried out in this work. The QCA design metrics for the general register layouts using LTD unit is modeled. Conclusion: Moreover, the cost metrics for the proposed LTD layouts are thoroughly studied to check the functional complexity, fabrication difficulty and irreversible power dissipation of QCA register layouts.

Background: This study aims to study the mixing of graphite with water irradiated by X-ray (low energy gamma ray) towards the formation of graphene oxide (GO). Methods: The graphite is obtained from Zinc-Carbon (ZnC) battery wastes. This is a simple alternative technique in synthesizing GO based on X-ray irradiation without involving additional chemicals. X-ray irradiation is conducted upon 10 ml of distilled water using 20 kV of X-ray with irradiation time variation of 3 and 4 h. The X-ray irradiation towards the distilled water causes radiolysis to occur in the water. The graphite solution consists of 0.6 gm of graphite in 100 ml of distilled water. The GO is formed by mixing the X-ray irradiated water with 5 drops of the graphite solution. The sample solutions obtained are shaken several times and left to settle for a night. The samples are then characterized using UV-Visible (UV-Vis) and Fourier transform infra-red (FTIR) spectroscopies, and tunneling electron microscopy (TEM), whereas scanning electron microscope and energy dispersive X-ray (SEM-EDX) characterization is done by coating the sample on glass slides. Results: The UV-Vis characterization results show a red shift of absorbance peaks from 234.5 nm to 244.5 nm as the time of irradiation is increased. These peaks indicate the formation of GO in the samples. The FTIR characterization results indicate that there are functional groups of OH, C=C, and C-O in the samples, which also show the existence of GO. The SEM images show the surface morphology of the sample, which resembles smooth-quadrilateral lump of clays, and the EDX result shows that the sample is composed of 2.86%, 54.02%, 11.62%, 2.2%, 26.23%, and 3.06% of carbon, oxygen, sodium, magnesium, silicon, and calcium atoms, respectively. The occurrence of carbon and oxygen atoms verifies further the formation of GO in the samples. Conclusion: Finally, the TEM result shows few-layers of GO materials supported by the electron diffraction pattern showing hexagonal structure of the GO.