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In this study, the clove essential oil-loaded nanoemulsion system was prepared using corn and soybean oils as a coating agent for refrigerated chicken fillets, and its bio preservative properties were investigated during 15 days at 4 °C. A total of 6 compounds were identified from the clove essential oil, with the dominant compounds being eugenol (88.38%) and beta-caryophyllene (6.01%). The coating process led to the reduction of titratable acidity of the chicken fillets during the storage time. Compared to non-coated samples, nanoemulsion-treated samples presented less increase in peroxide value (from 0.057 to 0.089) and thiobarbituric acid (from 0.234 to 0.835) values along the storage time. Increasing the content of clove essential oil in the nanoemulsions resulted in a significant reduction in total volatile basic nitrogen content. The coating process was highly effective in decreasing the total viable count, and psychrophilic bacteria growth, while antimicrobial activity varied depending on the nanoemulsion formulation and storage time. Using the nanoemulsions containing 1% clove essential oil led to a significant increase in sensory parameter scores. Therefore, the treatment containing 1% clove essential oil due to the highest acceptability score was chosen as the best treatment.

One way to achieve high performance in the gas turbine is to increase the inlet temperature of the turbine. Different cooling techniques have been carried out in order to protect the turbine blades which have been exposed to such high temperatures. Film cooling as an essential cooling method needs to be enhanced to meet the challenging demand. The purpose of the present research is to analyze the film cooling performance over a NACA 0012 gas turbine blade using six different injection holes with and without opening angles, separately through Computational Fluid Dynamics (CFD). 2D Reynolds-Averaged Navier-Stokes (RANS) equations are implemented to consider the heat transfer and flow characteristics by using CFD code Ansys Fluent v16. The flow is considered as steady, turbulent, and incompressible. The RANS equation is solved with the finite-volume method for obtaining solutions. The simulation results revealed that the k-ω SST turbulence model is suitable for simulating the flow characteristics and analyzing the performance of film cooling over the blade. Also, the opening angle has a significant effect on increasing the cooling efficiency for the upper blade surface. The highest value of cooling efficiency is obtained by the injection hole with an opening angle of 15° and height of D. In this configuration, the coolant injected from hole provides better cooling coverage for the entire blade which increases the cooling effectiveness.

In this study, the physicochemical, mechanical, and antimicrobial activities of polyethylene (PE) films coated with peppermint (Menthol) and Origanum vulgare (Carvacrol) essential oil were evaluated. For this reason, PE films were coated with MC‐HPMC solution containing different concentrations of menthol and carvacrol (0, 1, 1.5, and 2%), and mechanical, electromagnetic, barrier, and antimicrobial properties of all prepared films were examined. The obtained results demonstrated that by increasing the concentration of menthol and carvacrol in film coatings, tensile strength (from 36 to 23 MPa), water vapor permeability (from 12 to 11 g.m‐1s‐1Pa‐1), and L* and b* indexes were decreased, while the oxygen permeability (OP) and elongation at break significantly were increased (p, Carvacrol and menthol were used as two natural antimicrobial agents in active packaging. PE films by coating is an effective method to making active packaging.

Resonant-tunneling diodes (RTDs) based on graphene nanoribbons have attracted the attention of many researchers recently. In this article, we propose a new RTD based on graphene nanoribbon/h-boron nitride. In this structure, two hexagonal boron nitride (h-BN) slices are used as potential barriers to form a double-barrier structure, due to the higher bandgap of h-BN. Two gate electrodes are used in order to control the peak-to-valley current ratio (PVR). In the proposed structure, a PVR of 1.11 at a valley current of $5.56~\mu \text{A}$ and a PVR of 2.41 at a valley current of $0.49~\mu \text{A}$ have been obtained that are better than many reported structures in the literature. The proposed structure is a suitable candidate for use in various high current RTD-based applications. A numerical tight-binding model coupled with nonequilibrium Green’s function formalism is used for simulation and studying electronic properties of this structure.

Nanotube (such as carbon and boron nitride nanotubes) is a key component of modern technology applications of nanostructures due to their unique mechanical, electrical, and physical characteristics such as high elasticity modulus, suitable heat transfer, and electrical conductivity. Carbon and boron nitride nanotubes are among the promising choices in nano-fluidic, gas storage, and drug delivery systems due to their hollow cylindrical shape and appropriate chemical, mechanical, and physical properties. Thermal vibration assessment should be conducted on fluid-conveying carbon nanotubes since the effect of thermal fluctuations on the mechanical characteristics of nanostructure are significant. Previous studies have revealed that when thermal vibration is taken into account, quantum effects can become extremely important in nanoscale electronics and structures. Hence, the present review focuses mostly on previous work on fluid-conveying nanotubes and the dynamical characteristics of size-dependent vibration and non-local strain gradient theory of fluid-conveying nanotubes. Furthermore, a special effort is made to address recent and rare investigations on the vibration of fluid-conveying nanotubes in thermal environment, as well as thermal vibration concerns of carbon nanotubes.

Two new vertical resonant tunneling devices (RTDs) of different sizes are proposed herein to achieve negative differential resistance with enhanced tunneling and peak-to-valley ratio (PVR) stability. The proposed structures are of the form n+–p−–p+ (S2) and n+–[p−–n+]–p−–p+ (S1) with different electrodes made of parallel graphene nanoribbon and graphene sheet (S2) or bilayer graphene (S1). The results of the simulations show a PVR of 3–3.5 depending on the geometry of the structure, with a maximum current of 10 μA. Also, robust PVR values in the range of 1.2–1.5 are obtained for these structures for a wide range of dimensions. An approximate analytical model for the I–V curve under the assumption of a vertical van der Waals bonding stacked structure as equivalent to the complex horizontal channel is introduced.

Background: Pre-drying operations and drying methods have a significant effect on the quantity and quality of plants essential oils. Objective: In this study, the effect of pre-drying operation and vacuum oven-drying was investigated on the essential oil content and composition of Lippia citriodora. Method: This research was conducted as a factorial experiment in a completely randomized design (CRD) with three replications. The two studied factors were (1) pre-drying operations in two levels including pre-drying and without pre-drying operation, and also (2) drying methods in 5 levels including fresh plant, shade drying and vacuum oven-drying at 35, 45 and 55°C at 0.5 bar atmospheric pressure. In this study, the amount of pigments and essential oil content and composition were measured. Results: The results indicated that the highest chlorophyll content was related to treatment of vacuum oven-drying at 55 °C with a pre-drying treatment, while the highest amount of essential oil was obtained by vacuum oven-drying at 45 °C without a pre-drying operation. The highest amounts of monoterpene hydrocarbons, oxygenated monoterpenes, and geranial were obtained by drying at 55 °C, while the highest content of sesquiterpene hydrocarbons, oxygenated sesquiterpenes and neral were observed in Low-temperature drying. Conclusion: In general, this study indicated that vacuum oven-drying at 45 °C was the best drying method for obtaining maximum content of essential oil and active components.

A configurable terahertz (THz) graphene-based metamaterial absorber is designed in this paper. Taking advantage of dual bias graphene ribbons and disks with a golden plate, the reconfigurable absorber achieves absorption over 90% in three frequency bands include 0.8–2.2 THz, 5.5–6.5 THz and 7.5–8.5 THz. The chemical potentials of graphene patterns are optimized using a genetic algorithm. As the chemical potentials vary in the range of 0-0.6 eV, the device adds absorption bands while maintaining the previous absorption in lower frequencies. The whole device includes dielectrics, golden plate, and dual bias graphene patterns are modeled via the circuit model approach to calculate referred input impedance. This impedance is investigated regarding chemical potential effects on perfect absorption while other physical parameters such as ribbons widths and disks radiuses are fixed. Finally, the obtained suggestions of the algorithm are exploited to simulate the device with both full-wave numerical simulations as the finite element method (CST) and circuit model approach (MATLAB). According to simulation results, numerical simulation verifies validity and accuracy of circuit modeling to describe proposed device behavior. Compared to previous works, the proposed device as a reconfigurable THz absorber can overcome the limitation of traditional absorbers due to the capability of an add frequency band in absorption response while exhibits great potentials in many practical applications.

Heterocyclic aromatic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) as carcinogenic chemical compounds can be formed during high-temperature heating of beef patties. The current study was aimed to evaluate the effects of nutmeg and ginger essential oils incorporated in two concentrations (0.02 and 0.04%) and their nanoemulsions on the HCAs and PAHs formation in grilled beef patties during production time, 45- and 90-days storage in a freezing condition at − 18 °C. According to results, the HCAs and PAHs levels in essential oil and nanoemulsion added grilled beef patties significantly decreased while compared to the control. The addition of 0.04% nutmeg oil nanoemulsion in grilled beef patties led to the highest reduction in 2-amino-3,4-dimethyl-imidazo[4,5-f] quinoline (100% reduction) and benzo [b] fluorantene (46% reduction). The storage time of beef patties significantly affected the concentration of HCAs and PAHs. In this context, with increase in storage time, the levels of HCAs and PAHs were decreased and increased, respectively. The formation of 2-amino-3,4-dimethyl-imidazo[4,5-f] quinoline in all grilled beef patties containing nutmeg oil and its nanoemulsion was reduced by 100% after 45 and 90 days storage. However, the lowest increase in the formation of PAHs was related to dibenzo [a,h] anthracene by 25% in grilled beef patties containing 0.04% nutmeg oil nanoemulsion at the end of storage time. Generally speaking, nutmeg oil and especially prepared nanoemulsion have a great impact in preventing of the carcinogens compound formation in grilled patties.

In this study, the effect of chitosan film (CF) with different concentrations of anise essential oil AEO (0, 0.5, 1, 1.5 and 2%) on the quality of chicken burger during chilled storage (4 + 1°C) were examined over a period of 12 days. For this purpose, at the first, the physical and mechanical properties of the produced films were studied. Then, the chicken burger was covered with the produced films. Different treatment were analyzed by biochemical properties such as moisture and thiobarbituric acid, bacteriological properties such as total viable counts and total psychrotrophic counts, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. The results of this study showed that adding AEO improved the properties of CF, the moisture, solubility, and water vapor permeability decreased in these films. By increasing the concentration of AEO the tensile strength and elasticity of film were increased. CF with AEO, delayed lipid oxidation in chicken burger and improved the chemical properties of chicken burger. Also, microbial spoilage in these samples decreased significantly (p

In this paper, we analytically investigate the effects of the two samples of mechanical deformations, i.e., uniaxial and torsional strains on the electronic band structure and the density of states of the single-walled carbon nanotubes (SWCNTs) using the nearest neighbor, the third-nearest neighbor (3-NN-TB) and the fifth-nearest neighbor tight-binding (5-NN-TB) approaches to compare the estimated band gap and the density of states of the three methods. To do this, we not only make use of the previous works but also analytically develop a 5-NN-TB-based model for the investigation of the mentioned types of strains. The purpose of this paper is to employ this model for the investigation of the two types of strain in order to acquire an analytic formula for the band structure under strain and get the advantage of analytic formula (e.g., speed in band structure calculations under strain) in conjunction with the high degrees of accuracy.

The effects of a sunflower oil-based nanoemulsion containing different concentrations of Zataria multiflora Boiss. essential oil (ZMEO, 0.0%, 0.5% and 1%) on the freshness of rainbow trout ( Oncorhynchus mykiss ) fillets were evaluated by determining the physicochemical and sensory properties during storage at 4 ± 1 °C. The thiobarbituric acid (TBA), total volatile basic nitrogen (TVB-N), peroxide value (PV), free fatty acids (FFA) and pH were determined on days 0, 5, 10 and 15. The results revealed that the nanoemulsion and ZMEO had synergistic effects on reducing lipid oxidation, as judged by determination of the TBA, FFA and TVB-N, thus extending the shelf life of rainbow trout fillets by at least 15 days. The inhibitory effects of the nanoemulsion were closely related to the concentration of ZMEO due to its high contents of carvacrol and thymol. The quality of fillets treated with the nanoemulsion and 1% ZMEO was significantly different compared with other treatments. Incorporation of ZMEO and the nanoemulsion increased the taste, odour and texture acceptability. Therefore, the nanoemulsion developed in this study could inhibit the development of lipid oxidation during storage at 4 ± 1 °C, representing an option as a food preservative.

Due to the unfavorable effects of synthetic antioxidants, the use of various sources of plant antioxidants to prevent foods oxidation, especially oil-based or fat-based varieties, has been recently got considerable attention. In this study, the antioxidant effect of essential oil and extract from the citron fruit (Citrus medica L.) was investigated on the thermal stability of sunflower oil. Aqueous, ethanolic, and methanolic extracts of citron peel (800 ppm), BHT synthetic antioxidant (200 ppm), and citron peel essential oil (800 ppm) were added to sunflower oil. The oil oxidation stability was evaluated during 5 days through analyzing the values of peroxide, anisidine, thiobarbituric acid, totox, and oxidative stability index (OSI). Results showed that the peroxide, anisidine, and totox value had an increasing trend over time. The effects of storage time, extract, and essential oil were statistically significant in reducing the oxidation rate of sunflower oil during storage. Ultrasonic-assisted ethanolic extract at 30 min showed the highest OSI. The results of this study demonstrated the positive effects of citron peel extract essential oil and on sunflower oil stability and its superiority over synthetic antioxidants.

In this paper, a wideband synthesizer with output range of 2.1GHz-2.5GHz and resolution of 1MHz and input reference of 50Mhz is proposed. In this method, firstly, by the Integer-N synthesizer based on PLL and constructed of blocks of PFD, CP, VCO and Frequency divider the input is increased with integer coefficients and it produces frequencies 2.1GHz, 2.15GHz,..., 2.5GHz very quickly. To get 1MHz steps in the output, a second loop that consists of blocks FVC, VCO and Voltage divider is used. In this method, the input frequency is high compared to the conventional methods, so the first loop will be locked very fast and the second loop will quickly move the output in steps 1MHz. As a result, changing channels will be very quick. This structure is very simple and has a low power consumption and a low output jitter, the proposed structure is designed in 0.18um CMOS process.

Negative Differential Resistance (NDR) is a well-known phenomenon in I-V characteristic of some electron devices such as Resonant Tunneling Diodes (RTDs), Esaki diode and resonant tunneling transistors. In this article a Double Barrier Quantum Well structures (DBQW) resonant tunneling diode has been proposed based on graphene nanoribbon and hexagonal-Boron Nitride. Three different channel RTD structures constructed from ZGNRs are proposed. In these structures, highest peak current of 2.1 µA, and lowest valley current 100nA is achieved. The transport properties of DBQW are explored by Non-Equilibrium Green's-Function (NEGF) formalism.

Yogurt drinks can potentially be an appropriate medium for delivering probiotics to consumers. This study investigated the influences of the water-soluble fraction of bitter almond gum (SBAG) and its conjugate with sodium caseinate (SBAG-SC) compared to carboxymethylcellulose (CMC) and inulin, respectively, on the physical stability of casein micelles and the viability of the probiotic culture (Lactobacillus acidophilus La-5) in probiotic yogurt drink during cold storage. The addition of SBAG-SC conjugate to the drinks successfully prevented phase separation for a longer time than CMC. CMC-based drinks exhibited a strong shear-thinning response. Adding SBAG helped keep Lactobacillus acidophilus La-5 viable above the recommended level for probiotic products. However, the SBAG showed relatively less prebiotic property than inulin. This study demonstrated that SBAG-SC conjugate has a high potential for stabilizing applications in yogurt and yogurt products.

In this paper, a three-dimensional (3D) analytical solution of the electrostatic potential is derived for the tri-gate tunneling field-effect transistors (TG TFETs) based on the perimeter-weighted-sum approach. The model is derived by separating the device into a symmetric and an asymmetric double-gate (DG) TFETs and then solving the 2D Poisson's equation for these structures. The subthreshold tunneling current expression is extracted by numerical integrating the band-to-band tunneling generation rate over the volume of the device. It is shown that the potential distributions, the electric field profile, and the tunneling current predicted by the analytical model are in close agreement with the 3D device simulation results without the need of fitting parameters. Additionally, the dependence of the tunneling current on the device parameters in terms of the gate oxide thickness, gate dielectric constant, channel length, and applied drain bias is investigated and also demonstrated its agreement with the device simulations.

A new analytical model for the subthreshold swing of nanoscale undoped trigate silicon-on-insulator metal---oxide---semiconductor field-effect transistors (MOSFETs) is proposed, based on the channel potential distribution and physical conduction path concept. An analytical model for the potential distribution is obtained by solving the three-dimensional (3-D) Poisson's equation, assuming a parabolic potential distribution between the lateral gates. In addition, mobile charges are considered in the model. The proposed analytical model is investigated and compared with results obtained from 3-D simulations using the ATLAS device simulator and experimental data. It is demonstrated that the analytical model predicts the subthreshold swing with good accuracy for different lengthes, thicknesses, and widths of channel.

An important issue in devices with negative differential resistance (NDR) in I–V characteristics is the ability to control device characteristics. In this paper, a novel double-gate AGNR/h-BN FET with a tunable NDR in the I–V characteristic is proposed for the first time. An armchair GNR is used in this device with length of 6.4 nm and width of 2.2 nm. The insulator used in this device is silicon oxynitride due to higher dielectric constant compared with silicon dioxide in order to improve gate control, and more feasibility than high-k materials since it has native silicon oxide. The interesting feature of this device is its ability to tune NDR in the output characteristics. It is observed that positive gate-source voltages reduce the peak to valley current differences and, negative gate-source voltages increase the peak to valley current differences. By tuning the NDR, the biasing condition and even the oscillation condition of the transistor can be tuned when it is used as an oscillator, for example. In addition, the current and power consumption of the device can be controlled.

In this paper, a new high-speed and low power unsigned multiplication structure is proposed: based on the proposed algorithm, the input bits of multiplier are broken into several smaller groups of bits and the multiplication of them are calculated concurrently. The final product of multiplication is generated after several rounds of the small group's results aggregation. A 32*32-bit multiplier according to the proposed structure is designed in 0.18um CMOS process. The overall delay of 32*32-bit multiplier is extremely low and is only 2.1ns. The power consumption is 41mW.

Graphene, a purely two-dimensional sheet of carbon atoms, as an attractive substrate for plasmonic nanoparticles is considered because of its transparency and atomically thin nature. Additionally, its large surface area and high conductivity make this novel material an exceptional surface for studying adsorbents of diverse organic macromolecules. Although there are plenty of experimental studies in this field, the lack of analytical model is felt deeply. Comprehensive study is done to provide more information on understanding of the interaction between graphene and DNA bases. The electrostatic variations occurring upon DNA hybridization on the surface of a graphene-based field-effect DNA biosensor is modeled theoretically and analytically. To start with modeling, a liquid field effect transistor (LGFET) structure is employed as a platform, and graphene charge density variations in the framework of linear Poisson– Boltzmann theories are studied under the impact induced by the adsorption of different values of DNA concentration on its surface. At last, the artificial neural network is used for improving the curve fitting by adjusting the parameters of the proposed analytical model.

In this paper we investigate the effect of uniaxial and torsional strains on the Density of States (DOS) of single walled Carbon nanotubes (SWCNTs). We employ the nearest neighbor and the third nearest neighbor π-TB (Tight Binding) models for our investigation. It is shown that uniaxial and torsional strains in some cases of metallic SWCNTs not only open a band gap but also effectively increase the DOS of SWCNT. It is also shown that, the mentioned types of strain have different effects on the DOS of chiral SWCNTs; in some types, they increase the DOS at the band edges while in other types they decrease it at the band edges.

In this study, a gallium nitride (GaN) high electron mobility transistor (HEMT) with recessed insulator and barrier is reported. In the proposed structure, insulator is recessed into the barrier at the drain side and barrier is recessed into the buffer layer at the source side. We study important device characteristics such as electric field, breakdown voltage, drain current, maximum output power density, gate-drain capacitance, short channel effects and DC transconductance using two-dimensional and two-carrier device simulator. Recessed insulator in the drain side of the proposed structure reduces maximum electric field in the channel and therefore increases the breakdown voltage and maximum output power density compared to the conventional counterpart. Also, gate-drain capacitance value in the proposed structure is less than that of the conventional structure. Overall, the proposed structure reduces short channel effects. Because of the recessed regions at both the source and the drain sides, the average barrier thickness of the proposed structure is not changed. Thus, the drain current of the proposed structure is almost equivalent to that of the conventional transistor. In this work, length (L r) and thickness (T r) of the recessed region of the barrier at the source side are the same as those of the insulator at the drain side.

The radio-frequency (RF) performances and small-signal parameters of double-gate (DG) square-shaped extended source tunneling field-effect transistors (TFETs) with different gate lengths have been extracted and compared with those of conventional TFETs in terms of cut-off frequency, maximum oscillation frequency, current gain, unilateral power gain, gate-source capacitance, gate-drain capacitance, channel resistance, time constant and transconductance. The small-signal parameters have been extracted by using of a nonquasistatic radio-frequency model, which were verified up to 250 GHz. Because of the higher transconductance and current drivability and smaller gate capacitance of DG square-shaped extended source TFETs compared to conventional TFETs, DG square-shaped extended source TFETs have higher cut-off and maximum oscillation frequencies and smaller switching time. The impact of high- κ gate dielectric on RF figures of merit and device performance has also been investigated for extended source TFET. The results showed close agreement between the Y -parameters and the extracted parameters of modeling, SPICE simulation and device simulation for high frequency range up to the cut-off frequency.

A carbon nanotube field effect transistor (CNTFET) has been studied based on the Schrödinger–Poisson formalism. To improve the saturation range in the output characteristics, new structures for CNTFETs are proposed. These structures are simulated and compared with the conventional structure. Simulations show that these structures have a wider output saturation range. With this, larger drain-source voltage (Vds) can be used, which results in higher output power. In the digital circuits, higher Vds increases noise immunity.

This paper presents radio-frequency (RF) modeling of p-n-p-n double-gate tunneling field-effect transistors (TFETs). The p-n-p-n TFETs are evaluated for various RF parameters such as cut-off frequency, maximum oscillation frequency, gate-source capacitance, gate-drain capacitance, channel resistance, and transconductance. Direct comparisons of high-frequency performances and extracted parameters are made with conventional TFETs. A nonquasistatic radio-frequency model has been used, along with SPICE simulations to investigate p-n-p-n TFETs with RF parameters extracted from TCAD simulation Y-parameters. The results show excellent agreements with the TCAD simulation results for the high frequency range up to the cut-off frequency for the millimeter-wave applications.

The comprehensive optical-electrical-gain-thermal self-consistent model of the 1.55 μm AlGaInAs Photonic Crystal vertical cavity surface emitting diode lasers (PhC VCSELs) with buried tunnel junction (BTJ) has been applied to optimize its threshold characteristics. It shows that, for 5 μm devices, the room temperature (RT) threshold current equal to only 0.59 mA and maximum operating temperature equal to as much as 380 K. Results suggest that, the 5 μm AlGaInAs PhC VCSELs seem to be the most optimal ones for light sources in high performance optical communication systems.

In this paper, a silicon–on–insulator (SOI) p–n–p–n tunneling field–effect transistor (TFET) with a silicon doped hafnium oxide (Si:HfO2) ferroelectric gate stack is proposed and investigated via 2D device simulation with a calibrated nonlocal band–to–band tunneling model. Utilization of Si:HfO2 instead of conventional perovskite ferroelectrics such as lead zirconium titanate (PbZrTiO3) and strontium bismuth tantalate (SrBi2Ta2O9) provides compatibility to the CMOS process as well as improved device scalability. By using Si:HfO2 ferroelectric gate stack, the applied gate voltage is effectively amplified that causes increased electric field at the tunneling junction and reduced tunneling barrier width. Compared with the conventional p–n–p–n SOI TFET, the on–state current and switching state current ratio are appreciably increased; and the average subthreshold slope (SS) is effectively reduced. The simulation results of Si:HfO2 ferroelectric p–n–p–n SOI TFET show significant improvement in transconductance (∼9.8X enhancement) at high overdrive voltage and average subthreshold slope (∼35% enhancement over nine decades of drain current) at room temperature, indicating that this device is a promising candidate to strengthen the performance of p–n–p–n and conventional TFET for a switching performance.

In this paper a new structure for BJT-transistor based on SOI technology has been designed. This structure has an extra pin as a gate. By applying a voltage to the gate, the effective base width is controlled, and this gives the ability to control the transistor gain. This transistor is investigated via extensive simulations. All simulations have been performed using Silvaco software showing current gain variations up to 10 times. The current gain of the transistor without any gate voltages is about 200, which increases to 2000 by increasing the gate voltage. This gives potential applications, like mixers and gain controls with a good performance. In this paper, the doping levels distributions have been designed to achieve the best current gain and output conductance.

In this paper numerical optimum base doping for minimum base transit time is presented. The bandgap-narrowing effect, high-injection effect, and carrier velocity saturation at the base edge of the base collector junction, and also doping and field dependence of mobility, are considered. Many doping profile are investigated including, linear, exponential doping concentration, we assumed uniform, exponentially and Gaussian doping profiles. Base transit time is investigated numerically for optimum base doping profile.

In this paper we propose a new dual gate SOI-MOSFET in order to reduce short-channel effects (SCEs). In the proposed structure, the bias of the second gate which is near the drain is dependent on the drain voltage. To investigate transistor characteristics, a two-dimensional (2-D) analytical model for the surface potential variation along the channel is developed. A comparison between our structure and the single-gate (SG) SOI MOSFET demonstrates that short channel effects like, hot carriers effect and the drain induced barrier lowering (DIBL) are reduced considerably in the proposed structure.

In this paper the effects of random distribution fluctuations of dopants in the channel of a nano-scale SOI-MOSFET are investigated via simulations. Simulations are performed using energy balance model. According to obtained results, the threshold voltage is subjected to variations due to non-uniform distribution of dopants under the gate.

In this paper a new transistor of dual-gate (DG) silicon-on- insulator (SOI) MOSFET is presented. The objects of this paper are to use a voltage difference between the two gates to screen the drain voltage and therefore reduce short channel effects (SCEs). In this transistor the surface potential exhibits a step function, which causes the screening of the drain potential. This results in suppressed SCEs such as the hot-carrier effect and decreasing off-current with respect to shrinking of channel length. The obtained results of our transistor are compared to single gate (SG) SOI MOSFET that shows the DG SOI MOSFET performance is superior. The transistor has been simulated by SILVACO software.

The drift-diffusion (DD) model is not accurate for simulation of sub-micrometer semiconductor devices. Using RBF NN, a neuro space mapping is proposed to DD model parameters. The DD model with mapped parameters can produce accurate simulation results of the hydrodynamic model. Simulations of a SOI-MOSFET confirm the ability of the proposed method for submicron device simulation.

In this paper a two-dimensional (2-D) analytical model for the surface potential variation along the channel in a fully depleted dual?gate silicon-on-insulator MOSFETs is proposed to investigate the short-channel effects (SCEs). We demonstrate that the surface potential in the channel region exhibits a step function which causes the screening of the drain potential by the gate near the drain resulting in suppressed SCEs like hot-carrier effect and drain-induced barrier-lowering (DIBL).

In this paper the effect of the gate length on the operation of SOI-MOSFETs is evaluated via simulations. Three transistors with gate lengths 100, 200 and 500 nm are simulated. Simulations show that with a fixed channel length, when the gate length is increased, the curve slope ID-VGS is increased, and therefore the transistor trans-conductance increases. Moreover, with increasing the gate length, the effect of the drain voltage on the drain current is reduced, which results in decreasing of the drain induced barrier lowering (DIBL).

This paper presents a radio-frequency (RF) small-signal model for the hetero-gate-dielectric p-n-p-n tunnel field-effect transistor (HG p-n-p-n TFET) that includes the charge conservation capacitance and the substrate parameters. The HG p-n-p-n TFET is evaluated in terms of various RF parameters, including the cut-off frequency, the maximum oscillation frequency, capacitances, resistances, conductances, and transport time delay. The extracted small-signal parameters and RF performance values are compared with those of the low-κ p-n-p-n TFET. A nonquasistatic RF small-signal model has been used along with SPICE simulations and small-signal parameters that were extracted from the simulated device Y-parameters to simulate the HG p-n-p-n TFET. It is confirmed using the Y-parameters and the extracted parameters that this model with the extracted charge conservation capacitance and substrate parameters is valid in the high frequency range up to 100 GHz. In addition, it is shown that a significant circuit performance error may be introduced if the charge conservation capacitance and the substrate parameters are not considered appropriately.

In this paper, a simple and accurate analytical model for current–voltage and small-signal characteristics of Al m Ga1-m N/GaN modulation doped field-effect transistor (MODFET) devices is presented. For the charge control model, Fermi potential variation with sheet carrier concentration, the infiltration of a two-dimensional electron gas wave function into the spacer layer, and the effects of spontaneous and piezoelectric polarizations at the heterointerface are considered. Also, parasitic source/drain resistances have been incorporated in the analysis. In addition, a suitable drift velocity model and the gate voltage dependence of low-field mobility are used to provide simple and accurate equations for the different characteristics of AlGaN/GaN MODFET devices. By implementing the model in the MATLAB environment, current–voltage characteristics, transconductance, output conductance, capacitance–voltage characteristics, and cutoff frequency have been calculated. A comparison of simulation results with published experimental data for Al0.15Ga0.85N/GaN shows excellent agreement, thereby proving the validity of the model.