In this work,forward current voltage characteristics for multi-quantum wells Al_(0.33)Ga_(0.67)As Schottky diode were measured at temperature ranges from 100 to 300 K.The main parameters of this Schottky diode,such as...In this work,forward current voltage characteristics for multi-quantum wells Al_(0.33)Ga_(0.67)As Schottky diode were measured at temperature ranges from 100 to 300 K.The main parameters of this Schottky diode,such as the ideality factor,barrier height,series resistance and saturation current,have been extracted using both analytical and heuristics methods.Differential evolution(DE),particle swarm optimization(PSO)and artificial bee colony(ABC)have been chosen as candidate heuristics algorithms,while Cheung technic was selected as analytical extraction method.The obtained results show clearly the high performance of DE algorithms in terms of parameters accuracy,convergence speed and robustness.展开更多
Extraction of accurate Photo Voltaic (PV) model parameters is a challenging task for PV simulator developers. To mitigate this challenging task a novel approach using Gravitational Search Algorithm (GSA) for accurate ...Extraction of accurate Photo Voltaic (PV) model parameters is a challenging task for PV simulator developers. To mitigate this challenging task a novel approach using Gravitational Search Algorithm (GSA) for accurate extraction of PV model parameters is proposed in this paper. GSA is a population based heuristic optimization method which depends on the law of gravity and mass interactions. In this optimization method, the searcher agents are collection of masses which interact with each other using laws of gravity and motion of Newton. The developed PV model utilizes mathematical equations and is described through an equivalent circuit model comprising of a current source, a diode, a series resistor and a shunt resistor including the effect of changes in solar irradiation and ambient temperature. The optimal values of photo-current, diode ideality factor, series resistance and shunt resistance of the developed PV model are obtained by using GSA. The simulations of the characteristic curves of PV modules (SM55, ST36 and ST40) are carried out using MATLAB/Simulink environment. Results obtained using GSA are compared with Differential Evolution (DE), which shows that GSA based parameters are better optimal when compared to DE.展开更多
Several parameters of a commercial Si-based Schottky barrier diode (SBD) with unknown metal material and semiconductor-type have been investigated in this work from dark forward and reverse I-V characteristics in the ...Several parameters of a commercial Si-based Schottky barrier diode (SBD) with unknown metal material and semiconductor-type have been investigated in this work from dark forward and reverse I-V characteristics in the temperature (T) range of [274.5 K - 366.5 K]. Those parameters include the reverse saturation current (I<sub>s</sub>), the ideality factor (n), the series and the shunt resistances (R<sub>s</sub> and R<sub>sh</sub>), the effective and the zero bias barrier heights (Φ<sub>B</sub> and Φ<sub>B0</sub>), the product of the electrical active area (A) and the effective Richardson constant (A**), the built-in potential (V<sub>bi</sub>), together with the semiconductor doping concentration (N<sub>A</sub> or N<sub>D</sub>). Some of them have been extracted by using two or three different methods. The main features of each approach have been clearly stated. From one parameter to another, results have been discussed in terms of structure performance, comparison on one another when extracted from different methods, accordance or discordance with data from other works, and parameter’s temperature or voltage dependence. A comparison of results on Φ<sub>B</sub>, ΦB0</sub>, n and N<sub>A</sub> or N<sub>D</sub> parameters with some available data in literature for the same parameters, has especially led to clear propositions on the identity of the analyzed SBD’s metal and semiconductor-type.展开更多
This paper proposes a design and fine-tuning method for mixed electric and magnetic coupling filters.It derives the quantitative relationship between the coupling coefficients(electric and magnetic coupling,i.e.,EC an...This paper proposes a design and fine-tuning method for mixed electric and magnetic coupling filters.It derives the quantitative relationship between the coupling coefficients(electric and magnetic coupling,i.e.,EC and MC)and the linear coefficients of frequencydependent coupling for the first time.Different from the parameter extraction technique using the bandpass circuit model,the proposed approach explicitly relatesEC and MC to the coupling matrix model.This paper provides a general theoretic framework for computer-aided design and tuning of a mixed electric and magnetic coupling filter based on coupling matrices.An example of a 7th-order coaxial combline filter design is given in the paper,verifying the practical value of the approach.展开更多
An accurate and novel small-signal equivalent circuit model for GaN high-electron-mobility transistors(HEMTs)is proposed,which considers a dual-field-plate(FP)made up of a gate-FP and a source-FP.The equivalent circui...An accurate and novel small-signal equivalent circuit model for GaN high-electron-mobility transistors(HEMTs)is proposed,which considers a dual-field-plate(FP)made up of a gate-FP and a source-FP.The equivalent circuit of the overall model is composed of parasitic elements,intrinsic transistors,gate-FP,and source-FP networks.The equivalent circuit of the gate-FP is identical to that of the intrinsic transistor.In order to simplify the complexity of the model,a series combination of a resistor and a capacitor is employed to represent the source-FP.The analytical extraction procedure of the model parameters is presented based on the proposed equivalent circuit.The verification is carried out on a 4×250μm GaN HEMT device with a gate-FP and a source-FP in a 0.45μm technology.Compared with the classic model,the proposed novel small-signal model shows closer agreement with measured S-parameters in the range of 1.0 to 18.0 GHz.展开更多
The mathematical modeling of solar cells is essential for any optimization operation of the efficiency or the diagnosis of photovoltaic generator. The photovoltaic module is generally represented by an equivalent circ...The mathematical modeling of solar cells is essential for any optimization operation of the efficiency or the diagnosis of photovoltaic generator. The photovoltaic module is generally represented by an equivalent circuit whose parameters are experimentally calculated by using the characteristic current-tension, I-V. The precise determination of these parameters stays a challenge for the researchers, making to a big difference in the models and the digital methods dedicated to their characterizations. In the present paper, We are interested to characterize the parameters of single diode and two diodes models, in order to plan the behavior of the photovoltaic generator under real functioning conditions. We developed an identification method of the parameters using Newton Raphson method by using the software Matlab/Simulink. This method is the faster technique which allows the identification of several parameters and can be used in real time applications. The results of the proposed method show an accordance with the experimental and simulated characteristics of photovoltaic generator.展开更多
This paper presents an accurate small-signal model for multi-gate GaAs pHEMTs in switching-mode.The extraction method for the proposed model is developed.A 2-gate switch structure is fabricated on a commercial 0.5μm ...This paper presents an accurate small-signal model for multi-gate GaAs pHEMTs in switching-mode.The extraction method for the proposed model is developed.A 2-gate switch structure is fabricated on a commercial 0.5μm AlGaAs/GaAs pHEMT technology to verify the proposed model.Excellent agreement has been obtained between the measured and simulated results over a wide frequency range.展开更多
Parameter extraction is an important step for circuit simulation methods that are based on physical models of semiconductor devices. A novel physical parameter extraction approach for Schottky diodes is proposed in th...Parameter extraction is an important step for circuit simulation methods that are based on physical models of semiconductor devices. A novel physical parameter extraction approach for Schottky diodes is proposed in this paper. By employing a set of analytical formulas, this approach extracts all of the necessary physical parameters of the diode chip in a unique way. It then extracts the package parasitic parameters with a curve-fitting method. To validate the proposed approach, a model HSMS-282 c commercial Schottky diode is taken as an example. Its physical parameters are extracted and used to simulate the diode's electrical characteristics. The simulated results based on the extracted parameters are compared with the measurements and a good agreement is obtained, which verifies the feasibility and accuracy of the proposed approach.展开更多
Current transport mechanism in Ni-germanide/n-type Ge Schottky diodes is investigated using current-voltage characterisation technique with annealing temperatures from 300 ℃ to 500℃. Based on the current transport m...Current transport mechanism in Ni-germanide/n-type Ge Schottky diodes is investigated using current-voltage characterisation technique with annealing temperatures from 300 ℃ to 500℃. Based on the current transport model, a simple method to extract parameters of the NiGe/Ge diode is presented by using the I-V characteristics. Parameters of NiGe/n-type Ge Schottky diodes fabricated for testing in this paper are as follows: the ideality factor n, the series resistance Rs, the zero-field barrier height Фb0, the interface state density Dit, and the interracial layer capacitance Ci. It is found that the ideality factor n of the diode increases with the increase of annealing temperature. As the temperature increases, the interface defects from the sputtering damage and the penetration of metallic states into the Ge energy gap are passivated, thus improving the junction quality. However, the undesirable crystallisations of Ni-germanide are observed together with NiGe at a temperature higher than 400℃. Depositing a very thin (-1 nm) heavily Ge-doped n+ Ge intermediate layer can improve the NiGe film morphology significantly.展开更多
Particle swarm optimization(PSO) and invasive weed optimization(IWO) algorithms are used for extracting the modeling parameters of materials useful for optics and photonics research community. These two bio-inspired a...Particle swarm optimization(PSO) and invasive weed optimization(IWO) algorithms are used for extracting the modeling parameters of materials useful for optics and photonics research community. These two bio-inspired algorithms are used here for the first time in this particular field to the best of our knowledge. The algorithms are used for modeling graphene oxide and the performances of the two are compared. Two objective functions are used for different boundary values. Root mean square(RMS) deviation is determined and compared.展开更多
TiO2 thin films were deposited on glass substrates by sputtering in a conventional rf magnetron sputtering system. X-ray diffraction pattern and transmission spectrum were measured. The curves of refraction index and ...TiO2 thin films were deposited on glass substrates by sputtering in a conventional rf magnetron sputtering system. X-ray diffraction pattern and transmission spectrum were measured. The curves of refraction index and extinction coefficient distributions as well as the thickness of films calculated from transmission spectrum were obtained. The optimization problem was also solved using a method based on a constrained nonlinear programming algorithm.展开更多
An accurate and broad-band method for hetero-junction bipolar transistors(HBT) small-signal model parameters-extraction is presented in this paper. An equivalent circuit forthe HBT under a forward-bias condition is pr...An accurate and broad-band method for hetero-junction bipolar transistors(HBT) small-signal model parameters-extraction is presented in this paper. An equivalent circuit forthe HBT under a forward-bias condition is proposed for extraction of accessresistance and parasiticinductance. This method differs from previous ones by extracting the c-quivalent circuit parameterswithout using special test structure or global numerical optimization techniques. The mainadvantage of this method is that a unique and physically meaningful set of intrinsic parameters isextracted from impedance and admittance representation of the measured S-pa-rameters in thefrequency range of 1-12 GHz under different bias conditions. The method yields a deviation of lessthan 5% between measured and modeled S-parameters.展开更多
An improved parasitic parameter extraction method for InP high electron mobil-ity transistor(HEMT)is presented.Parasitic parameter extraction is the first step of model parameter extraction and its accuracy has a grea...An improved parasitic parameter extraction method for InP high electron mobil-ity transistor(HEMT)is presented.Parasitic parameter extraction is the first step of model parameter extraction and its accuracy has a great impact on the subsequent internal pa-rameter extraction.It is necessary to accurately determine and effectively eliminate the parasitic effect,so as to avoid the error propagation to the internal circuit parameters.In this paper,in order to obtain higher accuracy of parasitic parameters,parasitic parameters are extracted based on traditional analytical method and optimization algorithm to obtain the best parasitic parameters.The validity of the proposed parasitic parameter extraction method is verified with excellent agreement between the measured and modeled S-param-eters up to 40 GHz for InP HEMT.In 0.1-40 GHz InP HEMT,the average relative error of the optimization algorithm is about 9%higher than that of the analysis method,which verifies the validity of the parasitic parameter extraction method.The extraction of parasit-ic parameters not only provides a foundation for the high-precision extraction of small sig-nal intrinsic parameters of HEMT devices,but also lays a foundation for the high-preci-sion extraction of equivalent circuit model parameters of large signal and noise signals of HEMT devices.展开更多
Accurate PV system simulators are implemented with expensive software platforms using paid irradiance data.The main purpose of this paper is to develop and validate a PV system simulator,beginning with a solar cell pa...Accurate PV system simulators are implemented with expensive software platforms using paid irradiance data.The main purpose of this paper is to develop and validate a PV system simulator,beginning with a solar cell parameter extraction model,then test and validate long-termIrradiance data using free online source(Typical Meteorological Year TMY in(PVGIS)European website),and finally building full solar generator simulator to run in working real conditions.Comparing results with Accurate Paid PV simulators(which use theMuneer model)showed good accuracy of the proposed simulator.Work flow starts with the Irradiance model’s data processing,then solar cell 5 parameters model data processing(to extract cell parameters),and finally full system simulator.MATLAB coding programs in real working conditions are used for simulation.Results of solar cell parameter extraction show 99.6%to 99.99%matching with data sheet and cell performance under standard test conditions.Systemmodel simulation output shows 8%less yearly generated energy compared to the PVGIS 2022 long-term simulation(hourly basis(one-year time)).This is due to incident energy variations(between the years 2016 and 2022)of 4.02%.The novelty of the algorithm is the methodology,as it tests irradiance data on an hourly basis and validates results for a whole continuous year.Also,the 5-parameter solar cell model is used to be validated in long term analysis,not only STC conditions and could be applied on any PV solar cell.The algorithm and block diagramused are scalable,modular,and interchangeable with similarmodels to be tested.This simulator could test severalmethods andmodels in solar pv technology.展开更多
We design a hybrid integrated chaotic semiconductor laser with short-cavity optical feedback. It can be assembled in a commercial butterfly shell with just three micro-lenses. One of them is coated by a transflective ...We design a hybrid integrated chaotic semiconductor laser with short-cavity optical feedback. It can be assembled in a commercial butterfly shell with just three micro-lenses. One of them is coated by a transflective film to provide the optical feedback for chaos generation while insuring regular laser transmission. We prove the feasibility of the chaos generation in this compact structure and provide critical external parameters for the fabrication by theoretical simulations. Rather than the usual changeless internal parameters used in previous simulation research, we extract the real parameters of the chip by experiment. Moreover, the maps of the largest Lyapunov exponent with varying bias current and feedback intensity Kap demonstrate the dynamic characteristics under different external-cavity conditions. Each laser chip has its own optimal external cavity length(L) and feedback intensity(Kap) to generate chaos because of the different internal parameters. We have acquired two ranges of optimal parameters(L = 4 mm, 0.12 〈 Kap 〈 0.2 and L = 5 mm, 0.07 〈 Kap 〈 0.12) for two different chips.展开更多
Electrical characterization analyses are proposed in this work using the Lambert function on Schottky junctions in GaN wide band gap semiconductor devices for extraction of physical parameters.The Lambert function is ...Electrical characterization analyses are proposed in this work using the Lambert function on Schottky junctions in GaN wide band gap semiconductor devices for extraction of physical parameters.The Lambert function is used to give an explicit expression of the current in the Schottky junction.This function is applied with defined conduction phenomena,whereas other work presented arbitrary(or undefined)conduction mechanisms in such parameters' extractions.Based upon AlGaN/GaN HEMT structures,extractions of parameters are undergone in order to provide physical characteristics.This work highlights a new expression of current with defined conduction phenomena in order to quantify the physical properties of Schottky contacts in AlGaN/GaN HEMT transistors.展开更多
We present a convenient and practical electromagnetic(EM)assisted small-signal model extraction method for InP double-heterojunction bipolar transistors(DHBTs).Parasitic parameters of pad and electrode fingers are ext...We present a convenient and practical electromagnetic(EM)assisted small-signal model extraction method for InP double-heterojunction bipolar transistors(DHBTs).Parasitic parameters of pad and electrode fingers are extracted by means of 3D EM simulation.The simulations with a new excitation scheme are closer to the actual on-wafer measurement conditions.Appropriate simulation settings are calibrated by comparing measurement and simulation of OPEN and SHORT structures.A simplerπ-type topology is proposed for the intrinsic model,in which the base-collector resistance Rμ,output resistance Rce are deleted,and a capacitance Cce is introduced to characterize the capacitive parasitic caused by the collector finger and emitter ground bar.The intrinsic parameters are all extracted by exact equations that are derived from rigorous mathematics.The method is characterized by its ease of implementation and the explicit physical meaning of extraction procedure.Experimental validations are performed at four biases for three InGaAs/InP HBT devices with 0.8×7μm,0.8×10μm and 0.8×15μm emitter,and quite good fitting results are obtained in the range of 0.1-50 GHz.展开更多
Panicle swarm optimization (PSO) is an optimization algorithm based on the swarm intelligent principle. In this paper the modified PSO is applied to a kernel principal component analysis ( KPCA ) for an optimal ke...Panicle swarm optimization (PSO) is an optimization algorithm based on the swarm intelligent principle. In this paper the modified PSO is applied to a kernel principal component analysis ( KPCA ) for an optimal kernel function parameter. We first comprehensively considered within-class scatter and between-class scatter of the sample features. Then, the fitness function of an optimized kernel function parameter is constructed, and the particle swarm optimization algorithm with adaptive acceleration (CPSO) is applied to optimizing it. It is used for gearbox condi- tion recognition, and the result is compared with the recognized results based on principal component analysis (PCA). The results show that KPCA optimized by CPSO can effectively recognize fault conditions of the gearbox by reducing bind set-up of the kernel function parameter, and its results of fault recognition outperform those of PCA. We draw the conclusion that KPCA based on CPSO has an advantage in nonlinear feature extraction of mechanical failure, and is helpful for fault condition recognition of complicated machines.展开更多
Microwave-assisted extraction(MAE)technology was used to extract silymarin from milk thistle seeds.The single factor experiments and quadratic orthogonal rotation regression combination design were adopted to study th...Microwave-assisted extraction(MAE)technology was used to extract silymarin from milk thistle seeds.The single factor experiments and quadratic orthogonal rotation regression combination design were adopted to study the effects of such factors as extraction time,extraction temperature,ethanol concentration and solid-liquid ratio on silymarin yield.Ultraviolet-Visible(UV-Vis)spectrophotometry method was employed to measure the silybin content.The optimal technological conditions for extracting silymarin from milk thistle seeds by MAE were determined,and then the extraction regression mathematical model was established.The importance orders of factors that influenced the extraction yield within the experimental model were as follows:ethanol concentration,the ratio of solid to liquid,extraction temperature and extraction time.The optimum extraction parameters were obtained as follows:extraction time 50 min,extraction temperature 130℃,ethanol concentration 85%(V/V),solid to liquid ratio 1∶40(g/mL),and under such conditions,experimental value of silymarin yield after being extracted three times is 59.33mg/g.The validation experiments verify that the established regression mathematical model can predict the extraction yield of silymarin accurately.展开更多
This letter presents an approach based on differential evolution (DE) algorithm for determining the solar cell model parameters from current-voltage (I - V) characteristics. The validity of this approach has been ...This letter presents an approach based on differential evolution (DE) algorithm for determining the solar cell model parameters from current-voltage (I - V) characteristics. The validity of this approach has been confirmed with experimental and simulated I - V data. It was demonstrated that the I - V curve derived from the parameters extracted by the DE approach is in good agreement with the experimental or simulated I - V data. A low objective function value as well as a high parameter precision can be obtained by the DE algorithm.展开更多
文摘In this work,forward current voltage characteristics for multi-quantum wells Al_(0.33)Ga_(0.67)As Schottky diode were measured at temperature ranges from 100 to 300 K.The main parameters of this Schottky diode,such as the ideality factor,barrier height,series resistance and saturation current,have been extracted using both analytical and heuristics methods.Differential evolution(DE),particle swarm optimization(PSO)and artificial bee colony(ABC)have been chosen as candidate heuristics algorithms,while Cheung technic was selected as analytical extraction method.The obtained results show clearly the high performance of DE algorithms in terms of parameters accuracy,convergence speed and robustness.
文摘Extraction of accurate Photo Voltaic (PV) model parameters is a challenging task for PV simulator developers. To mitigate this challenging task a novel approach using Gravitational Search Algorithm (GSA) for accurate extraction of PV model parameters is proposed in this paper. GSA is a population based heuristic optimization method which depends on the law of gravity and mass interactions. In this optimization method, the searcher agents are collection of masses which interact with each other using laws of gravity and motion of Newton. The developed PV model utilizes mathematical equations and is described through an equivalent circuit model comprising of a current source, a diode, a series resistor and a shunt resistor including the effect of changes in solar irradiation and ambient temperature. The optimal values of photo-current, diode ideality factor, series resistance and shunt resistance of the developed PV model are obtained by using GSA. The simulations of the characteristic curves of PV modules (SM55, ST36 and ST40) are carried out using MATLAB/Simulink environment. Results obtained using GSA are compared with Differential Evolution (DE), which shows that GSA based parameters are better optimal when compared to DE.
文摘Several parameters of a commercial Si-based Schottky barrier diode (SBD) with unknown metal material and semiconductor-type have been investigated in this work from dark forward and reverse I-V characteristics in the temperature (T) range of [274.5 K - 366.5 K]. Those parameters include the reverse saturation current (I<sub>s</sub>), the ideality factor (n), the series and the shunt resistances (R<sub>s</sub> and R<sub>sh</sub>), the effective and the zero bias barrier heights (Φ<sub>B</sub> and Φ<sub>B0</sub>), the product of the electrical active area (A) and the effective Richardson constant (A**), the built-in potential (V<sub>bi</sub>), together with the semiconductor doping concentration (N<sub>A</sub> or N<sub>D</sub>). Some of them have been extracted by using two or three different methods. The main features of each approach have been clearly stated. From one parameter to another, results have been discussed in terms of structure performance, comparison on one another when extracted from different methods, accordance or discordance with data from other works, and parameter’s temperature or voltage dependence. A comparison of results on Φ<sub>B</sub>, ΦB0</sub>, n and N<sub>A</sub> or N<sub>D</sub> parameters with some available data in literature for the same parameters, has especially led to clear propositions on the identity of the analyzed SBD’s metal and semiconductor-type.
基金supported by the National Natural Science Foundation of China under Grant No.62001339.
文摘This paper proposes a design and fine-tuning method for mixed electric and magnetic coupling filters.It derives the quantitative relationship between the coupling coefficients(electric and magnetic coupling,i.e.,EC and MC)and the linear coefficients of frequencydependent coupling for the first time.Different from the parameter extraction technique using the bandpass circuit model,the proposed approach explicitly relatesEC and MC to the coupling matrix model.This paper provides a general theoretic framework for computer-aided design and tuning of a mixed electric and magnetic coupling filter based on coupling matrices.An example of a 7th-order coaxial combline filter design is given in the paper,verifying the practical value of the approach.
文摘An accurate and novel small-signal equivalent circuit model for GaN high-electron-mobility transistors(HEMTs)is proposed,which considers a dual-field-plate(FP)made up of a gate-FP and a source-FP.The equivalent circuit of the overall model is composed of parasitic elements,intrinsic transistors,gate-FP,and source-FP networks.The equivalent circuit of the gate-FP is identical to that of the intrinsic transistor.In order to simplify the complexity of the model,a series combination of a resistor and a capacitor is employed to represent the source-FP.The analytical extraction procedure of the model parameters is presented based on the proposed equivalent circuit.The verification is carried out on a 4×250μm GaN HEMT device with a gate-FP and a source-FP in a 0.45μm technology.Compared with the classic model,the proposed novel small-signal model shows closer agreement with measured S-parameters in the range of 1.0 to 18.0 GHz.
文摘The mathematical modeling of solar cells is essential for any optimization operation of the efficiency or the diagnosis of photovoltaic generator. The photovoltaic module is generally represented by an equivalent circuit whose parameters are experimentally calculated by using the characteristic current-tension, I-V. The precise determination of these parameters stays a challenge for the researchers, making to a big difference in the models and the digital methods dedicated to their characterizations. In the present paper, We are interested to characterize the parameters of single diode and two diodes models, in order to plan the behavior of the photovoltaic generator under real functioning conditions. We developed an identification method of the parameters using Newton Raphson method by using the software Matlab/Simulink. This method is the faster technique which allows the identification of several parameters and can be used in real time applications. The results of the proposed method show an accordance with the experimental and simulated characteristics of photovoltaic generator.
文摘This paper presents an accurate small-signal model for multi-gate GaAs pHEMTs in switching-mode.The extraction method for the proposed model is developed.A 2-gate switch structure is fabricated on a commercial 0.5μm AlGaAs/GaAs pHEMT technology to verify the proposed model.Excellent agreement has been obtained between the measured and simulated results over a wide frequency range.
基金Project supported by the Joint Fund of the National Natural Science Foundation of China and the China Academy of Engineering Physics(Grant No.U1230112)
文摘Parameter extraction is an important step for circuit simulation methods that are based on physical models of semiconductor devices. A novel physical parameter extraction approach for Schottky diodes is proposed in this paper. By employing a set of analytical formulas, this approach extracts all of the necessary physical parameters of the diode chip in a unique way. It then extracts the package parasitic parameters with a curve-fitting method. To validate the proposed approach, a model HSMS-282 c commercial Schottky diode is taken as an example. Its physical parameters are extracted and used to simulate the diode's electrical characteristics. The simulated results based on the extracted parameters are compared with the measurements and a good agreement is obtained, which verifies the feasibility and accuracy of the proposed approach.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60936005 and 60976068)the New Century Excellent Talents of Ministry of Education of China (Grant No. NCET-05-0851)+1 种基金the Cultivation Fund of Key Scientific and Technical Innovation Project,Ministry of Education of China (Grant No. 708083)the Applied Materials Innovation Fund(Grant No. XA-AM-200701)
文摘Current transport mechanism in Ni-germanide/n-type Ge Schottky diodes is investigated using current-voltage characterisation technique with annealing temperatures from 300 ℃ to 500℃. Based on the current transport model, a simple method to extract parameters of the NiGe/Ge diode is presented by using the I-V characteristics. Parameters of NiGe/n-type Ge Schottky diodes fabricated for testing in this paper are as follows: the ideality factor n, the series resistance Rs, the zero-field barrier height Фb0, the interface state density Dit, and the interracial layer capacitance Ci. It is found that the ideality factor n of the diode increases with the increase of annealing temperature. As the temperature increases, the interface defects from the sputtering damage and the penetration of metallic states into the Ge energy gap are passivated, thus improving the junction quality. However, the undesirable crystallisations of Ni-germanide are observed together with NiGe at a temperature higher than 400℃. Depositing a very thin (-1 nm) heavily Ge-doped n+ Ge intermediate layer can improve the NiGe film morphology significantly.
文摘Particle swarm optimization(PSO) and invasive weed optimization(IWO) algorithms are used for extracting the modeling parameters of materials useful for optics and photonics research community. These two bio-inspired algorithms are used here for the first time in this particular field to the best of our knowledge. The algorithms are used for modeling graphene oxide and the performances of the two are compared. Two objective functions are used for different boundary values. Root mean square(RMS) deviation is determined and compared.
文摘TiO2 thin films were deposited on glass substrates by sputtering in a conventional rf magnetron sputtering system. X-ray diffraction pattern and transmission spectrum were measured. The curves of refraction index and extinction coefficient distributions as well as the thickness of films calculated from transmission spectrum were obtained. The optimization problem was also solved using a method based on a constrained nonlinear programming algorithm.
基金Supported by the National Natural Science Foun dation of China(60444004) and the AM Foundation of Shanghai Mu nicipal Science and Technology Commission of China (0109)
文摘An accurate and broad-band method for hetero-junction bipolar transistors(HBT) small-signal model parameters-extraction is presented in this paper. An equivalent circuit forthe HBT under a forward-bias condition is proposed for extraction of accessresistance and parasiticinductance. This method differs from previous ones by extracting the c-quivalent circuit parameterswithout using special test structure or global numerical optimization techniques. The mainadvantage of this method is that a unique and physically meaningful set of intrinsic parameters isextracted from impedance and admittance representation of the measured S-pa-rameters in thefrequency range of 1-12 GHz under different bias conditions. The method yields a deviation of lessthan 5% between measured and modeled S-parameters.
文摘An improved parasitic parameter extraction method for InP high electron mobil-ity transistor(HEMT)is presented.Parasitic parameter extraction is the first step of model parameter extraction and its accuracy has a great impact on the subsequent internal pa-rameter extraction.It is necessary to accurately determine and effectively eliminate the parasitic effect,so as to avoid the error propagation to the internal circuit parameters.In this paper,in order to obtain higher accuracy of parasitic parameters,parasitic parameters are extracted based on traditional analytical method and optimization algorithm to obtain the best parasitic parameters.The validity of the proposed parasitic parameter extraction method is verified with excellent agreement between the measured and modeled S-param-eters up to 40 GHz for InP HEMT.In 0.1-40 GHz InP HEMT,the average relative error of the optimization algorithm is about 9%higher than that of the analysis method,which verifies the validity of the parasitic parameter extraction method.The extraction of parasit-ic parameters not only provides a foundation for the high-precision extraction of small sig-nal intrinsic parameters of HEMT devices,but also lays a foundation for the high-preci-sion extraction of equivalent circuit model parameters of large signal and noise signals of HEMT devices.
文摘Accurate PV system simulators are implemented with expensive software platforms using paid irradiance data.The main purpose of this paper is to develop and validate a PV system simulator,beginning with a solar cell parameter extraction model,then test and validate long-termIrradiance data using free online source(Typical Meteorological Year TMY in(PVGIS)European website),and finally building full solar generator simulator to run in working real conditions.Comparing results with Accurate Paid PV simulators(which use theMuneer model)showed good accuracy of the proposed simulator.Work flow starts with the Irradiance model’s data processing,then solar cell 5 parameters model data processing(to extract cell parameters),and finally full system simulator.MATLAB coding programs in real working conditions are used for simulation.Results of solar cell parameter extraction show 99.6%to 99.99%matching with data sheet and cell performance under standard test conditions.Systemmodel simulation output shows 8%less yearly generated energy compared to the PVGIS 2022 long-term simulation(hourly basis(one-year time)).This is due to incident energy variations(between the years 2016 and 2022)of 4.02%.The novelty of the algorithm is the methodology,as it tests irradiance data on an hourly basis and validates results for a whole continuous year.Also,the 5-parameter solar cell model is used to be validated in long term analysis,not only STC conditions and could be applied on any PV solar cell.The algorithm and block diagramused are scalable,modular,and interchangeable with similarmodels to be tested.This simulator could test severalmethods andmodels in solar pv technology.
基金Project supported by the International Science and Technology Cooperation Program of China(Grant No.2014DFA50870)the National Natural Science Foundation of China(Grant Nos.61377089,61475111,and 61527819)+4 种基金Shanxi Province Natural Science Foundation,China(Grant No.2015011049)Shanxi Province Youth Science and Technology Foundation,China(Grant No.201601D021069)Shanxi Scholarship Council of China(Grant No.2016-036)Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi,ChinaProgram for Sanjin Scholar,China
文摘We design a hybrid integrated chaotic semiconductor laser with short-cavity optical feedback. It can be assembled in a commercial butterfly shell with just three micro-lenses. One of them is coated by a transflective film to provide the optical feedback for chaos generation while insuring regular laser transmission. We prove the feasibility of the chaos generation in this compact structure and provide critical external parameters for the fabrication by theoretical simulations. Rather than the usual changeless internal parameters used in previous simulation research, we extract the real parameters of the chip by experiment. Moreover, the maps of the largest Lyapunov exponent with varying bias current and feedback intensity Kap demonstrate the dynamic characteristics under different external-cavity conditions. Each laser chip has its own optimal external cavity length(L) and feedback intensity(Kap) to generate chaos because of the different internal parameters. We have acquired two ranges of optimal parameters(L = 4 mm, 0.12 〈 Kap 〈 0.2 and L = 5 mm, 0.07 〈 Kap 〈 0.12) for two different chips.
基金Project supported by the French Department of Defense(DGA)
文摘Electrical characterization analyses are proposed in this work using the Lambert function on Schottky junctions in GaN wide band gap semiconductor devices for extraction of physical parameters.The Lambert function is used to give an explicit expression of the current in the Schottky junction.This function is applied with defined conduction phenomena,whereas other work presented arbitrary(or undefined)conduction mechanisms in such parameters' extractions.Based upon AlGaN/GaN HEMT structures,extractions of parameters are undergone in order to provide physical characteristics.This work highlights a new expression of current with defined conduction phenomena in order to quantify the physical properties of Schottky contacts in AlGaN/GaN HEMT transistors.
文摘We present a convenient and practical electromagnetic(EM)assisted small-signal model extraction method for InP double-heterojunction bipolar transistors(DHBTs).Parasitic parameters of pad and electrode fingers are extracted by means of 3D EM simulation.The simulations with a new excitation scheme are closer to the actual on-wafer measurement conditions.Appropriate simulation settings are calibrated by comparing measurement and simulation of OPEN and SHORT structures.A simplerπ-type topology is proposed for the intrinsic model,in which the base-collector resistance Rμ,output resistance Rce are deleted,and a capacitance Cce is introduced to characterize the capacitive parasitic caused by the collector finger and emitter ground bar.The intrinsic parameters are all extracted by exact equations that are derived from rigorous mathematics.The method is characterized by its ease of implementation and the explicit physical meaning of extraction procedure.Experimental validations are performed at four biases for three InGaAs/InP HBT devices with 0.8×7μm,0.8×10μm and 0.8×15μm emitter,and quite good fitting results are obtained in the range of 0.1-50 GHz.
基金supported by National Natural Science Foundation under Grant No.50875247Shanxi Province Natural Science Foundation under Grant No.2009011026-1
文摘Panicle swarm optimization (PSO) is an optimization algorithm based on the swarm intelligent principle. In this paper the modified PSO is applied to a kernel principal component analysis ( KPCA ) for an optimal kernel function parameter. We first comprehensively considered within-class scatter and between-class scatter of the sample features. Then, the fitness function of an optimized kernel function parameter is constructed, and the particle swarm optimization algorithm with adaptive acceleration (CPSO) is applied to optimizing it. It is used for gearbox condi- tion recognition, and the result is compared with the recognized results based on principal component analysis (PCA). The results show that KPCA optimized by CPSO can effectively recognize fault conditions of the gearbox by reducing bind set-up of the kernel function parameter, and its results of fault recognition outperform those of PCA. We draw the conclusion that KPCA based on CPSO has an advantage in nonlinear feature extraction of mechanical failure, and is helpful for fault condition recognition of complicated machines.
文摘Microwave-assisted extraction(MAE)technology was used to extract silymarin from milk thistle seeds.The single factor experiments and quadratic orthogonal rotation regression combination design were adopted to study the effects of such factors as extraction time,extraction temperature,ethanol concentration and solid-liquid ratio on silymarin yield.Ultraviolet-Visible(UV-Vis)spectrophotometry method was employed to measure the silybin content.The optimal technological conditions for extracting silymarin from milk thistle seeds by MAE were determined,and then the extraction regression mathematical model was established.The importance orders of factors that influenced the extraction yield within the experimental model were as follows:ethanol concentration,the ratio of solid to liquid,extraction temperature and extraction time.The optimum extraction parameters were obtained as follows:extraction time 50 min,extraction temperature 130℃,ethanol concentration 85%(V/V),solid to liquid ratio 1∶40(g/mL),and under such conditions,experimental value of silymarin yield after being extracted three times is 59.33mg/g.The validation experiments verify that the established regression mathematical model can predict the extraction yield of silymarin accurately.
基金supported by the National Natural Science Foundation of China under Grant No.51305407
文摘This letter presents an approach based on differential evolution (DE) algorithm for determining the solar cell model parameters from current-voltage (I - V) characteristics. The validity of this approach has been confirmed with experimental and simulated I - V data. It was demonstrated that the I - V curve derived from the parameters extracted by the DE approach is in good agreement with the experimental or simulated I - V data. A low objective function value as well as a high parameter precision can be obtained by the DE algorithm.