abderrahmane belghachi - Academia.edu (original) (raw)

Papers by abderrahmane belghachi

SPIE Proceedings, 2008

ABSTRACT This paper summarizes the electrical and thermal characterizations of thin film PV modul... more ABSTRACT This paper summarizes the electrical and thermal characterizations of thin film PV modules based on amorphous triple junctions (3J: a-Si) and Copper Indium Selenide (CIS) thin film solar cells. Tests are operated in outdoor exposure and under natural sunlight of Ghardaia (Algeria) as specific desert climate environment, characterized by high irradiation and temperature levels. Data acquired from Environmental Operating Conditions (EOC) was converted into solar module output characteristics at Standard Test Conditions (STC) by using three method suggested by Anderson and Mermoud as well as the equations already standardized as IEC 60891. Then, based on the investigation results of the conversion equations, differences among the converting methods (range of application, specificity of solar cell material, and experimental test conditions) were studied.

Desalination, 2007

The objective of this work is to understand the physical and chemical properties of the standard ... more The objective of this work is to understand the physical and chemical properties of the standard cure copolymer ethylene-vinyl-acetate (EVA), used as encapsulant, during photovoltaic module encapsulation process and also in field exposure of Algerian Sahara as specific desert climate. EVA samples are characterized by gel content measurements (crosslinking test), dielectric spectroscopy as function of temperature and frequency, thermally stimulated current (TSC), UV-visible-near infrared transmittance spectrometry to detect the quality of the material. Results show a decrease in most properties of EVA in natural field exposure due principally to the specificity of the region characterised by hot and dry climate.

Microelectronics Journal, 2005

To investigate perimeter recombination current in heteroface GaAs solar cells, two models were pr... more To investigate perimeter recombination current in heteroface GaAs solar cells, two models were proposed; the first concerned the analysis of recombination at the surface that intersects the space-charge layer and the second dealt with recombination at the quasi-neutral region. Recombination at the depleted layer surface has a 2kT character and was treated in a similar way to that of the bulk, using the model of Sah, Noyce and Shockley. The electric field at the surface due to Fermi level pinning is different from that of the bulk. We suggested a simple model to obtain an analytical form of the perimeter current at the space-charge region surface that yielded values of the product of the characteristic length by the surface recombination velocity (L s S 0) that agreed well with experimental values. The recombination current outside the space-region is of two dimensional nature and has a kT behaviour, the model adopted consisted mainly of solving numerically the bidimensional continuity equation. An effective recombination velocity was introduced to account for bend bending caused by the charged surface states. As the ratio of perimeter to area (P/A) is increased the perimeter current acquired significant proportions, thus the expected 2kT current due to bulk deep levels existing in the depletion layer is two to three orders of magnitude too small to account for.

Journal of Nanoelectronics and Optoelectronics, 2017

Journal of Nanoelectronics and Optoelectronics, 2015

Journal of Physics: Condensed Matter, 2009

In this paper, we report a detailed numerical study of the electron irradiation effect on the pho... more In this paper, we report a detailed numerical study of the electron irradiation effect on the photoelectrical parameters of a GaAs based p(+)-n-n(+) solar cell which operates under an AM0 solar spectrum. As a consequence of irradiation different types of defects are created in the semiconductor lattice. These defects introduce energy levels in the gap of the material. The majority of studies dealing with irradiation-induced degradation in solar cells relate it mainly to recombination centres, which are deep levels lying near the mid gap. In the present study, numerical simulation is used to demonstrate that the irradiation-induced degradation is not solely due to recombination centres. Other less deep levels, or traps, play a major role in this degradation. When only recombination centres are taken into account, the short circuit current density (J(sc)) is hardly affected while the other cell output parameters such as the open circuit voltage (V(oc)), the conversion efficiency (η) and the fill factor (FF) are strongly deteriorated. However, if less deep levels or traps are taken into account together with recombination centres, J(sc) becomes sensitive to electron irradiation and the other output parameter deteriorations become less sensitive.

In this paper, we analyze the problem of quasiballistic electron transport in ultra small of merc... more In this paper, we analyze the problem of quasiballistic electron transport in ultra small of mercury -cadmiumtelluride (Hg0.8Cd0.2Te -MCT) n+-n- n+ devices from hydrodynamic point view. From our study, we note that, when the size of the active layer is low than 0.1μm and for low bias application( ( ≥ 9mV), the quasi-ballistic transport has an important effect.

Cu(In,Ga)Se2 thin films have been deposited using a three stage process on several substrate mate... more Cu(In,Ga)Se2 thin films have been deposited using a three stage process on several substrate materials (glass and metallic foils), with CdS and In2S3 buffer layers, showing and efficiency of 13 % on the average. The objective of this work is to study and understand the origin of defects present in these cells and their effect on the internal operation of the device. Therefore, we investigate series of devices that differ in the absorber stoichiometry, the type of buffer and substrate and also the buffer preparation method. The characterization of the devices concentrates on the analysis of the admittance spectroscopy (AS) and deep-level transient spectroscopy (DLTS) spectra, in an attempt to present an understanding of defect affecting the capacitance characteristic of the CIGSe solar cells and their performance.

International Journal of Smart Grid and Clean Energy, 2020

Effects of electron irradiation-induced deep level defects have been studied on both n/p and p/n ... more Effects of electron irradiation-induced deep level defects have been studied on both n/p and p/n Indium Phosphide (InP) solar cells with very thin emitters. The simulation results reveal that the n/p structure offers a somewhat better short-circuit current and that the p/n structure renders an improved open-circuit voltage, not only before electron irradiation but also after 1 MeV electron irradiation with 5×10 15 electrons per cm 2 fluence. Further, the calculated findings highlight that the n/p solar cell structure is more resistant than that of a p/n structure.

Tandem solar cells have demonstrated the potential to increase the efficiency of solar energy con... more Tandem solar cells have demonstrated the potential to increase the efficiency of solar energy conversion. The detailed balance principle introduced by Shockley and Queisser 1961 was later applied by De Vos 1980 to study the tandem structures. Although the mathematical formulation is simple, the mathematical resolution is rather complex but fairly accurate. In this work I describe a simple Monte Carlo (MC) technique to determine the detailed balance limiting efficiency for tandem solar cell stacks. This statistical method used a simple sampling scheme which is adequate to resolve a complex equation system that is depicting a large number of multi‐junction without any further approximations. In current‐matched tandem solar cells, the band gap of each sub‐cell has to be chosen so that the current flowing through each of the sub‐cells is the same. Finding from this study fcus on10 stacked junctions; the algorithm can be applied to a larger number of sub‐cells. The simulation is carried ...

Zeitschrift für Naturforschung A, 2018

Structural arrangement and construction are the keys to electron/hole motion through organic semi... more Structural arrangement and construction are the keys to electron/hole motion through organic semiconductor lattices. In this work, we focused on the disorder energy, temperature, and electric field effects on charge carrier mobilities using a Poole–Frenkel mobility model for SubPc/C60 devices. The results agree with those found in the literature. We observed important temperature, applied voltage, and disorder energy dependencies of the current-voltage characteristics and charge carrier mobilities; these characteristics have the Gunn curve form called negative conductivity, which has been reported in amorphous semiconductors.

Optik, 2017

Recent development in band-gap engineering technology has lead researches in the field of tandem ... more Recent development in band-gap engineering technology has lead researches in the field of tandem photovoltaic solar cells to examine the feasibility of low-dimensional multi-junction solar cell. This is achieved by the combination of only two materials with different band-gaps, piled vertically with different thicknesses. It is theoretically possible to tailor a set of effective band-gaps responding to the requirement of tandem solar cells with a maximum efficiency. In the present work we investigate the potential of tandem solar cells based on GaPAs/GaInAs multiple quantum well structure. Efficiency limit has been previously calculated using the detailed balance principle for multi-junction solar cells. Adjusting the number of wells and their widths and barrier depth gives the possibility of varying the effective band-gap. Numerical resolution of Schrodinger equation for GaPAs/GaInAs multiple quantum well demonstrates the potential of this III-V compound to achieve a wide range of effective band-gaps varying from 2.27 to 0.70 eV. However, this material could be used to manufacture low-dimensional tandem solar cells and can achieve tandem solar cells up to six sub-cells, that can yield an efficiency limit up to 59% for series constrained AM 1.5 global radiation.

Sciences Technologie a, Dec 22, 2004

In the present work we report results of the simulation of transport phenomena in InP under unifo... more In the present work we report results of the simulation of transport phenomena in InP under uniform electric fields in both transient and steady state regimes using semi-classical Ensemble Monte Carlo method (EMC). The EMC algorithm used consists mainly of the simulation of an ensemble of carriers and follows their history in parallel for a sequences of very short time intervals in three dimensional momentum and real spaces. After each sampling interval, data (drift velocity, energy…) is collected for each particle and the values are averaged. In our simulation an ensemble of 10 5 electrons are used. The program was written with Fortran 90 language and run on IBM PC(PIII, 800GHz). The obtained results are in good agreement with reported experimental data.

Energy Procedia, 2012

The fact that laser diodes are by nature a key component of all optoelectronic systems induced du... more The fact that laser diodes are by nature a key component of all optoelectronic systems induced during ten last years a particularly great research effort is devoted to this component. Corresponding works cover a broad field of study of the physical properties of materials up to the analysis of the whole of the mechanisms governing the device operation. The aim of the present work is to contribute by a comparison of lasers diode containing quaternary alloy for different wavelength for a structure hetero-junction and double hetero-junction. We chose for our study the following alloys:

2013 International Renewable and Sustainable Energy Conference (IRSEC), 2013

ABSTRACT In conventional Cadmium telluride (CdTe) solar cells cadmium sulfide (CdS) layer is used... more ABSTRACT In conventional Cadmium telluride (CdTe) solar cells cadmium sulfide (CdS) layer is used as emitter window, the choice proved to be appropriate because of its large energy band gap 2.42 eV and its lattice parameter fits well with CdTe. The inconvenience of this window is its important absorption coefficient in the bleu region. To surmount this problem one of the suggested solutions is to use a much wider energy band gap window layer with suitable parameters onto the CdS layer, or replace the CdS layer with a suitable window. In the present work we investigate the effect of Cd1-xZnxS ternary compound window on the top of the p-CdTe cell. The calculations and the analysis are carried out using SCAPS 1D numerical simulator. In this study we deal with two configurations the first structure comprises a double window (Cd1-xZnxS /CdS) and the second incorporates a simple (Cd1-xZnxS) window. When x is reduced from 0.08 to 0.05 in the second structure, the energy conversion efficiency increases from 17.11 to 21.15 %. While the best obtained energy conversion efficiency of the first structure is about 16.04 % only.

2013 International Renewable and Sustainable Energy Conference (IRSEC), 2013

ABSTRACT Losses in solar cells are major concern for photovoltaic designers and minimizing them i... more ABSTRACT Losses in solar cells are major concern for photovoltaic designers and minimizing them is the aim of all workers in this field. Recombination of photo generated charge carriers, both in the bulk and at surfaces, is the most prominent loss mechanism. In this work, surface recombination effect on crystalline silicon solar cells, both at the front and rear sides, is investigated. For typical thin silicon solar cell (100μm) the rear surface recombination is more important than the front. This could be treated by reducing rear surface metallization coverage or of a BSF layer while the front recombination could be reduced by surface passivation.

Journal of Physics: Conference Series, 2015

The critical factor that limits the efficiencies of organic electronic devices is the low charge ... more The critical factor that limits the efficiencies of organic electronic devices is the low charge carrier mobility which is attributed to disorder in organic films. In this context, we have studied the effects of disorder on carrier mobility in organic Schottky diode of electrons for the fullerene (C 60). Our results show that the mobility is sensitive probes of structural phase transitions and order-disorder underlying C 60. Where it is one reason behind the low mobility which it take as value 1.4x10-2 cm 2 /V.s above critical temperature Tc =289K.

Energy Procedia, 2015

In this work we have studied the potential energy of the fullerene molecule which is an organic s... more In this work we have studied the potential energy of the fullerene molecule which is an organic semiconductor. In this context, the stretching, the bending, the torsion energy and The Van der Waals energy are investigated carefully. The best state of charge carrier's transport is when energy becomes maximal. So, the stretching energy takes the value 6.13 eV, the bending energy takes the values 11.24 eV and 1.25 eV and the torsion energy takes the value 0.35 eV. Our results are in a good agreement with those extracted from literature.

2015 International Conference on Noise and Fluctuations (ICNF), 2015

We propose an hydrodynamic approach for the calculation of the small-signal equivalent elements o... more We propose an hydrodynamic approach for the calculation of the small-signal equivalent elements of InGaAs HEMTs. The values of the different elements are calculated from the Y parameters of the intrinsic HEMT and are obtained from the Fourier analysis of the device transient response to voltage-step perturbations at the drain and gate electrodes. For low biases and for frequencies up to 100 GHz, the values of the intrinsic elements are independent of the frequency in the whole range of device operation. However, for frequencies higher than 100 GHz, the transconductance, the conductance and the gate-drain capacity depend on frequency due to the presence of non-stationary dynamic phenomena in the HEMT channel.

Solar Cells - New Approaches and Reviews, 2015

SPIE Proceedings, 2008

ABSTRACT This paper summarizes the electrical and thermal characterizations of thin film PV modul... more ABSTRACT This paper summarizes the electrical and thermal characterizations of thin film PV modules based on amorphous triple junctions (3J: a-Si) and Copper Indium Selenide (CIS) thin film solar cells. Tests are operated in outdoor exposure and under natural sunlight of Ghardaia (Algeria) as specific desert climate environment, characterized by high irradiation and temperature levels. Data acquired from Environmental Operating Conditions (EOC) was converted into solar module output characteristics at Standard Test Conditions (STC) by using three method suggested by Anderson and Mermoud as well as the equations already standardized as IEC 60891. Then, based on the investigation results of the conversion equations, differences among the converting methods (range of application, specificity of solar cell material, and experimental test conditions) were studied.

Desalination, 2007

The objective of this work is to understand the physical and chemical properties of the standard ... more The objective of this work is to understand the physical and chemical properties of the standard cure copolymer ethylene-vinyl-acetate (EVA), used as encapsulant, during photovoltaic module encapsulation process and also in field exposure of Algerian Sahara as specific desert climate. EVA samples are characterized by gel content measurements (crosslinking test), dielectric spectroscopy as function of temperature and frequency, thermally stimulated current (TSC), UV-visible-near infrared transmittance spectrometry to detect the quality of the material. Results show a decrease in most properties of EVA in natural field exposure due principally to the specificity of the region characterised by hot and dry climate.

Microelectronics Journal, 2005

To investigate perimeter recombination current in heteroface GaAs solar cells, two models were pr... more To investigate perimeter recombination current in heteroface GaAs solar cells, two models were proposed; the first concerned the analysis of recombination at the surface that intersects the space-charge layer and the second dealt with recombination at the quasi-neutral region. Recombination at the depleted layer surface has a 2kT character and was treated in a similar way to that of the bulk, using the model of Sah, Noyce and Shockley. The electric field at the surface due to Fermi level pinning is different from that of the bulk. We suggested a simple model to obtain an analytical form of the perimeter current at the space-charge region surface that yielded values of the product of the characteristic length by the surface recombination velocity (L s S 0) that agreed well with experimental values. The recombination current outside the space-region is of two dimensional nature and has a kT behaviour, the model adopted consisted mainly of solving numerically the bidimensional continuity equation. An effective recombination velocity was introduced to account for bend bending caused by the charged surface states. As the ratio of perimeter to area (P/A) is increased the perimeter current acquired significant proportions, thus the expected 2kT current due to bulk deep levels existing in the depletion layer is two to three orders of magnitude too small to account for.

Journal of Nanoelectronics and Optoelectronics, 2017

Journal of Nanoelectronics and Optoelectronics, 2015

Journal of Physics: Condensed Matter, 2009

In this paper, we report a detailed numerical study of the electron irradiation effect on the pho... more In this paper, we report a detailed numerical study of the electron irradiation effect on the photoelectrical parameters of a GaAs based p(+)-n-n(+) solar cell which operates under an AM0 solar spectrum. As a consequence of irradiation different types of defects are created in the semiconductor lattice. These defects introduce energy levels in the gap of the material. The majority of studies dealing with irradiation-induced degradation in solar cells relate it mainly to recombination centres, which are deep levels lying near the mid gap. In the present study, numerical simulation is used to demonstrate that the irradiation-induced degradation is not solely due to recombination centres. Other less deep levels, or traps, play a major role in this degradation. When only recombination centres are taken into account, the short circuit current density (J(sc)) is hardly affected while the other cell output parameters such as the open circuit voltage (V(oc)), the conversion efficiency (η) and the fill factor (FF) are strongly deteriorated. However, if less deep levels or traps are taken into account together with recombination centres, J(sc) becomes sensitive to electron irradiation and the other output parameter deteriorations become less sensitive.

In this paper, we analyze the problem of quasiballistic electron transport in ultra small of merc... more In this paper, we analyze the problem of quasiballistic electron transport in ultra small of mercury -cadmiumtelluride (Hg0.8Cd0.2Te -MCT) n+-n- n+ devices from hydrodynamic point view. From our study, we note that, when the size of the active layer is low than 0.1μm and for low bias application( ( ≥ 9mV), the quasi-ballistic transport has an important effect.

Cu(In,Ga)Se2 thin films have been deposited using a three stage process on several substrate mate... more Cu(In,Ga)Se2 thin films have been deposited using a three stage process on several substrate materials (glass and metallic foils), with CdS and In2S3 buffer layers, showing and efficiency of 13 % on the average. The objective of this work is to study and understand the origin of defects present in these cells and their effect on the internal operation of the device. Therefore, we investigate series of devices that differ in the absorber stoichiometry, the type of buffer and substrate and also the buffer preparation method. The characterization of the devices concentrates on the analysis of the admittance spectroscopy (AS) and deep-level transient spectroscopy (DLTS) spectra, in an attempt to present an understanding of defect affecting the capacitance characteristic of the CIGSe solar cells and their performance.

International Journal of Smart Grid and Clean Energy, 2020

Effects of electron irradiation-induced deep level defects have been studied on both n/p and p/n ... more Effects of electron irradiation-induced deep level defects have been studied on both n/p and p/n Indium Phosphide (InP) solar cells with very thin emitters. The simulation results reveal that the n/p structure offers a somewhat better short-circuit current and that the p/n structure renders an improved open-circuit voltage, not only before electron irradiation but also after 1 MeV electron irradiation with 5×10 15 electrons per cm 2 fluence. Further, the calculated findings highlight that the n/p solar cell structure is more resistant than that of a p/n structure.

Tandem solar cells have demonstrated the potential to increase the efficiency of solar energy con... more Tandem solar cells have demonstrated the potential to increase the efficiency of solar energy conversion. The detailed balance principle introduced by Shockley and Queisser 1961 was later applied by De Vos 1980 to study the tandem structures. Although the mathematical formulation is simple, the mathematical resolution is rather complex but fairly accurate. In this work I describe a simple Monte Carlo (MC) technique to determine the detailed balance limiting efficiency for tandem solar cell stacks. This statistical method used a simple sampling scheme which is adequate to resolve a complex equation system that is depicting a large number of multi‐junction without any further approximations. In current‐matched tandem solar cells, the band gap of each sub‐cell has to be chosen so that the current flowing through each of the sub‐cells is the same. Finding from this study fcus on10 stacked junctions; the algorithm can be applied to a larger number of sub‐cells. The simulation is carried ...

Zeitschrift für Naturforschung A, 2018

Structural arrangement and construction are the keys to electron/hole motion through organic semi... more Structural arrangement and construction are the keys to electron/hole motion through organic semiconductor lattices. In this work, we focused on the disorder energy, temperature, and electric field effects on charge carrier mobilities using a Poole–Frenkel mobility model for SubPc/C60 devices. The results agree with those found in the literature. We observed important temperature, applied voltage, and disorder energy dependencies of the current-voltage characteristics and charge carrier mobilities; these characteristics have the Gunn curve form called negative conductivity, which has been reported in amorphous semiconductors.

Optik, 2017

Recent development in band-gap engineering technology has lead researches in the field of tandem ... more Recent development in band-gap engineering technology has lead researches in the field of tandem photovoltaic solar cells to examine the feasibility of low-dimensional multi-junction solar cell. This is achieved by the combination of only two materials with different band-gaps, piled vertically with different thicknesses. It is theoretically possible to tailor a set of effective band-gaps responding to the requirement of tandem solar cells with a maximum efficiency. In the present work we investigate the potential of tandem solar cells based on GaPAs/GaInAs multiple quantum well structure. Efficiency limit has been previously calculated using the detailed balance principle for multi-junction solar cells. Adjusting the number of wells and their widths and barrier depth gives the possibility of varying the effective band-gap. Numerical resolution of Schrodinger equation for GaPAs/GaInAs multiple quantum well demonstrates the potential of this III-V compound to achieve a wide range of effective band-gaps varying from 2.27 to 0.70 eV. However, this material could be used to manufacture low-dimensional tandem solar cells and can achieve tandem solar cells up to six sub-cells, that can yield an efficiency limit up to 59% for series constrained AM 1.5 global radiation.

Sciences Technologie a, Dec 22, 2004

In the present work we report results of the simulation of transport phenomena in InP under unifo... more In the present work we report results of the simulation of transport phenomena in InP under uniform electric fields in both transient and steady state regimes using semi-classical Ensemble Monte Carlo method (EMC). The EMC algorithm used consists mainly of the simulation of an ensemble of carriers and follows their history in parallel for a sequences of very short time intervals in three dimensional momentum and real spaces. After each sampling interval, data (drift velocity, energy…) is collected for each particle and the values are averaged. In our simulation an ensemble of 10 5 electrons are used. The program was written with Fortran 90 language and run on IBM PC(PIII, 800GHz). The obtained results are in good agreement with reported experimental data.

Energy Procedia, 2012

The fact that laser diodes are by nature a key component of all optoelectronic systems induced du... more The fact that laser diodes are by nature a key component of all optoelectronic systems induced during ten last years a particularly great research effort is devoted to this component. Corresponding works cover a broad field of study of the physical properties of materials up to the analysis of the whole of the mechanisms governing the device operation. The aim of the present work is to contribute by a comparison of lasers diode containing quaternary alloy for different wavelength for a structure hetero-junction and double hetero-junction. We chose for our study the following alloys:

2013 International Renewable and Sustainable Energy Conference (IRSEC), 2013

ABSTRACT In conventional Cadmium telluride (CdTe) solar cells cadmium sulfide (CdS) layer is used... more ABSTRACT In conventional Cadmium telluride (CdTe) solar cells cadmium sulfide (CdS) layer is used as emitter window, the choice proved to be appropriate because of its large energy band gap 2.42 eV and its lattice parameter fits well with CdTe. The inconvenience of this window is its important absorption coefficient in the bleu region. To surmount this problem one of the suggested solutions is to use a much wider energy band gap window layer with suitable parameters onto the CdS layer, or replace the CdS layer with a suitable window. In the present work we investigate the effect of Cd1-xZnxS ternary compound window on the top of the p-CdTe cell. The calculations and the analysis are carried out using SCAPS 1D numerical simulator. In this study we deal with two configurations the first structure comprises a double window (Cd1-xZnxS /CdS) and the second incorporates a simple (Cd1-xZnxS) window. When x is reduced from 0.08 to 0.05 in the second structure, the energy conversion efficiency increases from 17.11 to 21.15 %. While the best obtained energy conversion efficiency of the first structure is about 16.04 % only.

2013 International Renewable and Sustainable Energy Conference (IRSEC), 2013

ABSTRACT Losses in solar cells are major concern for photovoltaic designers and minimizing them i... more ABSTRACT Losses in solar cells are major concern for photovoltaic designers and minimizing them is the aim of all workers in this field. Recombination of photo generated charge carriers, both in the bulk and at surfaces, is the most prominent loss mechanism. In this work, surface recombination effect on crystalline silicon solar cells, both at the front and rear sides, is investigated. For typical thin silicon solar cell (100μm) the rear surface recombination is more important than the front. This could be treated by reducing rear surface metallization coverage or of a BSF layer while the front recombination could be reduced by surface passivation.

Journal of Physics: Conference Series, 2015

The critical factor that limits the efficiencies of organic electronic devices is the low charge ... more The critical factor that limits the efficiencies of organic electronic devices is the low charge carrier mobility which is attributed to disorder in organic films. In this context, we have studied the effects of disorder on carrier mobility in organic Schottky diode of electrons for the fullerene (C 60). Our results show that the mobility is sensitive probes of structural phase transitions and order-disorder underlying C 60. Where it is one reason behind the low mobility which it take as value 1.4x10-2 cm 2 /V.s above critical temperature Tc =289K.

Energy Procedia, 2015

In this work we have studied the potential energy of the fullerene molecule which is an organic s... more In this work we have studied the potential energy of the fullerene molecule which is an organic semiconductor. In this context, the stretching, the bending, the torsion energy and The Van der Waals energy are investigated carefully. The best state of charge carrier's transport is when energy becomes maximal. So, the stretching energy takes the value 6.13 eV, the bending energy takes the values 11.24 eV and 1.25 eV and the torsion energy takes the value 0.35 eV. Our results are in a good agreement with those extracted from literature.

2015 International Conference on Noise and Fluctuations (ICNF), 2015

We propose an hydrodynamic approach for the calculation of the small-signal equivalent elements o... more We propose an hydrodynamic approach for the calculation of the small-signal equivalent elements of InGaAs HEMTs. The values of the different elements are calculated from the Y parameters of the intrinsic HEMT and are obtained from the Fourier analysis of the device transient response to voltage-step perturbations at the drain and gate electrodes. For low biases and for frequencies up to 100 GHz, the values of the intrinsic elements are independent of the frequency in the whole range of device operation. However, for frequencies higher than 100 GHz, the transconductance, the conductance and the gate-drain capacity depend on frequency due to the presence of non-stationary dynamic phenomena in the HEMT channel.

Solar Cells - New Approaches and Reviews, 2015