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Appraising the bandgap energy of materials is a major issue in the field of band engineering. To better understand the behavior of GaAs1-uNu material, it is necessary to improve the applied calculation methodologies. The band anticrossing model (BAC) allows modeling of the bandgap energy when diluted nitrogen is incorporated into the material. The model can be improved using artificial neural networks (ANN) as an alternative solution, which is rarely applied. Our goal is to study the efficiency of the (ANN) method to gauge the bandgap energy of the material from experimental measurements, considering the extensive strain due to the lattice mismatch between the substrate and the material. This makes the GaAsN material controllable with (ANN) method, and is a potential candidate for the fabrication of ultrafast optical sensors.

In this paper, the CuInGaSe 2 based solar cell optimization has been established. We have simulated the structural strain effect. The effect of gallium concentration on the optical properties and the quantum external efficiency EQE was investigated. We also optimized the concentration x at low defect densities. The optimal gallium concentration is 0.30. We obtained an efficiency of the CuIn 0.70 Ga 0.30 Se 2 absorber solar cell around 24% with a strain ɛ = 0.64% and material defects densities equal to 1.2x1015cm−3. This work has been validated by theoretical and experimental studies. This study allows us to find a compromise between concentration x and defect concentrations in order to improve the performance and high efficiency of the solar cell. • The effect of structural deformation has been studied and simulated. • The effect of gallium on the optical properties and EQE was investigated. • We optimized the x concentration at low defect concentrations. • An efficiency of the solar cell which is equal to 24% with ɛ = 0.6% was obtained. • This work is validated by a theoretical and experimental study. [ABSTRACT FROM AUTHOR]

This study aims to investigate the different optical properties of the ZnSnN 2 absorber layer such as absorption, reflection and transmission coefficients. The effects of the ZnSnN 2 absorber layer thickness, temperature,and defect density on electrical parameters such as short circuit current density, open circuit voltage, fill factor and efficiency have also been studied in detail. These factors play an important role in the performance of the ZnO/CdS/ZnSnN 2 /Si/Mo structure. The highest efficiency of about 23.32 % is achieved without defects in the ZnSnN 2 absorber layer, under the 1-sun AM1.5 solar spectrum, by applying the flat band condition and considering the strain values of 0.37 % (ZnSnN 2 /Cds) and 7.17 % (ZnSnN 2 /Si). In addition to high efficiency, the ZnSnN 2 has a high absorption coefficient. This device will play a crucial role in optoelectronic applications. This structure is a promising candidate for low cost and high efficiency photovoltaic technology. [ABSTRACT FROM AUTHOR]

This work presents electrical simulations and the optimization of the device structure ITO/PEDOT:PSS/PTB7:PC70BM/Al, using OghmaNano (Organic and hybrid Material Nano) software. The result analysis was given at different layer thickness and the best performance characteristics are obtained at 250 nm of the active layer. Then, the simulated results of different parameters such as charge carrier mobility, temperature and series resistance are investigated. Different structures of organic solar cells, the role of the interface layer used as a hole transport layer and the effect of electrodes are discussed. Finally, the energy level of the device is explained by the optical simulation and the optimized solar cell was proposed. [ABSTRACT FROM AUTHOR]

A combination of a Copper Indium Gallium Selenide (CIGS) and Silicon (Si) layer has been recognized as an excellent choice for producing heterojunction based solar cells with improved efficiency and low cost processing techniques. The quaternary compound CIGS and silicon (Si) regions exhibit a lattice mismatch of about 5%, which induces a strain and impacts the electronic characteristics of the CIGS/Si heterojunction solar cell. A new viewpoint suggests the integration of a silicon germanium (Si 1-y Ge y) layer in the CIGS/Si region to reduce the impact of lattice mismatch. The objective of this study is to investigate how different gallium and germanium concentrations (x Ga and y Ge) affect the following factors: lattice mismatch (ε) , critical thickness (h c) and absorption coefficient (α)of CIGS/SiGe based solar cells. It also aims to analyze how these concentrations impact the primary parameters used to evaluate solar cell performance such as external quantum efficiency, short circuit current density, fill factor, open circuit voltage and conversion efficiency. The simulation results agree well with the existing theoretical and experimental literature data, confirming the suitability of the physical characteristics employed in this numerical study. By tuning the concentrations of Gallium and Germanium, it is feasible to attain an efficiency of 24% owing to the lattice compensation phenomenon in Si 1-y Ge y layers. These findings hold significant implications for the development and advancement of solar cell technology, as well as for enhancing their conversion efficiency and commercialization. • A strain-compensated CIGS/Si structure was achieved by adding SiGe layer. • The incorporation of SiGe improves the absorbance and EQE of the CIGS solar cell. • The improvement of the solar performances of the CIGS is ensured by the SiGe layer. • Optimizing Ga, Ge concentrations makes it possible to achieve an efficiency of 24%. [ABSTRACT FROM AUTHOR]

The aim of this modeling and simulation is to study the influence of the incorporation of nitrogen (N) and aluminum (Al) on the optoelectronic properties of the structure Al x Ga 1-x As 1-y N y /Ge, and then choose the right combination (N, Al) which gives us a better conversational efficiency of the junction(Al x Ga 1-x As 1-y N y /Ge), in this study, we simulated the effect of N and Al on the strain, the band gap, carrier mobility and structure efficiency where we based on theoretical models experimentally validate, It has been shown that the Al concentration slightly affects the stress and the band gap, but it has a significant influence on the incorporation of nitrogen and in a more homogeneous way introducing a dramatic decrease in the band gap what change considerably the absorption, carrier mobility and final yield of the structure. [ABSTRACT FROM AUTHOR]

The electrical properties of InAsP/Si quantum dot solar cell (QDSC) are numerically studied and analyzed in this paper. Many effects like number of quantum dot (QD) layers inserted and Arsenic content of InAs x P 1-x on photovoltaic properties such as current density-voltage J-V and the external quantum efficiency (EQE) are investigated. Our results have been shown that the optimal Arsenic content is 0.6. With 30 InAsP/Si QDs layers, relative enhancements of about 7% and 6.70% of short-circuit current and efficiency are achieved, respectively. Otherwise, the absorption range edge of low energy photons was extended from 1120 to 1200 nm. This reveals that introduction of QDs in the intrinsic region of p -i- n Silicon (Si) solar cell enhances significantly the device characteristics beyond what has been reported for conventional semiconductor-based solar cells. [ABSTRACT FROM AUTHOR]

This work deals with the modeling and optimization of the CuInGaSe/CdS based structure for photovoltaic applications. We took into consideration the effect of the gallium concentration and the temperature on the strain, band gap energy, absorption and efficiency of the structure. It has been demonstrated that increasing the gallium concentration increases the ban gap energy, while increasing temperature decreases it. These two parameters vary the efficiency significantly. For x = 30% and T = 300 K, the band gap energy is equal to 1.15 eV with a deformation of 0.5% and efficiency around 20%. We have also found that at this value of the band gap energy the structure absorbs most of the incident photons. Then to achieve a reliable cell based on CuInGaSe/CdS it is adequate to find a compromise between the gallium concentration in the alloy, the temperature and the strain. [ABSTRACT FROM AUTHOR]

In this paper, we report a theoretical investigation of bandgap properties of GaAsNBi based materials on GaAs substrates. We look at the influence of nitrogen (N) and bismuth (Bi) concentrations on the position of conduction and valence bands; and we show that a split of the conduction band can take place with the incorporation of N at 5% under level, while a split of the valence band of both heavy and light holes sub-bands takes place after the incorporation of Bi at 14% under level. In order to compute the transition energies, we used the VBCA k.p 16×16 model. The N and Bi concentrations effects as well as the lattice mismatch value have also been taken into account. For a couple of N and Bi concentrations of 3% and 6%, we found strained gap energy around 0.68 eV. Furthermore, we have also shown that the absorption coefficient increases significantly when the N and Bi concentrations increase. [ABSTRACT FROM AUTHOR]

In this paper, we report a simulation and investigation of a single In x Ga 1-x N/GaN axial multiple quantum well nanowire (MQWNW) solar cell of radius r = 190 nm and a length of L = 1165 nm. Our results have been shown that 15 In 0.15 Ga 0.85 N (QW) /GaN (barrier) periods is the maximum number that our structure can be supported with an optimal efficiency of about 1.65% achieved with ε = 1.5%. The insertion of MQWs in nanowire permits the growth of In x Ga 1-x N MQWs with high indium concentration of about 50% and ε = 5%. At this indium concentration, the optimal efficiency obtained was 1.70%. Moreover; the structure has been studied with respect to the nanowire radius. In this context, we have shown that the efficiency enhancement achieved through the increase of radius is attributed to the increase of photo-carriers. Study of polarization and proton irradiations has indicated the negative effect of polarization on structure performances and high resistance of III-N semiconductor materials against the radiations, respectively. From these novel structures we can improve solar cell performance for new applications. [ABSTRACT FROM AUTHOR]

This paper describes a numerical study of ultrathin CIGS solar cell using the one-dimensional simulation program. The various properties of the absorber layer such as the band gap energy, the absorption coefficient, and the reflection coefficient are investigated. In addition, the impact of adding silicon to reduce the thickness of CIGS is also examined. We have carried out a theoretical study to show the influence of the thickness and the gallium concentration of the CIGS absorber layer on the performance of the Mo/Si/CIGS/ZnS/ZnO structure. It has been demonstrated that increasing x Ga and d CIGS affect the conversion efficiency, FF, V oc, and J sc. Finally, we have achieved a conversion efficiency η = 21.08% with an optimal value of gallium content equal to 20%when the thickness of the absorber layer has been reduced to 0.75 μm. This study allowed us to improve the performance of thin film solar cell. • The impact of material properties on solar cell performance. • The effect of Ga content and CIGS thickness on the conversion efficiency. • Ultrathin CIGS solar cell performance when adding a silicon layer. • The influence of defects and R s on the different electrical parameters. [ABSTRACT FROM AUTHOR]