Browsing by Author "Alshammari, Mohammad T"

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Analysis of Hybrid Hetero-Homo Junction Lead-Free Perovskite Solar Cells by SCAPS Simulator
(MDPI, 09/12/2021) Salem, Marwa. S; Shaker, Ahmed; Zekry, Abdelhalim; Abouelatta, Mohamed; Alanazi, Adwan; Alshammari, Mohammad T; Gontand, Christian
In this work, we report on the effect of substituting the active intrinsic i-layer on a conventional pin structure of lead-free perovskite solar cell (PSC) by a homo p-n junction, keeping the thickness of the active layer constant. It is expected that when the active i-layer is substituted by a p-n homo junction, one can increase the collection efficiency of the photo-generated electrons and holes due to the built-in electric field of the homo junction. The impact of the technological and physical device parameters on the performance parameters of the solar cell have been worked out. It was found that p-side thickness must be wider than the n-side, while its acceptor concentration should be slightly lower than the donor concentration of the n-side to achieve maximum efficiency. In addition, different absorber types, namely, i-absorber, n-absorber and p-absorber, are compared to the proposed pn-absorber, showing a performance-boosting effect when using the latter. Moreover, the proposed structure is made without a hole transport layer (HTL) to avoid the organic issues of the HTL materials. The back metal work function, bulk trap density and ETL material are optimized for best performance of the HTL-free structure, giving Jsc = 26.48, Voc = 0.948 V, FF = 77.20 and PCE = 19.37% for AM1.5 solar spectra. Such results highlight the prospective of the proposed structure and emphasize the importance of using HTL-free solar cells without deteriorating the efficiency. The solar cell is investigated by using SCAPS simulator.
Bandwidth Broadening of Piezoelectric Energy Harvesters Using Arrays of a Proposed Piezoelectric Cantilever Structure
(MDPI AG, 8/17/2021) Salem, Marwa S; Ahmed, Shimaa; Shaker, Ahmed; Alshammari, Mohammad T; Al-Dhlan, Kawther A; Alanazi, Adwan; Saeed, Ahmed; Abouelatta, Mohamed
One of the most important challenges in the design of the piezoelectric energy harvester is its narrow bandwidth. Most of the input vibration sources are exposed to frequency variation during their operation. The piezoelectric energy harvester’s narrow bandwidth makes it difficult for the harvester to track the variations of the input vibration source frequency. Thus, the harvester’s output power and overall performance is expected to decline from the designed value. This current study aims to solve the problem of the piezoelectric energy harvester’s narrow bandwidth. The main objective is to achieve bandwidth broadening which is carried out by segmenting the piezoelectric material of the energy harvester into n segments; where n could be more than one. Three arrays with two, four, and six beams are shaped with two piezoelectric segments. The effect of changing the length of the piezoelectric material segment on the resonant frequency, output power, and bandwidth, as well as the frequency response is investigated. The proposed piezoelectric energy harvesters were implemented utilizing a finite element method (FEM) simulation in a MATLAB environment. The results show that increasing the number of array beams increases the output power and bandwidth. For the three-beam arrays, at n equals 2, 6 mW output power and a 9 Hz bandwidth were obtained. Moreover, the bandwidth of such arrays covered around 5% deviation from its resonant frequency. All structures were designed to operate as a steel wheel safety sensor which could be used in train tracks. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Influence of base doping level on the npn microstructure solar cell performance: A TCAD study
(Elsevier B.V., 2021-11) Salem, Marwa; Zekry, A; Abouelatta, M; Alshammari, Mohammad T; Alanazi, Adwan; Al-Dhlan, Kawther A; A.Shaker, A
Optical Materials Volume 121, November 2021, 111501 Short Communication Influence of base doping level on the npn microstructure solar cell performance: A TCAD study Author links open overlay panelMarwaSalemabA.ZekrycM.AbouelattacMohammad T.AlshammaridAdwanAlanazidKawther A.Al-DhlandA.Shakere a Department of Computer Engineering, Computer Science and Engineering College, University of Ha'il, Ha'il, Saudi Arabia b Department of Electrical Communication and Electronics Systems Engineering, Faculty of Engineering, Modern Science and Arts University (MSA), Cairo, Egypt c Department of Electronics and Communications, Faculty of Engineering, Ain Shams University, Cairo, Egypt d Department of Computer science and information, Computer Science and Engineering College, University of Ha'il, Ha'il, Saudi Arabia e Department of Engineering Physics and Mathematics, Faculty of Engineering, Ain Shams University, Cairo, Egypt Received 5 April 2021, Revised 16 August 2021, Accepted 18 August 2021, Available online 24 August 2021. crossmark-logo https://doi.org/10.1016/j.optmat.2021.111501 Get rights and content Highlights • Device simulation of proposed npn microstructure solar cell was comprehensively performed. • The impact of base high doping on the device performance was fully discussed. • The results show that for NB ranging from 5 × 1017 cm−3 to 2 × 1019 cm−3, the cell could achieve a competitive efficiency, from 15.4% to 9%, respectively. • For base doping ranging from 5×1017 cm-3 to 2×1019 cm-3, a competitive efficiency is 15.4% to 9%, respectively. Abstract Silicon industry has a mature learning curve which is the driver for 90% share of the PV market. Yet, the cost/m2 of the planar crystalline silicon solar cell is still high. To reduce the cost of silicon-based solar cells, heavily doped wafers can be used in a proposed npn microstructure in which photoexcited carries are vertically generated while the collection of carriers is accomplished in the lateral direction. In this work, we report on the influence of the heavily p + base doping concentration, Na, on the performance of the cell for different base widths. All simulations are performed by using SILVACO TCAD under AM1.5 illumination. The results show that for Na extending from 5 × 1017 cm−3 to 2 × 1019 cm−3, the cell could achieve a competitive efficiency, from 15.4% to 9%, respectively.
Narrowband Near-Infrared Perovskite/Organic Photodetector: TCAD Numerical Simulation
(Multidisciplinary Digital Publishing Institute (MDPI), 2022-07) Salem, Marwa S; Shaker, Ahmed; Al-Bagawia, Amal H; Aleid, Ghada Mohamed; Othman, Mohamed S; Alshammari, Mohammad T; Fedawy, Mostafa
Narrowband photodetectors (PD) established in the near-infrared (NIR) wavelength range are highly required in a variety of applications including high-quality bioimaging. In this simulation study, we propose a filter-less narrowband PD based on the architecture of perovskite/organic het- erojunction. The most decisive part of the photodetector is the hierarchical configuration of a larger bandgap perovskite material with a thicker film followed by a lower bandgap organic material with a narrower layer. The design of the structure is carried out by TCAD numerical simulations. Our structure is based on an experimentally validated wideband organic PD, which is modified by invok- ing an additional perovskite layer having a tunable bandgap. The main detector device comprises of ITO/perovskite (CsyFA1−yPb(IxBr1−x)3 )/organic blend (PBDTTT-c:C60-PCBM)/PEDOT:PSS/Al. The simulation results show that the proposed heterojunction PD achieves satisfactory performance when the thickness of perovskite and organic layers are 2.5 µm and 500 nm, respectively. The designed photodetector achieves a narrow spectral response at 730 nm with a full width at half-maximum (FWHM) of 33 nm in the detector, while having a responsivity of about 0.12 A/W at zero bias. The presented heterojunction perovskite/organic PD can efficiently detect light in the wavelength range of 700 to 900 nm. These simulation results can be employed to drive the development of filter-less narrowband NIR heterojunction PD.
On the Investigation of Interface Defects of Solar Cells: Lead-based vs Lead-free Perovskite
(IEEE Access, 2021) Salem, Marwa. S; Salah, Mostafa M; Mousa, Mohamed; Shaker, Ahmed; Zekry, Abdelhalim; Abouelatta, Mohamed; Alshammari, Mohammad T; Al-Dhlan, Kawther A; Gontrand, Christian
Perovskite solar cells (PSCs) have drawn significant consideration as a competing solar cell technology because of the drastic advance in their power conversion efficiency (PCE) over the last two decades. The interfaces between the electron transport layer (ETL) and the absorber layer and between the absorber layer and the hole transport layer (HTL) have a major impact on the performance of the PSCs. In this paper, we have investigated the defect interfaces between ETL/absorber layer and absorber layer/HTL of calibrated experimental lead-based and lead-free PSCs. The influence of the defect interfaces is studied in order to find the optimum value for the maximum possible PCE. While the PCE has not been enhanced considerably for the lead-based, it is boosted from 1.76% to 5.35% for lead-free PSCs. Also, bulk traps were found to have minor role in comparison with interface traps for the lead-free cell while they have a significant impact for the lead-based cell. The results presented in this work would shed some light on designing interface defects of various types of practical PSC structures and demonstrates the crucial impact of the interface defects on lead-free vs lead-based PSCs. All simulation studies are performed by using SCAPS-1D simulator.
Performance Improvement of npn Solar Cell Microstructure by TCAD Simulation: Role of Emitter Contact and ARC
(Multidisciplinary Digital Publishing Institute (MDPI), 2022-09) Marwa S, Salem; Zekry, Abdelhalim; Shaker, Ahmed; Abouelatta, Mohamed; Almurayziq, Tariq S; Alshammari, Mohammad T; El-Banna, Mohamed M
In the current study, the performance of the npn solar cell (SC) microstructure is improved by inspecting some modifications to provide possible paths for fabrication techniques of the structure. The npn microstructure is simulated by applying a process simulator by starting with a heavily doped p-type substrate which could be based on low-cost Si wafers. After etching deep notches through the substrate and forming the emitter by n-type diffusion, an aluminum layer is deposited to form the emitter electrode with about 0.1 µm thickness; thereby, the notches are partially filled. This nearly-open-notches microstructure, using thin metal instead of filling the notch completely with Al, gives an efficiency of 15.3%, which is higher than the conventional structure by 0.8%. Moreover, as antireflection coating (ARC) techniques play a crucial role in decreasing the front surface reflectivity, we apply different ARC schemes to inspect their influence on the optical performance. The influence of utilizing single layer (ZnO), double (Si3N4/ZnO), and triple (SiO2/Si3N/ZnO) ARC systems is investigated, and the simulation results are compared. The improvement in the structure performance because of the inclusion of ARC is evaluated by the relative change in the efficiency (∆η). In the single, double, and triple ARC, ∆η is found to be 12.5%, 15.4%, and 17%, respectively. All simulations are performed by using a full TCAD process and device simulators under AM1.5 illumination.
Performance Investigation of a Proposed Flipped npn Microstructure Silicon Solar Cell Using TCAD Simulation
(Multidisciplinary Digital Publishing Institute (MDPI), 2022-07) Salem, Marwa S; Zekry, Abdelhalim; Shaker, Ahmed; Abouelatta, Mohamed; ElBanna, Mohamed M; Almurayziq, Tariq S; Ramadan, Rabie A; Alshammari, Mohammad T
This work aims at inspecting the device operation and performance of a novel flipped npn microstructure solar cell based on low-cost heavily doped silicon wafers. The flipped structure was designed to eliminate the shadowing effect as applied in the conventional silicon-based interdigitated back-contact cell (IBC). Due to the disappearance of the shadowing impact, the optical performance and short-circuit current density of the structure have been improved. Accordingly, the cell power conversion efficiency (PCE) has been improved in comparison to the conventional npn solar cell microstructure. A detailed analysis of the flipped npn structure was carried out in which we per- formed TCAD simulations for the electrical and optical performance of the flipped cell. Additionally, a comparison between the presented flipped microstructure and the conventional npn solar cell was accomplished. The PCE of the conventional npn structure was found to be 14.5%, while it was about 15% for the flipped structure when using the same cell physical parameters. Furthermore, the surface recombination velocity and base bulk lifetime, which are the most important recombination parameters, were studied to investigate their influence on the flipped microstructure performance. An efficiency of up to 16% could be reached when some design parameters were properly fine-tuned. Moreover, the impact of the different physical models on the performance of the proposed cell was studied, and it was revealed that band gap narrowing effect was the most significant factor limiting the open-circuit voltage. All the simulations accomplished in this analysis were carried out using the SILVACO TCAD process and device simulators.
Prospective efficiency boosting of full-inorganic single-junction Sb2(S, Se)3 solar cell
(Elsevier BV, 2022-09) Salem, Marwa S; Shaker, Ahmed; Almurayziq, Tariq S; Alshammari, Mohammad T
Antimony selenosulfide, Sb2(S, Se)3, is regarded as an appropriate absorber to be utilized in terrestrial single junction solar cell applications thanks to the tunability of its bandgap energy which could be adjusted around 1.3 eV. To enhance the power conversion efficiency (PCE) of Sb2(S, Se)3-based single junction solar cell, we propose some design recommendations by using device simulation. First, in order to validate the simulation model, a calibration step is accomplished by comparing the numerical simulation results with those of a fabricated cell structure consisting of Au/Sb2(S, Se)3/CdS/ITO. The designed cell is formed without an organic hole transport layer (HTL) which, generally, harmfully affects the cell by causing stability issues. Next, we investigate the impact of the conduction band offset (CBO) between the electron transport layer (ETL) and the Sb2(S, Se)3 absorber utilizing the bandgap tunable material Cd1-xZnxS to achieve the optimum CBO. Various key design parameters for the presented cell such as the back contact work function as well as absorber thickness and doping concentration are also inspected. It is found that the most crucial parameter that affects the cell performance is the CBO which could be adjusted by modifying the Zn fraction in the ternary compound Cd1-xZnxS. Moreover, a study on the impact of the interface and bulk defects on device performance is carried out. The simulations, conducted in this study, are accomplished by SCAPS-1D simulator at 300 K temperature and under AM1.5G illumination.