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Effects of Multifunctional Interlayers on the Performance of Perovskite Solar Cells

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Effects of Multifunctional Interlayers on the Performance of...

International Conference on electrical, computer and Communication engineering (ECCE)

作者： Md. Seium Mahtab Dipto Md Jahirul Islam Md Rejvi Kaysir Javid Atai Department of Materials Science and Engineering (MSE) Khulna University of Engineering & Technology (KUET) Khulna Bangladesh Department of Electrical and Electronic Engineering (EEE) Khulna University of Engineering & Technology (KUET) Khulna 9203 Bangladesh Department of Electrical and Computer Engineering Waterloo Institute for Nanotechnology University of Waterloo Waterloo ON Canada School of Electrical and Information Engineering The University of Sydney NSW Australia

The development of perovskite solar cell (PSC) is one of the major advances in photovoltaic technology in recent years due to its lower cost, simple fabrication process, lightweight, sustainability, and being environmentally friendly. However, the power conversion efficiency (PCE) of the conventional PSC is still lower for commercialization. The efficiency of PSC has increased from 5% to 25% within the past few years, where introducing interlayer shows a significant improvement in PCE. In this paper, we numerically investigate the effects of different combinations of interlayers on the performance of PSC using gpvdm simulation software. Three different PCEs of 28.08%, 17.89 % and 25.62 % are found for three different interlayer combinations i.e., (i) Model A (TIO 2 /PMMA), (ii) Model B (V 2 O 5 /PEDOTPSS) and (iii) Model C (P3HT/ spiroMeOTAD). Both optical and electrical characteristics of different interlayers-based PSCs are investigated by using the properties of different interlayer materials in the simulation. Additionally, the photon distribution, their absorption, and consequent charge carrier generation are investigated while modifying the layer thickness of each unit. This study could be helpful for optimizing the electron and hole transport materials-based interlayers of the PSC.

关键词： Photovoltaic cells Optical device fabrication Charge carrier processes Electron optics Perovskites Software Optical materials

High Quality Factor Microcavity for Van der Waals Semiconductor Polaritons Using a Transferrable Mirror( vol 11 , 2201440 , 2023 )

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ADVANCED OPTICAL materials 2023年第23期11卷

作者： Paik, Eunice Y. Zhang, Long Hou, Shaocong Zhao, Haonan Chou, Yu-Hsun Forrest, Stephen R. Deng, Hui Department of Physics University of Michigan Ann Arbor Michigan USA Department of Physics University of Michigan Ann Arbor Michigan USA Department of Physics Xiamen University Xiamen China School of Electrical Engineering and Automation Wuhan University Wuhan China Department of Electrical and Computer Engineering University of Michigan Ann Arbor Michigan USA Department of Photonics National Cheng Kung University Tainan City Taiwan Departments of Electrical and Computer Engineering Physics and Materials Science and Engineering University of Michigan Ann Arbor Michigan USA

Semiconductor microcavities with a high quality‐factor are an important component for photonics research and technology, especially in the strong coupling regime. While van der Waals semiconductors have emerged as an interesting platform for photonics due to their strong exciton–photon interaction strength and engineering flexibility, incorporating them in photonic devices requires heterogeneous integration and remains a challenge. This study demonstrates a method to assemble high quality factor microcavities for van der Waals materials, using high reflectance top mirrors which, similar to van der Waals materials themselves, can be nondestructively and reliably peeled off the substrate and transferred onto the rest of the device. Microcavities are created with quality factors consistently above 2000 and up to 11000 ± 800; and the strong coupling regime is demonstrated. The method can be generalized to other types of heterogeneously integrated photonic structures and will facilitate research on cavity quantum electrodynamic and photonic systems using van der Waals materials.

关键词： distributed Bragg reflectors exciton–polaritons microcavity transition metal dichalcogenides van der Waals materials

Giant spin Hall effect with multi-directional spin components in Ni4W

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arXiv 2024年

作者： Yang, Yifei Lee, Seungjun Chen, Yu-Chia Jia, Qi Sousa, Duarte Odlyzko, Michael Garcia-Barriocanal, Javier Yu, Guichuan Haugstad, Greg Fan, Yihong Huang, Yu-Han Lyu, Deyuan Cresswell, Zach Low, Tony Wang, Jian-Ping Department of Electrical and Computer Engineering University of Minnesota MinneapolisMN55455 United States Characterization Facility University of Minnesota MinneapolisMN55455 United States Department of Chemical Engineering and Materials Science University of Minnesota MinneapolisMN55455 United States

Spin-orbit torque (SOT) can be used to efficiently manipulate the magnetic state of magnetic materials, which is an essential element for memory and logic applications. Due to symmetry constraints, only in-plane spins can be injected into the ferromagnet from the underlying SOT layer for conventional SOT materials such as heavy metals and topological materials. Through the use of materials with low symmetries, or other symmetry breaking approaches, unconventional spin currents with out-of-plane polarization has been demonstrated and enabled field-free deterministic switching of perpendicular magnetization. Despite this progress, the SOT efficiency of these materials has typically remained low. Here, we report a giant SOT efficiency of 0.85 in sputtered Ni4W/CoFeB heterostructure at room temperature, as evaluated by second harmonic Hall measurements. In addition, due to the low crystal symmetry of Ni4W, unconventional out-of-plane and Dresselhaus-like spin components were observed. Macro-spin simulation suggests our spin Hall tensor to provide about an order of magnitude improvement in the magnetization switching efficiency, thus broadening the path towards energy efficient spintronic devices using low-symmetry materials. Copyright © 2024, The Authors. All rights reserved.

关键词： Spin Hall effect

Electronic structure of InSb (001), (110), and (111)B surfaces

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arXiv 2023年

作者： Dong, Jason T. Inbar, Hadass S. Pendharkar, Mihir van Schijndel, Teun A.J. Young, Elliot C. Dempsey, Connor P. Palmstrøm, Christopher J. Materials Department University of California Santa BarbaraCA93106 United States Department of Electrical and Computer Engineering University of California Santa BarbaraCA93106 United States Department of Materials Science and Engineering Stanford University StanfordCA94305 United States

The electronic structure of various (001), (110), and (111)B surfaces of n-type InSb were studied with scanning tunneling microscopy and spectroscopy. The InSb(111)B (3x1) surface reconstruction is determined to be a disordered (111)B (3x3) surface reconstruction. The surface Fermi-level of the In rich and the equal In:Sb (001), (110), and (111)B surface reconstructions was observed to be pinned near the valence band edge. This observed pinning is consistent with a charge neutrality level lying near the valence band maximum. Sb termination was observed to shift the surface Fermi-level position by up to 254 ± 35 meV towards the conduction band on the InSb (001) surface and 60 ± 35 meV towards the conduction band on the InSb(111)B surface. The surface Sb on the (001) can shift the surface from electron depletion to electron accumulation. We propose the shift in the Fermi-level pinning is due to charge transfer from Sb clusters on the Sb terminated surfaces. Additionally, many sub-gap states were observed for the (111)B (3x1) surface, which are attributed to the disordered nature of this surface. This work demonstrates the tuning of the Fermi-level pinning position of InSb surfaces with Sb termination. Copyright © 2023, The Authors. All rights reserved.

关键词： Electronic structure

Heterostructure and Interfacial engineering for Low-Resistance Contacts to Ultra-Wide Bandgap AlGaN

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arXiv 2024年

作者： Zhu, Yinxuan Allerman, Andrew A. Joishi, Chandan Pratt, Jonathan Merwin Xavier, Agnes Maneesha Dominic Ortiz, Gabriel Calderon Klein, Brianna A. Armstrong, Andrew Hwang, Jinwoo Rajan, Siddharth Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States Sandia National Laboratories AlbuquerqueNM87123 United States

We report on the heterostructure and interfacial engineering of metalorganic chemical vapor deposition (MOCVD) grown reverse-graded contacts to ultra-wide bandgap AlGaN. A record low contact resistivity of 1.4 x 10-6 Ω.cm2 was reported on an Al0.82Ga0.18N metal semiconductor field effect transistor (MESFET) by compositionally grading the contact layer from Al0.85Ga0.15N → Al0.14Ga0.86N with degenerate doping and proper interfacial engineering considering bandgap-narrowing-induced band offset between channel and contact layer. This represents orders-of-magnitude of lower contact resistivity than that obtained in similar MOCVD-grown structures. A detailed, layer-by-layer analysis of the reverse graded contact and TCAD simulation of the bandgap narrowing effect highlighted that the reverse graded contact layer itself is extremely conductive and interfacial resistance due to bandgap-narrowing-induced barrier between contact and channel dominates the contact resistance. Copyright © 2024, The Authors. All rights reserved.

关键词： Aluminum gallium nitride

Special Issue on Advanced materials and Sensing Technologies on IoT Applications: Part 4-3 Preface

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Sensors and materials 2022年第7期34卷

作者： Meen, Teen-Hang Zhao, Wenbing Yang, Cheng-Fu Department of Electronic Engineering National Formosa University Taiwan Department of Electrical Engineering and Computer Science Cleveland State University United States Department of Chemical and Materials Engineering National University of Kaohsiung Taiwan

Utilizing (Al,Ga)2O3/Ga2O3 superlattices to measure cation vacancy diffusion and vacancy-concentration-dependent diffusion of Al, Sn, and Fe in β-Ga2O3

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arXiv 2024年

作者： Rock, Nathan D. Yang, Haobo Eisner, Brian Levin, Aviva Bhattacharyya, Arkka Krishnamoorthy, Sriram Ranga, Praneeth Walker, Michael A. Wang, Larry Cheng, Ming Kit Zhao, Wei Scarpulla, Michael A. Department of Materials Science and Engineering University of Utah Salt Lake CityUT84112 United States Department of Electrical and Computer Engineering University of Utah Salt Lake CityUT84112 United States Materials Department University of California Santa Barbara Santa BarbaraCA93106 United States Department of Metallurgical and Materials Engineering Colorado School of Mines GoldenCO80401 United States Eurofins EAG Material Science SunnyvaleCA94086 United States

Diffusion of native defects such as vacancies and their interactions with impurities are fundamental in semiconductor crystal growth, device processing, and long-term aging of equilibration and transient diffusion of vacancies are rarely investigated. We used (AlxGa1−x)2O3/Ga2O3 superlattices (SLs) to detect and analyze transient diffusion of cation vacancies during annealing in O2 at 1000 − 1100◦C. Using a novel finite difference scheme for the diffusion equation with time- and space-varying diffusion constant, we extract diffusion constants for Al, Fe, and cation vacancies under the given conditions, including the vacancy concentration dependence for Al. In the case of SLs grown on Sn-doped β − Ga2O3 (010) substrates, gradients observed in the extent of Al diffusion indicate that vacancies present in the substrate transiently diffuse through the SLs, interacting with Sn as it also diffuses. In the case of SLs grown on (010) Fe-doped substrates, the Al diffusion is uniform through the SLs, indicating a depth-uniform concentration of vacancies. We find no evidence in either case for the introduction of VGa from the free surface at rates sufficient to affect Al diffusion down to ppm concentrations, which has important bearing on the validity of typically-made assumptions of vacancy equilibration. Additionally, we show that unintentional impurities in Sn-doped Ga2O3 such as Fe, Ni, Mn, Cu, and Li also diffuse towards the surface and accumulate. Many of these likely have fast interstitial diffusion modes capable of destabilizing devices over time, thus highlighting the importance of controlling unintentional impurities in β − Ga2O3 wafers. Copyright © 2024, The Authors. All rights reserved.

关键词： Gallium compounds

Thermal Annealing and Radiation Effects on Structural and electrical Properties of NbN/GaN Superconductor/Semiconductor Junction

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arXiv 2025年

作者： Margiotta, Stephen Liu, Binzhi Khan, Saleh Ahmed Ortiz, Gabriel Calderon Ibreljic, Ahmed Hwang, Jinwoo Bhuiyan, A.F.M. Anhar Uddin Department of Electrical and Computer Engineering University of Massachusetts Lowell LowellMA01854 United States Lincoln Laboratory Massachusetts Institute of Technology LexingtonMA02421 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

In the rapidly evolving field of quantum computing, niobium nitride (NbN) superconductors have emerged as integral components due to their unique structural properties, including a high superconducting transition temperature, exceptional electrical conductivity, and compatibility with advanced device architectures. This study investigates the impact of high temperature annealing and high dose gamma irradiation on the structural, electrical and superconducting properties of NbN films grown on GaN via reactive DC magnetron sputtering. The as-deposited cubic δ-NbN (111) films exhibited high intensity distinct x-ray diffraction (XRD) peak, a high superconducting transition temperature (Tc) of 12.82 K, and an atomically flat surface. Annealing at 500 °C and 950 °C for varying durations revealed notable structural and surface changes. High resolution scanning transmission electron microscopy (STEM) indicated improved local ordering, while atomic force microscopy (AFM) showed reduced surface roughness after annealing. X-ray photoelectron spectroscopy (XPS) revealed a gradual increase in the Nb/N ratio with higher annealing temperatures and durations. High-resolution XRD and STEM analysis showed lattice constant modifications in δ-NbN films, attributed to residual stress changes following annealing. Additionally, XRD φ-scans revealed sixfold symmetry in NbN films due to rotational domains relative to GaN. While Tc remained stable after annealing at 500 °C, increasing the annealing temperature to 950 °C degraded Tc to ~8 K and reduced the residual resistivity ratio (RRR) from 0.85 in as-deposited films to 0.29 after 30 minutes. The effects of high-dose gamma radiation (5 Mrad (Si)) were also studied, demonstrating minimal changes to crystallinity and superconducting performance, indicating excellent radiation resilience. These findings highlight the potential of NbN superconductors for integration into advanced quantum devices and its suitability for applications in radiatio

关键词： Gallium nitride

Predicting Mechanical Properties of Carbon Nanotube (CNT) Images Using Multi-Layer Synthetic Finite Element Model Simulations

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Predicting Mechanical Properties of Carbon Nanotube (CNT) Im...

IEEE International Conference on Image Processing

作者： Kaveh Safavigerdini Koundinya Nouduri Ramakrishna Surya Andrew Reinhard Zach Quinlan Filiz Bunyak Matthew R. Maschmann Kannappan Palaniappan Department of Electrical Engineering and Computer Science University of Missouri-Columbia Columbia Missouri USA Department of Mechanical & Aerospace Engineering University of Missouri-Columbia Columbia Missouri USA MU Materials Science and Engineering Institute University of Missouri-Columbia Columbia Missouri USA

We present a pipeline for predicting mechanical properties of vertically-oriented carbon nanotube (CNT) forest images using a deep learning model for artificial intelligence (AI)-based materials discovery. Our approach incorporates an innovative data augmentation technique that involves the use of multi-layer synthetic (MLS) or quasi-2.5D images which are generated by blending 2D synthetic images. The MLS images more closely resemble 3D synthetic and real scanning electron microscopy (SEM) images of CNTs but without the computational cost of performing expensive 3D simulations or experiments. Mechanical properties such as stiffness and buckling load for the MLS images are estimated using a physics-based model. The proposed deep learning architecture, CNTNeXt, builds upon our previous CNTNet neural network, using a ResNeXt feature representation followed by random forest regression estimator. Our machine learning approach for predicting CNT physical properties by utilizing a blended set of synthetic images is expected to outperform single synthetic image-based learning when it comes to predicting mechanical properties of real scanning electron microscopy images. This has the potential to accelerate understanding and control of CNT forest self-assembly for diverse applications.

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