Tyndall National Institute - Journal Articles
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Item Ultrafast dynamics of hot carriers: Theoretical approaches based on real-time propagation of carrier distributions(American Institute of Physics, 2025-02-14) Sjakste, Jelena; Sen, Raja; Vast, Nathalie; Saint-Martin, Jerome; Ghanem, Mohammad; Dollfus, Philippe; Murphy-Armando, Felipe; Kanasaki, Junichi; Japan Society for the Promotion of Science; Science Foundation Ireland; Agence Nationale de la RechercheIn recent years, computational approaches which couple density functional theory (DFT)-based description of the electron–phonon and phonon–phonon scattering rates with the Boltzmann transport equation have been shown to obtain the electron and thermal transport characteristics of many 3D and 2D semiconductors in excellent agreement with experimental measurements. At the same time, progress in the DFT-based description of the electron–phonon scattering has also allowed to describe the non-equilibrium relaxation dynamics of hot or photo-excited electrons in several materials, in very good agreement with time-resolved spectroscopy experiments. In the latter case, as the time-resolved spectroscopy techniques provide the possibility to monitor transient material characteristics evolving on the femtosecond and attosecond time scales, the time evolution of photo-excited, nonthermal carrier distributions has to be described. Similarly, reliable theoretical approaches are needed to describe the transient transport properties of devices involving high energy carriers. In this review, we aim to discuss recent progress in coupling the ab initio description of materials, especially that of the electron–phonon scattering, with the time-dependent approaches describing the time evolution of the out-of-equilibrium carrier distributions, in the context of time-resolved spectroscopy experiments as well as in the context of transport simulations. We point out the computational limitations common to all numerical approaches, which describe time propagation of strongly out-of-equilibrium carrier distributions in 3D materials, and discuss the methods used to overcome them.Item Thermal and electrical study of glass interposers in co-packaged electronic-photonic systems(IEEE, 2025-01-23) Gupta, Parnika; Mallik, Arun Kumar; Krohnert, Kevin; Latkowski, Sylwester; Okonkwo, Chigo; Alomari, Saif; Kumar, Das Soumitra; Gradkowski, Kamil; Morrissey, Padraic E.; O’Brien, Peter; Horizon 2020This paper investigates the use of glass interposers as a scalable and cost-effective solution for co-packaged electronic-photonic systems, with a focus on optimizing thermal management and electrical transmission. The thermal management study is carried out through design, assembly and characterization of a thermal test vehicle. The thermal test vehicle is used to study the heat dissipation in glass interposers by varying the Through Glass Via (TGV) pitch (100 μm to 400 μm). The outcomes indicate a maximum surface temperature rise of 2.9 °C, which is also confirmed by finite element method simulations. Moreover, the simulations also suggest that changes in TGV pitch below 100 μm do not significantly impact the temperature variation. The electrical transmission through the glass interposer package is investigated using three different design scenarios (Transmission Lines on Glass, Glass Interposer and Electrical Test Vehicle). The RF performance of each design is studied up to 40 GHz to analyze the losses incurred by different components in the package. In conclusion, this work presents an optimized electrical design for the test vehicle. By employing strategically designed geometries for TGVs, microvias, and ball grid array (BGA) pads, we achieved a significant reduction in insertion loss of approximately 11 dB at 40 GHz. This design approach can be compatible with 2.5D and 3D integration schemes, enabling high-density and high-performance electronic-photonic packages.Item Improving dynamic endurance time predictions for shoulder fatigue: A comparative evaluation(Elsevier Ltd., 2025-02-24) O'Sullivan, Patricia; Menolotto, Matteo; O'Flynn, Brendan; Komaris, Dimitrios-Sokratis; Research Ireland; European Regional Development FundWork-related musculoskeletal disorders (WMSDs) are commonplace in industry and a host of qualitative and quantitative approaches have been used to assuage the problem, including wearable sensors and biomechanical endurance models, both of which were used in the present study. Six endurance models (consumed endurance, new improved consumed endurance and the exponential and power Frey Law and Avin general and shoulder models) with four alternative maximum torque (Torquemax) quantification methods, including a novel approach to generate Torquemax, were compared. The proposed approach to quantify Torquemax, in combination with the new improved consumed endurance model produced the lowest root mean square errors (RMSE), and indicated improved performance compared to the literature. The mean RMSE was reduced from 41.08s to 19.11s for all subjects, from 26.13s to 12.16s for males, and 51.28s to 24.45s for females using the proposed method. R2 for 25% and 45% standardised intensity dynamic tasks were .459 and .314 respectively, P < .01. This research provided an optimised and individualised endurance prediction approach for loaded dynamic movements which can be applied to industry tasks and may lead to reduced upper-limb strains, and potentially WMSDs.Item Di-tert-butyl disulfide as a replacement for hydrogen sulfide in the atomic layer deposition of two-dimensional molybdenum disulfide(American Chemical Society, 2025-02-11) Campbell, Ian E.; Gupta, Aashi; Metaxa, Pavlina; Arifutzzaman, A.; Ma, Tao; Arellano, Paula; Duffy, Ray; Bol, Ageeth A.; Science Foundation Ireland; Nederlandse Organisatie voor Wetenschappelijk Onderzoek; Horizon 2020Atomic layer deposition (ALD), with its precise process control and conformality, has recently gained interest for synthesizing transition metal sulfides like MoS2, which have varied applications in low-dimensional electronics and electrocatalysts. Hydrogen sulfide (H2S) has been used in many sulfide ALD processes; however, H2S is a toxic gas that requires expensive containment and abatement measures for shipping, installation, and storage. Herein, we report a PEALD process capable of synthesizing MoS2 without H2S. This process utilizes a Mo precursor commonly used in ALD, hydrogen plasma, and di-tert-butyl disulfide (TBDS), which is a liquid that is significantly less hazardous and expensive than H2S. It was found that the TBDS-based PEALD process results in layered, stoichiometric MoS2 with limited contamination. The TBDS-based PEALD process was also analyzed via mass spectrometry to determine the mechanistic roles of each reactant. Apparently, H2 plasma removes ligands from the chemisorbed Mo precursor, which allows TBDS to sulfurize the top layer, producing H2S and isobutene as byproducts. MoS2 films deposited via the TBDS-based process possessed fewer yet taller out-of-plane growths and similar crystal grain diameter (∼10 nm) and electrical resistivity (13.6–15.5 Ω·cm for 3 nm thick films) compared to films made with H2S. Thus, the TBDS-based process is a suitable and safer alternative to the H2S-based process for large-area synthesis of layered MoS2.Item Perspectives on decarbonisation of existing buildings in Europe(Elsevier Ltd., 2025-01-28) Gillett, W. B.; Kalogirou, S. A.; Morthorst, P. E.; Norton, Brian; Ornetzeder, M.Decarbonisation of existing buildings is necessary to meet European Union commitments to achieve net zero GHG emissions by 2050. There is no single decarbonisation solution because European buildings are diverse, have different uses and are in different climatic regions. This paper discusses choosing the depth of building renovation, selecting sustainable technologies to cost-effectively decarbonise buildings, and the potential benefits for occupants' health and comfort, energy security and increased building value. The potential for re-using and recycling building materials and components is highlighted, together with the need to reduce embodied as well as operating emissions when renovating buildings. Key actors needed to decarbonise Europe’s existing buildings include policy makers, investors, banks, financing institutions, the construction industry and the research community. In 2021, the European Academies' Science Advisory Council (EASAC) published a report on decarbonising buildings and this paper aims to bring the findings to the scientific community. Since the EASAC report was published, more research has been published on decarbonising buildings through renovation, and a revised Energy Performance of Buildings Directive has been adopted (in 2024). This paper recognises these recent developments and offers a broad science-based perspective on the potential benefits and challenges of decarbonising existing buildings in Europe.