Journal: Applied Physics Reviews

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Publisher

American Institute of Physics

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ISSN

1931-9401

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2015 - 201922020 - 20256
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Publications1 - 8 of 8
  • Metal oxide semiconductor thin-film transistors for flexible electronics
    Item type: Journal Article
    Petti, Luisa; Münzenrieder, Niko; Vogt, Christian; et al. (2016)
    Applied Physics Reviews
  • Localized charge carriers in graphene nanodevices
    Item type: Journal Article
    Bischoff, Dominik; Varlet, Anastasia; Simonet, Pauline; et al. (2015)
    Applied Physics Reviews
  • Large interfacial Dzyaloshinskii–Moriya interaction of epitaxial perovskite La0.7Sr0.3MnO3 films
    Item type: Journal Article
    Yang, Liu; Zhang, Xiaotong; Wang, Hanchen; et al. (2025)
    Applied Physics Reviews
    The Dzyaloshinskii–Moriya interaction (DMI) is pivotal in stabilizing topological spin textures, a critical aspect of the rapidly advancing field of oxide-based spintronics. While skyrmions and the topological Hall effect have been widely studied in oxide films, experimental verification of interfacial DMI and its underlying mechanisms in oxide interfaces has remained largely unexplored. In this study, we report a significantly large interfacial DMI in La0.7Sr0.3MnO3 (LSMO) films grown on NdGaO3 substrates, with a DMI coefficient of 1.96 pJ/m—one to two orders of magnitude higher than previously observed in oxide systems. Our experiments, coupled with first-principles calculations, reveal that enhanced spin–orbit coupling at the LSMO/NdGaO3 interface, driven by a synergy between the 6s electrons of Nd and the 4f electrons, is the key to this large DMI. This breakthrough opens new avenues for controlling chiral spintronics in oxide-based materials, laying the groundwork for next-generation spintronic and magnonic devices.
  • Hot-carrier optoelectronic devices based on semiconductor nanowires
    Item type: Review Article
    Fast, Jonatan; Aeberhard, Urs; Bremner, Stephen P.; et al. (2021)
    Applied Physics Reviews
    In optoelectronic devices such as solar cells and photodetectors, a portion of electron-hole pairs is generated as so-called hot carriers with an excess kinetic energy that is typically lost as heat. The long-standing aim to harvest this excess energy to enhance device performance has proven to be very challenging, largely due to the extremely short-lived nature of hot carriers. Efforts thus focus on increasing the hot carrier relaxation time and on tailoring heterostructures that allow for hot-carrier extraction on short time and length scales. Recently, semiconductor nanowires have emerged as a promising system to achieve these aims, because they offer unique opportunities for heterostructure engineering as well as for potentially modified phononic properties that can lead to increased relaxation times. In this review we assess the current state of theory and experiments relating to hot-carrier dynamics in nanowires, with a focus on hot-carrier photovoltaics. To provide a foundation, we begin with a brief overview of the fundamental processes involved in hot-carrier relaxation and how these can be tailored and characterized in nanowires. We then analyze the advantages offered by nanowires as a system for hot-carrier devices and review the status of proof-of-principle experiments related to hot-carrier photovoltaics. To help interpret existing experiments on photocurrent extraction in nanowires we provide modeling based on non-equilibrium Green's functions. Finally, we identify open research questions that need to be answered in order to fully evaluate the potential nanowires offer toward achieving more efficient, hot-carrier based, optoelectronic devices.
  • Electrolyte-gated carbon nanotube field-effect transistor-based biosensors: Principles and applications
    Item type: Review Article
    Shkodra, Bajramshahe; Petrelli, Mattia; Angeli, Martina Aurora Costa; et al. (2021)
    Applied Physics Reviews
    Nowadays, there is a high demand for sensitive and selective real-time analytical methods suitable for a wide range of applications, from personalized telemedicine, drug discovery, food safety, and quality control, to defense, security, as well as environmental monitoring. Biosensors are analytical devices able to detect bio-chemical analytes (e.g., neurotransmitters, cancer biomarkers, bio-molecules, and ions), through the combination of a bio-recognition element and a bio-transduction device. The use of customized bio-recognition elements such as enzymes, antibodies, aptamers, and ion-selective membranes facilitates achieving high selectivity. Among the different bio-transduction devices currently available, electrolyte-gated field-effect transistors, in which the dielectric is represented by an ionic liquid buffer solution containing the targeted analyte, are gaining increasing attention. Indeed, these bio-transduction devices are characterized by superior electronic properties and intrinsic signal amplification that allow the detection of a wide range of bio-molecules with high sensitivity (down to pM concentration). A promising semiconducting material for bio-transduction devices is represented by carbon nanotubes, due to their unique electrical properties, nanosize, bio-compatibility, and their simple low-cost processability. This work provides a comprehensive and critical review of electrolyte-gated carbon nanotube field-effect transistor-based biosensors. First, an introduction to these bio-sensing devices is given. Next, the device configurations and operating principles are presented, and the most used materials and processes are reviewed with a particular focus on carbon nanotubes as the active material. Subsequently, different functionalization strategies reported in the literature, based on enzymes, antibodies, aptamers, and ion-selective membranes, are analyzed critically. Finally, present issues and challenges faced in the area are investigated, the conclusions are drawn, and a perspective outlook over the field of bio-sensing technologies, in general, is provided.
  • Time-resolved x-ray imaging of nanoscale spin-wave dynamics at multi-GHz frequencies using low-alpha synchrotron operation
    Item type: Journal Article
    Mayr, Sina; Förster, Johannes; Finizio, Simone; et al. (2024)
    Applied Physics Reviews
    Time-resolved x-ray microscopy is used in a low-alpha synchrotron operation mode to image spin dynamics at an unprecedented combination of temporal and spatial resolution. Thereby, nanoscale spin waves with wavelengths down to 70 nm and frequencies up to 30 GHz are directly observed in ferromagnetic thin film microelements with spin vortex ground states. In an antiparallel ferromagnetic bilayer system, we detect the propagation of both optic and acoustic modes, the latter exhibiting even a strong non-reciprocity. In single-layer systems, quasi-uniform spin waves are observed together with modes of higher order (up to the 4th order), bearing precessional nodes over the thickness of the film. Furthermore, the effects of magnetic material properties, film thickness, and magnetic fields on the spin-wave spectrum are determined experimentally. Our experimental results are consistent with numerical calculations from a micromagnetic theory even on these so-far unexplored time- and length scales.
  • Beyond the chloride threshold concept for predicting corrosion of steel in concrete
    Item type: Review Article
    Angst, Ueli; Isgor, O. Burkan; Hansson, Carolyn M.; et al. (2022)
    Applied Physics Reviews
    All existing models to forecast the corrosion performance of reinforced concrete structures exposed to chloride environments are based on one common theoretical concept, namely, a chloride threshold, as a sharply defined trigger for corrosion, followed by a period of active corrosion. We critically review the resulting treatment of corrosion initiation and propagation as two distinct, successive stages. We conclude that this concept presents a major barrier for developing reliable corrosion forecast models, and that a new approach is needed. In reality, steel corrosion in concrete is a continuous process, that is, rarely separable into uncoupled, sequential phases. We propose that the focus be placed on the quantification of the time- and space-variant corrosion rate from the moment steel is placed in concrete until it reaches the end of the service life. To achieve this, a multi-scale and multi-disciplinary approach is required to combine the scientific and practical contributions from materials science, corrosion science, cement/concrete research, and structural engineering.
  • Unraveling the shell growth pathways of Pd-Pt core-shell nanocubes at atomic level by in situ liquid cell electron microscopy
    Item type: Journal Article
    Dachraoui, Walid; Bodnarchuk, Maryna I.; Vogel, Alexander; et al. (2021)
    Applied Physics Reviews
    Understanding the formation of core-shell nanomaterials is decisive for controlling their growth, structure, and morphology, which is particularly important in catalysis. As a promising material for photo catalysis application, Pd-Pt core-shell nanoparticles (NPs) have been in the spotlight for many years owing to their catalytic performance typically superior to that of pure Pt nanoparticles. The generation of ultra-thin Pt skins of only a few atomic layers on Pd nanoparticles has turned out to be extremely difficult because Pt tends to form islands during deposition instead of a continuous shell. Therefore, understanding the atomic mechanisms of shell formation is critical for atomic-scale design and control of the platinum shell. Here, by using in situ graphene-based liquid cell scanning transmission electron microscopy (STEM), the growth mechanisms of the Pt shell on Pd nanocubes (NCs) are studied in aqueous solution at the atomic level. Pd-Pt core-shell NPs are formed via two distinct mechanisms: (i) at low concentration of Pt atoms, an ultra-thin skin of only a few atomic layers is formed via atom-by-atom deposition and (ii) at higher concentration of Pt atoms, inhomogeneous islands and thick shells are formed via attachment of Pt clusters. Our study provides a route to control core-shell growth and helps us to understand the exact atomic mechanisms of Pt shell growth on Pd seeds.
Publications1 - 8 of 8