Anodic HfO memristors grown in phosphate, borate, or citrate electrolytes and formed on sputtered Hf with Pt top electrodes are characterized at fundamental and device levels. The incorporation of electrolyte species deep into anodic memristors concomitant with HfO crystalline structure conservation is demonstrated by elemental analysis and atomic scale imaging. Upon electroforming, retention and endurance tests are performed on memristors. The use of borate results in the weakest memristive performance while the citrate demonstrates clear superior memristive properties with multilevel switching capabilities and high read/write cycling in the range of 10. Low temperature heating applied to memristors shows a direct influence on their behavior mainly due to surface release of water. Citrate-based memristors show remarkable properties independent on device operation temperatures up to 100 °C. The switching dynamic of anodic HfO memristors is discussed by analyzing high resolution transmission electron microscope images. Full and partial conductive filaments are visualized, and apart from their modeling, a concurrency of filaments is additionally observed. This is responsible for the multilevel switching mechanism in HfO and is related to device failure mechanisms.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8001223 | PMC |
http://dx.doi.org/10.3390/nano11030666 | DOI Listing |
Adv Sci (Weinh)
January 2025
Department of Materials Science and Metallurgy, University of Cambridge, CB3 0FS, Cambridge, UK.
The discovery of ferroelectric phases in HfO-based films has reignited interest in ferroelectrics and their application in resistive switching (RS) devices. This study investigates the pivotal role of electrodes in facilitating the Schottky-to-Ohmic transition (SOT) observed in devices consisting of ultrathin epitaxial ferroelectric HfYO (YHO) films deposited on LaSrMnO-buffered Nb-doped SrTiO (NbSTO|LSMO) with Ti|Au top electrodes. These findings indicate combined filamentary RS and ferroelectric switching occurs in devices with designed electrodes, having an ON/OFF ratio of over 100 during about 10 cycles.
View Article and Find Full Text PDFJ Neurosci Methods
December 2024
Ecole Nationale de l'Aviation Civile, (ENAC), Toulouse 31300, France. Electronic address:
Background: Fast-ripples (FR) are short (∼10 ms) high-frequency oscillations (HFO) between 200 and 600 Hz that are helpful in epilepsy to identify the epileptogenic zone. Our aim is to propose a new method to detect FR that had to be efficient for intracerebral EEG (iEEG) recorded from both usual clinical macro-contacts (millimeter scale) and microwires (micrometer scale).
New Method: Step 1 of the detection method is based on a convolutional neural network (CNN) trained using a large database of > 11,000 FR recorded from the iEEG of 38 patients with epilepsy from both macro-contacts and microwires.
Epilepsia
December 2024
Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
Objective: This study was undertaken to anatomically categorize insulo-opercular focal cortical dysplasia (FCD) lesions according to their location and extent, and to summarize corresponding stereoelectroencephalographic (SEEG) patterns to guide preoperative evaluation and surgical planning.
Methods: Patients who underwent epilepsy surgery for insulo-opercular FCD between 2015 and 2022 were enrolled. FCD lesions were categorized into insular, peri-insular, opercular, and complex types based on their location and extent, as ascertained from electroclinical and neuroimaging data.
ACS Appl Mater Interfaces
December 2024
State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology and Guangdong Province Key Laboratory of Display Material, Sun Yat-sen University, Guangzhou 510275, China.
Integrating high-quality dielectrics with two-dimensional (2D) transition metal chalcogenides (TMDCs) is crucial for high-performance electronics. However, the lack of dangling bonds on 2D material surfaces complicates direct dielectric deposition. We propose using atomic layer deposition (ALD) to integrate ultrathin high-κ dielectric directly on 1T'-MoTe surfaces, facilitating the creation of high-performance back-gated field-effect transistors (FETs).
View Article and Find Full Text PDFMaterials (Basel)
November 2024
NANOTECH Centre, Ural Federal University, Mira Str., 19, 620002 Ekaterinburg, Russia.
Nanotubular hafnia arrays hold significant promise for advanced opto- and nanoelectronic applications. However, the known studies concern mostly the luminescent properties of doped HfO-based nanostructures, while the optical properties of nominally pure hafnia with optically active centers of intrinsic origin are far from being sufficiently investigated. In this work, for the first time we have conducted research on the wide-range temperature effects in the photoluminescence processes of anion-defective hafnia nanotubes with an amorphous and monoclinic structure, synthesized by the electrochemical oxidation method.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!