arXiv subjects

Mohamed Awadein

Publications and source records attributed to Mohamed Awadein.

4 recordsLinked to original sources

arXiv2026

Parallel Spatial Photonic Programming of Optoelectronic IGZO RRAM with a compact $\mu$LED Array

Optoelectronic resistive random-access memory elements (ORRAM) are critical emerging devices that leverage photonic technologies to bring the advantages of optical programming to traditionally electronic memristive platforms for neuromorphic computing and artificial intelligence. In this work, a free-space optic micro-LED ($\mu$LED) array is combined with a 2-terminal oxide semiconductor ORRAM (based on IGZO\textsubscript{Rich}/IGZO active layers), to realise parallel spatial programming of form-free memristive arrays. We report the optical and electrical programming of resistive states with potentiation/depression analysis of various stimuli parameters (pulse frequency, pulse width, pulse amplitude). Further, we demonstrate the simultaneous photonic-electronic programming of the ORRAM with optical SET (blue 450\,nm) and electrical RESET functionality. Persistent photocurrent is also observed and exploited as a pathway to fading memory or synaptic plasticity for temporal bit encoding. Finally, parallel optical $\mu$LED to ORRAM channels are demonstrated to achieve the simultaneous photonic programming of multiple devices and the writing of spatial patterns across a chip of memristive IGZO devices. This work highlights the light-enabled scalability of the optoelectronic platform and the feasibility of ORRAM to interface with spatially-multiplexed optical sources to bring neuromorphic technologies directly into applications that process and sense in the optical domain.

physics.optics↗

arXiv2025

Multibit Ferroelectric Memcapacitor for Non-volatile Analogue Memory and Reconfigurable Filtering

Tuneable capacitors are vital for adaptive and reconfigurable electronics, yet existing approaches require continuous bias or mechanical actuation. Here we demonstrate a voltage-programmable ferroelectric memcapacitor based on HfZrO that achieves more than eight stable, reprogrammable capacitance states (3-bit encoding) within a non-volatile window of 24~pF. The device switches at low voltages (3~V), with each state exhibiting long retention (10^5~s) and high endurance (10^6 cycles), ensuring reliable multi-level operation. At the nanoscale, multistate charge retention was directly visualised using atomic force microscopy, confirming the robustness of individual states beyond macroscopic measurements. As a proof of concept, the capacitor was integrated into a high-pass filter, where the programmed capacitive states shift the cutoff frequency over 5~kHz, establishing circuit-level viability. This work demonstrates the feasibility of CMOS-compatible, non-volatile, analogue memory based on ferroelectric HfZrO, paving the way for adaptive RF filters, reconfigurable analogue front-ends, and neuromorphic electronics.

cond-mat.mtrl-sci↗

arXiv2024

Microwaves reveal the nanoscale ion intercalation and edge activity of 2D catalyst

The accelerated demand for electrochemical energy storage urges the need for new, sustainable, stable and lightweight materials able to store high energy densities rapidly and efficiently. Development of these functional materials requires specialized techniques that can provide a close insight into the electrochemical properties at the nanoscale. For this reason, we have introduced the electrochemical scanning microwave microscopy (EC-SMM) enabling local measurement of electrochemical properties with nanometer spatial resolution and sensitivity down to atto-Ampere electrochemical currents. The exceptional power of EC-SMM operated at radio frequency is exemplified here by the successful detection of the electrochemical activity and dynamics of molecularly thin NiCo(OH)2 flakes with a spatial resolution of 16 +/- 1 nm, uncovering the location of the active sites and providing atomistic details on the catalytic process that controls the electrocatalytic performance. Our results pinpoint the factors required to tune the thermodynamics of ion intercalation and to optimize the surface adsorption.

physics.chem-ph↗

arXiv2021

High-sensitivity electrochemical dual-QCM for reliable three-electrode measurements

Electrochemical quartz crystal microbalance (EC-QCM) is a versatile gravimetric technique that allows for parallel characterization of mass deposition and electrochemical properties. Despite its broad applicability, simultaneous characterization of two electrodes remains challenging due to practical difficulties posed by the dampening from fixture parasitics and the dissipative medium. In this study, we present a dual electrochemical QCM (dual EC-QCM) that is employed in a three-electrode configuration to enable consequent monitoring of mass deposition and viscous loading on two crystals, the working electrode (WE) and the counter electrode (CE). A novel cor-rection approach along with a three standard complex impedance calibration is employed to overcome the effect of dampening while keeping high spectral sensitivity. Separation of viscous loading and rigid mass deposition is achieved by robust characterization of the complex impedance at the resonance frequency. Validation of the presented system is done by cyclic voltammetry characterization of Ag underpotential deposition on gold. The results indicate mass deposition of 412.2 ng for the WE and 345.6 ng for the CE, reflecting a difference of the initially present Ag adhered to the surface. We also performed higher harmonic measurements that further corroborate the sensitivity and reproducibility of the dual EC-QCM. The demonstrated approach is especially intriguing for electrochemical energy storage applications where mass detection with multiple electrodes is desired.

physics.chem-ph↗