Hydrogen incorporation in silicon oxynitride (SiON) dielectric films plays a dual role by passivating electrically active defects while simultaneously acting as a potential source of charge trapping, depending on the chemical-bonding configuration. In this study, plasma-enhanced atomic layer-deposited (PEALD) SiON thin films were fabricated using diisopropylaminosilane and a mixed N2/O2 plasma, and the hydrogen-bonding states were systematically engineered by controlling the N2:O2 plasma flow ratio. Increasing the N2:O2 ratio progressively transformed the SiON network from oxide-rich to nitrogen-rich, resulting in an increased dielectric constant from 4.95 to 6.67 while decreasing the induced trap density from 6.15 × 1011 to 1.84 × 1011 cm–2. An optimized N2:O2 ratio of 250:1 yielded the lowest capacitance–voltage hysteresis (0.10 V), whereas the N2-only plasma process caused a substantial increase in hysteresis (1.85 V) despite its highest hydrogen concentration. Time-of-flight secondary ion mass spectrometry analyses revealed that hydrogen incorporation shifted from O–H-dominated to Si–H/N–H-dominated bonding environments as the nitrogen content increased. Density functional theory calculations further demonstrated that Si–H and Si–N bonds have lower bond dissociation energies than O–H and Si–O bonds, thereby explaining the instability of oxygen-deficient SiNx-like networks under electrical stress. These results demonstrate that the charge-trapping behavior of PEALD SiON films is governed not by the total hydrogen concentration but by the hydrogen-bonding configuration and the structural stability of the Si–O–N network, thereby providing an effective strategy for defect passivation and suppressed charge trapping in dielectric films for advanced semiconductor devices.
Abstract To address the trade-off between high sensitivity and wide linear detection range, as well as the fabrication complexity and mechanical instability of traditional microstructure engineering in flexible capacitive pressure sensors, this work constructs a flexible, low-cost, and high-performance capacitive pressure sensor enabled by double-sided microstructured electrodes combined with a single soft dielectric layer derived from a nitrile protective glove. The results show that the proposed flexible capacitive pressure sensor has a wide pressure detection range of 0.1–180 kPa with sensitivities of 0.95 kPa–1 (0–30 kPa) and 0.13 kPa–1 (30–180 kPa). In addition, it exhibits a low detection limit of approximately 2.5 Pa, negligible drift after 5000 loading–unloading cycles at 10 kPa, and good batch consistency. The pressure sensing mechanism is elucidated based on the changes in microstructure morphology and finite element analysis results. The proposed flexible capacitive pressure sensor is finally demonstrated for various applications such as step counting, Morse code generation, wrist pulse, and respiratory pattern discrimination. This work provides a simple and low-cost approach for fabricating high-performance flexible capacitive pressure sensors.
Abstract Flexible dual-mode sensors that provide synchronized optical and electrical outputs offer a promising platform for self-powered sensing and human–machine interaction. Here, we developed a composite of polydimethylsiloxane (PDMS), copper-doped zinc sulfide (ZnS:Cu), lead zirconate titanate (PZT), and sodium dodecyl sulfate (SDS) that integrates mechanoluminescent feedback and triboelectric signal generation within a flexible active layer. SDS modification promoted a more uniform dispersion of PZT particles in the PDMS matrix, contributing to improved electrical output relative to the corresponding unmodified-PZT composites. Among the tested formulations, the PZSP-3 device achieved a maximum open-circuit voltage of 90.9 V and a transferred charge of 38.0 nC at a 4 mm contact–separation distance. During a 3000 s test at 5 Hz, the current increased initially and showed no sustained decrease under the specified conditions. In a separate single-electrode configuration, handwritten trajectories produced visible mechanoluminescent feedback together with distinguishable pattern-dependent electrical signals. The capacitor tests showed energy storage on the microjoule scale. These results demonstrate an interfacial-engineering strategy for combining mechanical flexibility, enhanced triboelectric performance, and intuitive optical–electrical visualization, and suggest potential for self-powered human–machine interfaces under the tested conditions.
Abstract Ag/Gd2O3/Si metal-oxide-semiconductor (MOS) capacitors incorporating RF-magnetron-sputtered Gd2O3 dielectric layers were fabricated to investigate the influence of dielectric thickness on their structural, optical, interfacial, and electrical properties. Films deposited for 2 and 4 h produced Gd2O3 layers of 16.57 and 33.46 nm, respectively. Increasing deposition time promoted partial structural ordering and increased surface roughness, while the optical bandgap decreased slightly from 5.1 to 5.0 eV. The thicker film’s greater roughness correlated with a higher interface-state density (∼1.02 × 1011 eV–1 cm–2) compared with the thinner film (9.07 × 1010 eV–1 cm–2). Frequency-dependent C–V and G–V measurements revealed clear deep-depletion, depletion, and accumulation regions for both devices; oxide thickness strongly influenced accumulation capacitance, series resistance, and interface behavior. Clockwise C–V hysteresis in both capacitors indicates electron trapping in the Gd2O3 layer. As the sweep voltage increased from ±1 to ±5 V, the memory window widened from 0.66 to 3.05 V for the thinner film and from 1.62 to 3.51 V for the thicker film. The thicker dielectric also had better charge retention, with an extrapolated charge loss of only 3.92% compared to 6.06% for the thinner film. These findings show that tuning Gd2O3 thickness via deposition time is an effective way to optimize interface properties and improve the memory performance of high-k MOS capacitors for future nonvolatile memory applications.
Abstract Electrochemical water electrolysis for hydrogen production offers a feasible way for renewable energy development but still faces significant challenges. Developing high-performance catalysts with high activity, low cost, long-term stability, corrosion resistance, and antisediment aggregation is crucial for the practical application of water electrolysis, particularly seawater electrolysis. For this purpose, we designed a Ni(Fe)P/Ni(Fe)OOH/MXene composite electrocatalyst on an iron foam substrate, which uses a multi-interface structure, Fe self-doping, and incomplete phosphating to jointly adjust the electronic structure and optimize H* absorption. Importantly, the incorporation of MXene significantly enhances electrical conductivity, increases the exposure sites, and facilitates gas release, thereby boosting the hydrogen evolution reaction (HER) performance. Meanwhile, the self-doping of the substrate and vertically staggered nanosheet morphology induced by MXene are utilized to enhance the bonding between the catalyst and substrate, as well as the antisediment aggregation performance, thereby achieving long-term stable operation in an alkaline seawater environment. Consequently, the catalyst demonstrates outstanding HER behavior, achieving 100 mA cm–2 at 140 mV in freshwater and 165 mV in seawater, while maintaining stability for 45 h. Moreover, Ni(Fe)P/Ni(Fe)OOH/MXene was assembled with Fe-Ni(OH)2 into a dual-electrode electrolysis cell, achieving 10 mA cm–2 at only 1.49 V in freshwater, and 1.56 V in natural seawater. This work may open up a prospect for freshwater electrolysis of high efficiency HER catalyst.
