Negative differential resistance (NDR)-in which current decreases with increasing voltage-represents nonlinear behavior in nanoscale devices, offering unique opportunities to probe carrier dynamics and field-matter interactions beyond conventional monotonic responses. While NDR has become a recurring feature in devices based on emerging materials, its occurrence in standard complementary metal-oxide-semiconductor (CMOS) transistors has been exceedingly rare. Achieving NDR within a CMOS-compatible platform is highly desirable, as it enables compact nonlinear functionalities without the need for multi-device circuits or additional biasing networks. Here we report the first experimental demonstration of two distinct NDR mechanisms in fully depleted silicon-on-insulator (FDSOI) transistors fabricated using an industry-standard CMOS process. At the drain terminal, a previously unreported NDR regime emerges at high drain bias due to hot-carrier injection into the drain-side dielectric, where localized trapping perturbs the electric field and suppresses impact ionization. In the body terminal, by contrast, NDR arises from the interplay of gate-induced drain leakage and lateral-field-enhanced impact ionization, achieving an unprecedented peak-to-valley ratio of 2.37 × 104 at 1.0 V with exceptional stability. Building on these findings, we demonstrate that the steep, low-voltage body-terminal NDR directly enables a reconfigurable frequency doubler within a single transistor. By linking terminal-specific transport dynamics to device-level nonlinear functions, this work establishes both a new physical framework for understanding NDR in silicon transistors and a CMOS-compatible route to compact, energy-efficient nonlinear circuit elements.

The escalating threats posed by global warming are intensifying freshwater and energy scarcity, driving the demand for integrated systems that harvest fog and supply power. However, existing systems are challenged because high-efficiency fog harvesters lack energy supply, whereas droplet-based generators have low water yield. Herein, we present a novel bioinspired integrated system that combines synergistic biomimetic dendritic structured surface with a droplet-based triboelectric nanogenerator for simultaneously harvest water and generate energy. Specifically, the synergistic biomimetic dendritic structured surface combines Laplace force, capillary force, and surface wetting gradient, enabling barrier-free droplet transport and highly efficient fog harvesting. Moreover, the optimized MXene-PDMS with Superhydrophobicity prevents water retention and deposit shielding on the triboelectric layer, enlarging the electrostatic area and enhancing charge output. Remarkably, the optimized SBDSS achieves a 9.7 g·cm−2·h−1 fog harvesting rate, representing 125% and 430% of unprocessed and non-UV-irradiated surfaces, respectively. The integrated D-TENG provides a new approach for efficient harvesting energy from fog droplets in practical environments, with enhanced durability and stability. Intriguingly, the novel bioinspired integrated system supports the growth of barley (Hordeum vulgare), providing freshwater and LED lighting for plant growth. This system offers a viable solution to address water and energy challenges in agricultural systems.

Micro lithium-ion batteries (MLIBs) are promising power devices for miniaturized intelligent terminals, but are limited by low energy density and poor cycling stability. Among potential anodes, cobalt oxide (CoO) offers a high theoretical capacity while suffering from low electrical conductivity and structural degradation. Herein, we propose a synergistic 0D-2D CoO/MXene heterostructure anode with uniformly anchored CoO nanoparticles on Ti3C2 MXene nanosheets, enabling facilitated interfacial charge transfer and high-rate performance for advanced MLIBs. In this architecture, the nanosized CoO particles alleviate pulverization, shorten ion diffusion pathways, and amplify active sites, while the conductive, robust MXene framework facilitates electron conduction, ion transport, and accommodates mechanical strains. The intimate CoO-MXene vdW interface further enables synergistic charge coupling, leading to accelerated interfacial kinetics and enhanced electrochemical stability. The heterostructure is fabricated by a facile solvothermal strategy involving electrostatic adsorption of Co2+, MXene-guided nucleation, and oriented growth, which effectively suppresses CoO aggregation and MXene oxidation. Interfacial characterizations verify noncovalent vdW coupling, confirming intimate atomic contact and excluding covalent bonding features. As a result, the CoO/MXene 0D-2D van der Waals heterostructure achieves an ultrahigh reversible capacity of 1282.3 mAh g−1 after 100 cycles. It also exhibits an outstanding rate capacity of 731.7 mA h g−1 at 0.8 A g−1 for over 300 cycles. Notably, when the current density is returned to 0.1 A g−1 after high-rate cycling, the capacity recovers to 1111.6 mAh g−1, demonstrating remarkable structural integrity and electrochemical reversibility. Furthermore, density functional theory (DFT) calculations analyzed that the MXene-CoO heterostructure enhances conductivity through increased density of states near the Fermi level, optimizes interfacial charge-transfer kinetics to strengthen Li adsorption, and lowers Li⁺ diffusion barriers, collectively contributing to the improved rate performance and cycling stability. This work establishes a novel and controllable strategy for constructing 0D-2D vdW heterostructures and provides mechanistic insights into structure-property relationships, offering a practical pathway toward high-performance anodes for MLIBs applications.

Over the past decade, the reported planar vacuum electron tubes (VETs) have not yet succeeded in resolving the gate leakage issue due to inherent limitations of their working principles, preventing their circuit integration thus far. This paper proposes a cathode modulated vacuum/air channel electron tube (CMVET), which completely solves the long-standing gate leakage problem. Furthermore, the developed CMVET has been integrated into fundamental circuit blocks and successfully applied in common-source amplifiers, differential amplifiers, cascode amplifiers, as well as NOR and NAND gates, thereby demonstrating its functionality and laying a foundation for further research on monolithic electron tube integrated circuits.

This work describes a hybrid micro-electro-mechanical-systems (MEMS) microphone integrating capacitive and piezoelectric transduction mechanisms for signal-to-noise ratio (SNR) improvement. A theoretical system-level model was established to characterize the hybrid device, which was fabricated using a silicon-on-insulator (SOI) wafer-based process. The piezoelectric transduction component employs a Si/SiO2/Au/AlN/Pt material stack, while the capacitive transduction part consists of a variable capacitor formed by a silicon handle layer and a silicon device layer. Experimental results at 1 kHz show that the hybrid MEMS microphone achieves sensitivities of -64.3 dB (re: 1 V/Pa) in piezoelectric mode, -54.9 dB (re: 1 V/Pa) in capacitive mode, and -52.4 dB (re: 1 V/Pa) in hybrid mode, with corresponding SNR values of 65.7 dB, 59.8 dB, and 62.2 dB, respectively. To enhance the overall SNR of the hybrid MEMS microphone, a signal fusion technique is applied to the dual synchronized signals, resulting in an enhanced SNR of 66.7 dB, exhibiting a 14.1 dB improvement compared to the 52.6 dB reported in previous work.

Metasurfaces have emerged as transformative platforms for manipulating light at subwavelength scales, enabling functionalities such as wavefront shaping, polarization control, and holography within ultrathin optical elements. However, the realization of high-efficiency metasurfaces in the visible spectrum remains limited by complex and time-costly nanofabrication processes involving a thick layer of high-index material deposition, hard mask patterning, and plasma-based etching. Here, we present a streamlined, etch-free nanofabrication strategy based on electron-beam resist that directly serves both as the patterning medium and the functional material. The polymeric nanostructures are patterned through a single-step lithography process, eliminating the need for etching or lift-off, which significantly reduces fabrication complexity. To overcome the intrinsic limitations of low-index resist, we introduce an ultrathin (28 nm) atomic layer of TiO2 conformally deposited onto the resist structures. This hybrid architecture leverages the high-index of TiO2 and enables strong light confinement, leading to efficiency exceeding 90% in the visible. We demonstrate high-efficiency geometric-phase holograms and measurements before and after TiO2 coating reveal a fourfold improvement in diffraction efficiency, validating the critical role of the high-index shell. The proposed method can offer a robust route to the prototype-to-production of flat optical components for next-generation display, imaging, and photonic systems.

This study introduces a bio-inspired AlN-piezoelectric MEMS microphone that showcases a cantilever structure offering adjustable performance, fully emulating the dynamics and tunability observed in the basilar membrane of the mammalian cochlea. Through the incorporation of piezoelectric and converse piezoelectric effects alongside dual parametric modulation mechanisms, the device successfully replicates three crucial aspects of cochlear mechanics: i) sensory transduction characteristic of inner hair cell (IHC); ii) local stiffness modulation enabled by outer hair cell (OHC) somatic motility; and iii) energy redistribution in coupled-system recapitulating the energy transfer of cochlear traveling wave dynamics. The device performance was systematically characterized through electrical characterizations, optical analysis, and acoustic measurements. Experimental results demonstrate a baseline sensitivity of -25.38 dB/Pa and signal-to-noise ratios up to 79.28 dB within an operation bandwidth from 1.755 to 2.261 kHz (3 dB cut-on and cut-off bandwidth), while the quality factor (Q) can be tuned to a value ranging from -55.38% to 180.10% of initial values, representing a 124.72% tuning span. In essence, the critical innovations encompass: i) a MEMS microphone that pioneers the first fully mimicking simultaneous sensing/tuning functionality of the mammalian cochlea, through piezoelectric and converse piezoelectric effects; ii) a combination of two novel tuning mechanisms, i.e., AC (through parametric modulation) and mechanical coupling, are applied without the necessity for mechanical structure modification. It can be envisioned that such a technology enables next-generation hearing aids with bio-inspired auditory adaptation, bridging a critical gap in prosthetic sound processing, while also catering to the ever-increasing demands of intelligent acoustic sensors.

In order to solve the shortcomings of wireless passive sensors based on label chips for signal transmission, which cannot withstand high temperatures, and the problem of the short transmission distance of wireless passive sensors without chips, a wireless passive high-temperature frequency-doubling microstrip antenna sensor based on a high-temperature-resistant Schottky diode is proposed. The sensor utilizes the characteristic of the resonant frequency of the microstrip antenna changing with temperature. The high-temperature-resistant platinum sensitive structure integrated on alumina ceramic adapts to temperature measurement in harsh environments such as high temperatures, oxidation, and corrosion. A high-temperature-resistant Schottky diode was designed, and on this basis, a high-temperature-resistant frequency doubling circuit was designed and implemented. Through this circuit, the network analyzer can transmit a fundamental frequency signal and receive a modulated double frequency signal, while limiting ambient noise to the fundamental frequency band, eliminating interference, and significantly improving the signal-to-noise ratio, thereby enabling wireless transmission. In addition, a high-temperature-resistant, miniaturized broadband coplanar waveguide antenna was designed to replace the traditional horn antenna as the interrogation antenna, which realized the wireless transmission of sensor signals. A high-temperature testing system was set up to test the sensor performance in the range of 15–800 °C. The results showed that the maximum transmission distance of the sensor is 20 cm, and the transmission performance is best at 10 cm away from the interrogation antenna. It can accurately characterize the temperature during the heating process, with a sensitivity of up to 181 KHz/°C and a frequency error of no more than 0.2%.

In this study, we present a novel reusable surface acoustic wave (SAW)-based particulate matter (PM) sensor system capable of simultaneously and selectively detecting PM10 and PM2.5. This is the first implementation of an integrated porous microstructure membrane, acting as a mechanical filter for particle separation, combined with an on-board microheater for particle detachment, enabling sensor reusability. The membrane featured holes of approximately 3 µm and 11 µm in diameter, allowing for selective detection of PM2.5 and PM10, respectively. A two-port SAW resonator structure and 128° YX LiNbO₃ substrate was selected for the sensor platform. The microheater was co-fabricated with the SAW sensor to reduce additional processing time and cost. The porous membrane filter was placed over the sensor, covering only the interdigital transducers (IDTs) and reflectors. COMSOL simulations were used to analyze the heater’s thermal performance, particle trajectories, and eventual particle detachment following microheater activation. For experiments, highly sensitive and stable multi-channel interface electronics were developed to monitor real-time frequency shifts. Sensors were tested in a vacuum chamber with manually controlled particle inlet and microheater. Testing was conducted using PM10 and PM2.5 fine dust, and the sensor demonstrated high sensitivity to both PM categories. A detailed calibration study was performed to ensure the system exclusively detects PM10 and PM2.5. After exposing the sensor surface to three different concentrations of PM, the microheater was activated by applying 12 V, allowing the device to reach a maximum temperature of approximately 100 °C. This facilitated the sensor’s recovery to baseline levels under vacuum conditions, making the sensor reusable.

Flexible electronics demand stretchable, high-performance interconnects for wearable and implantable applications. However, conventional methods such as direct-ink writing or doped-activator metallization face challenges including thermal degradation risks from high-temperature sintering, complex multi-step chemical procedures with toxic precursors. Here, we introduce an updated laser-induced selective metallization (LISM) for fabricating stretchable copper electrodes directly on a commercial polysiloxane rubber. This approach employs a spray-coated copper carbonate hydroxide activator, followed by near-infrared laser activating. Laser irradiation leads to the reduction of copper ions, along with the formation of amorphous carbon domains and micro-nanoscale surface structures. Electroless copper plating (ECP) and electroplating (EP) are subsequently performed to form continuous, low-resistivity serpentine traces. Comprehensive characterization verifies the successful reduction of copper and the robust integration of the electrode into the substrate. Mechanical testing shows that the structure maintains its electrical performance under repeated cyclic deformation. Functional demonstrations including electrocardiogram (ECG) patch, LED arrays, and wireless antennas showcase practical applicability of the proposed approach. Additionally, LISM operates at ambient temperature without toxic precursors and it minimizes chemical consumption and provides exceptional durability. This method advances next-generation electronics requiring both mechanical flexibility and electrical reliability.