Search Results (299)

Diamond, renowned for its exceptional electrical, physical, and chemical properties, including ultra-wide bandgap, superior hardness, high thermal conductivity, and unparalleled stability, serves as an ideal candidate for next-generation high-power and high-temperature electronic devices. Among diamond-based devices, Schottky barrier diodes (SBDs) have garnered significant attention due to their simple architecture and superior rectifying characteristics. This review systematically summarizes recent advances in diamond SBDs, focusing on both metal–semiconductor (MS) and metal–interlayer–semiconductor (MIS) configurations. For MS structures, we critically analyze the roles of single-layer metals (including noble metals, transition metals, and other metals) and multilayer metals in modulating Schottky barrier height (SBH) and enhancing thermal stability. However, the presence of interface-related issues such as high densities of surface states and Fermi level pinning often leads to poor control of the SBH, limiting device performance and reliability. To address these challenges and achieve high-quality metal/diamond interfaces, researchers have proposed various interface engineering strategies. In particular, the introduction of interfacial layers in MIS structures has emerged as a promising approach. For MIS architectures, functional interlayers—including high-k materials (Al₂O₃, HfO₂, SnO₂) and low-work-function materials (LaB₆, CeB₆)—are evaluated for their efficacy in interface passivation, barrier modulation, and electric field control. Terminal engineering strategies, such as field-plate designs and surface termination treatments, are also highlighted for their role in improving breakdown voltage. Furthermore, we emphasize the limitations in current parameter extraction from current–voltage (I–V) properties and call for a unified new method to accurately determine SBH. This comprehensive analysis provides critical insights into interface engineering strategies and evaluation protocols for high-performance diamond SBDs, paving the way for their reliable deployment in extreme conditions. Full article

Laser ranging technology holds a key position in the military, aerospace, and industrial fields due to its high precision and non-contact measurement characteristics. As a core component, the performance of the photon detector directly determines the ranging accuracy and range. This paper systematically reviews the technological development of photonic detectors for laser ranging, with a focus on analyzing the working principles and performance differences of traditional photodiodes [PN (P-N junction photodiode), PIN (P-intrinsic-N photodiode), and APD (avalanche photodiode)] (such as the high-frequency response characteristics of PIN and the internal gain mechanism of APD), as well as their applications in short- and medium-range scenarios. Additionally, this paper discusses the unique advantages of special structures such as transmitting junction-type and Schottky-type detectors in applications like ultraviolet light detection. This article focuses on photon counting technology, reviewing the technological evolution of photomultiplier tubes (PMTs), single-photon avalanche diodes (SPADs), and superconducting nanowire single-photon detectors (SNSPDs). PMT achieves single-photon detection based on the external photoelectric effect but is limited by volume and anti-interference capability. SPAD achieves sub-decimeter accuracy in 100 km lidars through Geiger mode avalanche doubling, but it faces challenges in dark counting and temperature control. SNSPD, relying on the characteristics of superconducting materials, achieves a detection efficiency of 95% and a dark count rate of less than 1 cps in the 1550 nm band. It has been successfully applied in cutting-edge fields such as 3000 km satellite ranging (with an accuracy of 8 mm) and has broken through the near-infrared bottleneck. This study compares the differences among various detectors in core indicators such as ranging error and spectral response, and looks forward to the future technical paths aimed at improving the resolution of photon numbers and expanding the full-spectrum detection capabilities. It points out that the new generation of detectors represented by SNSPD, through material and process innovations, is promoting laser ranging to leap towards longer distances, higher precision, and wider spectral bands. It has significant application potential in fields such as space debris monitoring. Full article

In this study, a novel silicon carbide (SiC) double-trench MOSFET (DT-MOS) combined Schottky barrier diode (SBD) and MOS-channel diode (MCD) is proposed and investigated using TCAD simulations. The integrated MCD helps inactivate the parasitic body diode when the device is utilized as a freewheeling diode, eliminating bipolar degradation. The adjustment of SBD position provides an alternative path for reverse conduction and mitigates the electric field distribution near the bottom source trench region. As a result of the Schottky contact adjustment, the reverse conduction characteristics are less influenced by the source oxide thickness, and the breakdown voltage (BV) is largely improved from 800 V to 1069 V. The gate-to-drain capacitance is much lower due to the removal of the bottom oxide, bringing an improvement to the turn-on switching rise time from 2.58 ns to 0.68 ns. These optimized performances indicate the proposed structure with both SBD and MCD has advantages in switching and breakdown characteristics. Full article

The advancement of microwave wireless power transfer technology has positioned low-power rectennas as a research hotspot. This paper systematically reviews core technological progress in low-power rectennas, focusing on innovations in rectifier circuit topologies, nonlinear device models, antenna array optimization, and efficiency enhancement strategies. Current technical bottlenecks and future application directions are analyzed, providing theoretical references for space solar power stations, IoTs, and related fields. Full article

This paper focuses on hybrid piezo–electromagnetic generators, which are assembled from a magnetic repulsion pad made of two disk magnets, a sliding cylindrical magnet placed inside a tube, a coil, and an assembly of piezoelectric elements connected with the magnetic pad, as well as an electronic system for rectification and voltage adjustment. Four piezo–electromagnetic generators have been developed. Two linear generators without magnetic cores were tested and optimized for low-frequency (0.2 Hz…5 Hz) and low-amplitude body movements. The other two generators were also designed to handle high-vibration amplitudes, to generate up to 2.2–2.5 W of power. An algorithm for the calculation and modeling of these hybrid generators is presented, as well as simulation models. In addition, an electronic hybrid voltage converter was realized. It was observed that the system harvesting efficiency was increased by adding a large capacitive buffer made of electrolytic capacitors after the Schottky diode rectifiers bridges. This capacitive buffer, together with the electronic pre-regulator, has the role of limiting the voltage to the desired input value and of being the first charging stage. Finally, in the second charging stage, an electronic converter is used to charge the supercapacitors. Full article

This paper presents a rectifying metasurface (RMS) that enables wide-angle, polarization-insensitive wireless energy harvesting in the Wi-Fi frequency range. The RMS consists of a metasurface integrated with rectifying diodes, a low-pass filter (LPF), and a resistive load. In the structural design, the RMS incorporates four Schottky diodes placed on the bottom structure and connected to the top structure through four metallized vias. This configuration facilitates impedance matching between the metasurface and the diodes, omitting the need for conventional rectifier circuits or external matching networks and removing the impact of soldering variations. A 3 × 3 RMS prototype was manufactured and subjected to experimental validation. The measurements confirm that the RMS achieves a peak RF-to-DC conversion efficiency of 68.3% at 5.8 GHz with a 12.5 dBm input power, while maintaining stable performance across a wide range of incident angles and polarization states. Full article

This work employs a deep learning method to develop a high-precision model for predicting the breakdown voltage (V_br) and forward I-V characteristics of silicon carbide Schottky barrier diodes (SiC SBDs). The model significantly reduces the testing costs associated with destructive experiments, such as breakdown voltage testing. Although the model requires a certain amount of time to establish itself, it supports linear variations in related variables once developed. A predicted model for V_br with an accuracy of up to 99% was successfully developed using 600 sets of input data after 200 epochs of training. After training for 1000 epochs, the deep learning-based model could predict not only point values like V_br but also curves, such as forward I-V characteristics, with a mean squared error (MSE) of less than 10⁻³. Our research shows the applicability and high efficiency of introducing deep learning into device characteristic prediction. Full article

Gallium Arsenide (GaAs) Schottky technology stands out for its superior performance in terms of conversion loss for terahertz mixers at room temperatures, which establishes it as a dominant solution in receivers for high-data-rate wireless communications. However, Indium Gallium Arsenide (InGaAs) Schottky mixers offer a notable advantage in terms of reduced power requirements due to their lower barrier height, enabling optical pumping with the incorporation of photodiodes acting as photonic local oscillators (LOs). In this study, we present the first comparative analysis of GaAs and InGaAs diode technologies under both electrical and optical pumping, which are also being compared for the first time, particularly in the context of a wireless communication system, transmitting up to 80 Gbps at 0.3 THz using 16-quadrature amplitude modulation (QAM). The terahertz transmitter and the optical receiver’s LO are based on modified uni-traveling-carrier photodiodes (MUTC-PDs) driven by free-running lasers. The investigation covers a total of two mixers, including narrow-band GaAs and InGaAs. The results reveal that, despite InGaAs mixers exhibiting higher conversion loss, the bit error rate (BER) can be as low as that with GaAs. This is attributed to the purity of optically generated LO signals in the receiver. This work positions InGaAs Schottky technology as a compelling candidate for terahertz reception in the context of optical wireless communication systems. Full article

Radio frequency identification (RFID) technology has gained significant attention in various industry sectors due to its potential for efficient inventory management, asset tracking, and object localization. Different RFID technologies are available; resorting to harmonic signals is currently less used but, recently, has gained interest in research activity. In this study, we present the design, prototype realization, and performance evaluation of a dual-band dual-polarized harmonic tag. The tag incorporates a dual-band matching circuit utilizing a zero-bias Schottky diode HSMS-2850 connected to a perturbed annular ring patch antenna. The antenna, in fact, is able to radiate in cross-polarization at the higher frequency. Through a comprehensive design methodology, including simulation optimization and prototype fabrication, we demonstrate the successful implementation of the tag. Measurements to validate the impedance matching properties, radiation patterns, and backscattering capability of the tag are also shown. Full article

Traditional proportional–integral–derivative (PID) controllers are often utilized in industrial control applications due to their simplicity and ease of implementation. This study presents a novel control strategy that integrates the Groupers and Moray Eels Optimization (GMEO) algorithm with a Dual-Stream Multi-Dependency Graph Neural Network (DMGNN) to optimize PID controller parameters. The approach addresses key challenges such as system nonlinearity, dynamic adaptation to fluctuating conditions, and maintaining robust performance. In the proposed framework, the GMEO technique is employed to optimize the PID gain values, while the DMGNN model forecasts system behavior and enables localized adjustments to the PID parameters based on feedback. This dynamic tuning mechanism enables the controller to adapt effectively to changes in input voltage and load variations, thereby enhancing system accuracy, responsiveness, and overall performance. The proposed strategy is assessed and contrasted with existing strategies on the MATLAB platform. The proposed system achieves a significantly reduced settling time of 100 ms, ensuring rapid response and stability under varying load conditions. Additionally, it minimizes overshoot to 1.5% and reduces the steady-state error to just 0.005 V, demonstrating superior accuracy and efficiency compared to existing methods. These improvements demonstrate the system’s ability to deliver optimal performance while effectively adapting to dynamic environments, showcasing its superiority over existing techniques. Full article

This paper presents a preliminary investigation into the total dose effects and displacement damage effects on β-Ga₂O₃ Schottky barrier diodes (SBDs) induced by X-rays with an average energy of 8–20 keV and 1 MeV reactor neutrons. The electrical performance of the devices before and after irradiation was evaluated through direct current (I-V) and capacitance–voltage (C-V) measurements. The results indicate that under X-ray irradiation, as the irradiation fluence increases, the forward current density, leakage current, and reverse current density of the devices increase, suggesting a progressive degradation of device performance with higher irradiation fluence. In the case of neutron irradiation, the forward current density decreases, while the leakage current and reverse current density increase with rising irradiation fluence. By employing techniques such as low-frequency noise (LFN) and deep-level transient spectroscopy (DLTS), changes in defect concentrations before and after irradiation were analyzed. It was found that the primary causes of device performance degradation are the interface defects induced by X-ray irradiation and the increased bulk defect concentration caused by neutron irradiation. These findings were further validated through two-dimensional numerical simulations using TCAD tools, providing significant theoretical insights and experimental data to enhance reliability and optimize the design of such devices. Full article

In this paper, we investigated the effects of the processing parameters, such as deposition methods, annealing temperature, and metal thickness, on the electrical characteristics of Ti/4H-SiC contacts. A reduction of the Schottky barrier height from 1.19 to 1.00 eV following an increase of the annealing temperature (475–700 °C) was observed for a reference contact with an 80 nm-thick Ti layer. The current transport mechanisms can be described according to the thermionic emission (TE) and thermionic field emission (TFE) models under forward and reverse biases, respectively. The comparison with an e-beam evaporated Ti(80 nm)/4H-SiC contact did not show significant differences for the forward characteristics, while an increase of the leakage current was observed under high reverse voltage (>500 V). Finally, a thickness variation from 10 to 80 nm induced a reduction of the Schottky barrier height, due to the reaction occurring at the interface with a Ti-Al region extended up to the 4H-SiC surface. In addition to a deeper understanding of the Schottky barrier properties, this work is useful for the development of Schottky barrier diodes with tailored characteristics. Full article

In this work, the electrical properties of the Ga₂O₃ Schottky barrier diodes (SBDs) using W/Au as the Schottky metal were investigated. Due to the 450 °C post-anode annealing (PAA), the reduced oxygen vacancy defects on the β-Ga₂O₃ surface resulted in the improvement in the forward characteristics of the W/Au Ga₂O₃ Schottky diode, and the breakdown voltage was significantly enhanced, increasing by 56.25% from 400 V to 625 V after PAA treatment. Additionally, the temperature dependence of barrier heights and ideality factors was analyzed using the thermionic emission (TE) model combined with a Gaussian distribution of barrier heights. Post-annealing reduced the apparent barrier height standard deviation from 112 meV to 92 meV, indicating a decrease in barrier height fluctuations. And the modified Richardson constants calculated for the as-deposited and annealed samples were in close agreement with the theoretical value, demonstrating that the barrier inhomogeneity of the W/Au Ga₂O₃ SBDs can be accurately explained using the TE model with a Gaussian distribution of barrier heights. Full article

Radio-frequency (RF) microwave wireless power transfer (WPT) offers an efficient means of delivering energy to a wide array of devices over long distances. Previous RF WPT systems faced significant challenges, including complex hardware and control systems, software deficiencies, insufficient rectification power, lack of high-performance substrate materials, and electromagnetic radiation hazards. Addressing these issues, this paper proposes the world’s first watt-level RF WPT system capable of intelligent continuous tracking and occlusion judgment. Our 5.8 GHz band RF WPT system integrates several advanced technologies, such as millimeter-precision lidar, the multi-object image recognition algorithm, the accurate 6-bit continuous beamforming algorithm, a compact 16-channel 32 W high-power transmitting system, a pair of ultra-low axial ratio circularly polarized antenna arrays, ultra-low-loss high-strength ceramic substrates, and a 2.4 W high-power Schottky diode array rectifier achieving a rectification efficiency of $66.8\%$. Additionally, we construct a platform to demonstrate the application of the proposed RF WPT system in battery-free vehicles, achieving unprecedented ${360}^{\circ }$ uninterrupted power supply to the battery-free vehicle. In summary, this system represents the most functionally complete RF WPT system to date, serving as a milestone for several critical fields such as smart living, transportation electrification, and battery-less/free societies. Full article

The polyol method under a single pot has successfully produced a coating of CuO, TiO₂, and the combination of CuO/TiO₂ around Ag NWs under sequential addition. The Ag NWs and their coating with a pure metal oxide and a hybrid of metal oxide were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with EDX, X-ray photoelectron spectroscopy (XPS), UV–Visible, photoluminescent (PL) spectroscopy, and cyclic voltammetry (CV). The formation of ultra-thin NWs was also been seen in the presence of the TiO₂ coating. The ultra-thin and co-axial coating of each metal oxide and their hybrid form preserved the SPR of the Ag NWs and demonstrated photon harvesting from the 400–800 nm range. The band gap hybridization was confirmed by CV for the Ag@CuO/TiO₂ design, which made the structure a reliable catalyst. Therefore, the material expresses excellent photocatalytic activities for carcinogenic textile dyes such as turquoise blue (TB), sapphire blue (SB), and methyl orange (MO), with and without the reagent H₂O₂. The hybrid form (i.e., Ag@CuO/TiO₂) exhibited degradation within 6 min in the presence of H₂O₂. Additionally, the material showed antibacterial activities against various bacteria (Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Bacillus pumilus) when assayed using broth media. Therefore, the materials have established degrading and disinfection roles suitable for environmental perspectives. The role of coating with each metal oxide and their hybrid texture further improved the growth of Ag NWs. The preparatory route possibly ensued metal–metal oxide and metal–hybrid metal oxide Schottky junctions, which would expectedly transform it into a diode material for electronic applications. Full article