Search Results (392)

Electrothermal actuators, with their simple structure, small size, strong anti-interference ability, and easy integration, have emerged as a promising solution for micro-drive technology. However, deploying them in extreme environments, such as the fuze systems—which demand exceptional reliability under high mechanical overloads. In this study, a device based on multi-electrothermal co-actuation is designed for the fuze system of loitering munition. The overall structure and work principle of the multi-electrothermal co-actuation device is discussed. Considering application environments, the effect factors of V-beam numbers, air gap, type of contact surface, external load force, periodic voltage and gas damping on the output performance of the multi-electrothermal co-actuation device are systematically addressed via simulation and experimental method. Furthermore, the high overload resistance performance of the co-actuation device applied in loitering munition is studied. The results show that the proposed multi-electrothermal co-actuation device could operate stably under a high overload (12,000 g/73.79 μs) environment, fully meeting the demanding requirements of fuze system for loitering munition. In addition, this study identifies laser processing-induced thermal gradients and mechanical stresses as critical fabrication challenges. This study provides significant insights into the design and optimization of multi-electrothermal actuation systems for next-generation fuze applications, establishing a valuable framework for future development in this field. Full article

This study aims to enhance optoelectronic properties of all-inorganic perovskite photodetectors (PDs) by incorporating a bilayer electron transport layer (ETL). The bilayer ETL composed of SnO₂ and ZnO effectively optimizes energy level alignment at the interface, facilitating efficient electron extraction from the CsPbI₂Br perovskite layer while suppressing shunt pathways. Additionally, it enhances interfacial properties by mitigating defects and minimizing dark current leakage, thereby improving overall device performance. As a result, the bilayer ETL-based PDs exhibit broadband photoresponsivity in 300 to 700 nm with a responsivity of 0.45 A W⁻¹ and a specific detectivity of 9 × 10¹³ Jones, outperforming the single-ETL devices. Additionally, they demonstrate stable cyclic photoresponsivity with fast response times (14 μs for turn-on and 32 μs for turn-off). The bilayer ETL also improves long-term reliability and thermal stability, highlighting its potential for high performance, reliability, and practical applications of all-inorganic perovskite PDs. Full article

We present a compact and cost-effective real-time PCR system designed for point-of-care testing (POCT), utilizing a PCB-based disposable chip and an open-platform CMOS camera. The system integrates precise thermal cycling with software-synchronized fluorescence detection and provides real-time analysis through a dedicated user interface. To minimize cost and complexity, a polycarbonate reaction chamber was integrated with a PCB-based heater and thermistor. A slanted LED illumination setup and an open-platform USB camera were employed for fluorescence imaging. Signal alignment was enhanced using device-specific region-of-interest (ROI) tracking based on copper pad corner detection. Thermal cycling performance achieved a heating rate of 8.0 °C/s and a cooling rate of −9.3 °C/s, with steady-state accuracy within ±0.1 °C. Fluorescence images exhibited high dynamic range without saturation, and the 3σ-based ROI correction method improved signal reliability. System performance was validated using Chlamydia trachomatis DNA standard (10³ copies), yielding consistent amplification curves with a Ct standard deviation below 0.3 cycles. These results demonstrate that the proposed system enables rapid, accurate, and reproducible nucleic acid detection, making it a strong candidate for field-deployable molecular diagnostics. Full article

Aligned carbon nanotubes (A-CNTs) are emerging as one of the most promising materials for next-generation nanoelectronics. However, achieving reliable ohmic contacts between A-CNTs and metals remains a critical challenge. In this study, we employ rapid thermal annealing (RTA) to facilitate the formation of transition metal carbides at the metal–CNT interface, significantly reducing contact resistance and enhancing stability. Using the transmission line method (TLM), we demonstrate that RTA reduces the contact resistance at the Ti/A-CNT interface from 112.26 k$\mathrm{\Omega }·\mathrm{\mu }$m to 1.57 k$\mathrm{\Omega }·\mathrm{\mu }$m and at the Ni/A-CNT interface from 81.72 k$\mathrm{\Omega }·\mathrm{\mu }$m to 1.17 k$\mathrm{\Omega }·\mathrm{\mu }$m, representing a reduction of over an order of magnitude. Moreover, the Schottky barrier heights (SBHs) for both the Ti/A-CNT and Ni/A-CNT interfaces decreases by approximately 50% after annealing. A comparative analysis with Pd/A-CNT contacts shows that Ti and Ni contacts exhibit superior reliability under harsh conditions. This work provides a viable solution for improving the electrical performance and reliability of CNT-based devices, offering a pathway toward the development of future CMOS technologies. Full article

As data centers expand, immersion cooling systems are gaining attention for thermal management of memory devices. To enable widespread adoption, it is essential to evaluate the impact of coolants on the reliability of memory packages. In this study, high-voltage direct current (DC) stress tests were conducted on commercial dynamic random access memory (DRAM) packages in both single-phase coolant and air environments to analyze heat generation and electrical characteristics. A DC voltage ranging from 2.5 to 3.1 V, which is higher than the regular operating voltage of 1.2 V, was applied. Temperature changes were measured using an infrared camera in the air, and a contact-based thermometer in the coolant. The leakage current was also evaluated through I-V curve analysis. Heat generation and changes in leakage currents were not significant in either environment until the applied voltage stress exceeded approximately twice the standard voltage (2.5–2.8 V). However, the package’s degradation accelerated when the applied voltages exceeded 3.0 V, demonstrating a nonlinear increase in temperature and leakage current. Full article

Stable and efficient inorganic lead-free double perovskites are crucial for high-reliability optoelectronic devices. However, dual-doped perovskite phosphors often suffer from poor color stability due to differences in thermal activation energies and electron–phonon interactions between the doped ions. To address this, single-doped Sb³⁺-incorporated Rb₂HfCl₆ perovskite crystals were synthesized via a co-precipitation method. Under UV excitation, Rb₂HfCl₆:Sb exhibits broad dual emission bands, attributed to singlet and triplet self-trapped exciton radiative transitions induced by Jahn–Teller distortion in [SbCl₆]³⁻ octahedra. This dual emission endows the material with high sensitivity to excitation wavelengths, enabling tunable luminescence from cyan to orange-red across 400–800 nm. Utilizing this dual emission, a white LED was fabricated, showcasing a high color rendering index and excellent long-term stability. Remarkably, the material exhibits breakthrough thermal stability, maintaining more than 90% of its emission intensity at 100 °C, while also exhibiting remarkable resistance to humidity and oxygen exposure. Compared to co-doped phosphors, Rb₂HfCl₆:Sb offers advantages such as environmental friendliness, simple fabrication, and stable performance, making it an ideal candidate for WLEDs. This study demonstrates notable progress in developing thermally stable and reliable optoelectronic devices. Full article

One of the common reliability tests performed on power modules for automotive applications is passive thermal cycling, which is conventionally representative of the highly demanding thermomechanical loads typical of steady-state operating conditions. The mechanical response of the electronics devices subjected to such testing procedures, in terms of stress-strain response and of damage, is usually predicted by finite elements analyses where the remarkable nonlinearities intrinsic in the phenomena need to be properly addressed. This work regards the FEM modeling of the thermomechanical behavior of a power electronics package subjected to thermal cycles, focusing on the critical importance of modeling the complete elastoplastic behavior of materials, in contrast to the conventional elastic approach. By incorporating the full elastoplastic properties, the study aims to accurately evaluate the actual irreversible deformations and resulting stresses that develop within the package subjected to a representative passive thermal cycle and to compare the outcomes to those from purely elastic simulations. Additionally, damage models are compared for predicting the local detachment of the encapsulating resin from other layers. The predictions of the cohesive zone model (CZM) applied to a conventional interface layer are compared to those of a modified Tresca (MT) stress-dependent damage model applied to the resin bulk material. In addition, the estimate of linear-nonlinear evolutions of plastic strain and of damage at increasing numbers of cycles is investigated in the attempt to identify procedures for guessing the long-term mechanical response from short-term simulations. Full article

High-temperature-resistant epoxy composites play a crucial role in enhancing the operational reliability and service life of devices such as DC bushings, which is of great significance for the long-term stable operation of ultra-high voltage and flexible power transmission and distribution systems. In this study, the epoxy composite was prepared, and long-term thermal aging tests were conducted at 250 °C and 270 °C. The changes in physical properties, electrical characteristics, and bending strength of epoxy composite were systematically investigated, and the thermal aging mechanism of these materials was elucidated. The experimental results revealed that with the progression of thermal aging, the epoxy composites exhibited volume shrinkage due to the breaking of chemical bonds. After 10 thermal aging cycles at 270 °C, the mass loss rate of the epoxy composite reached 20.52%. At 250 °C, the breakdown strength decreased by 9.9% compared to the unaged state. After aging at 250 °C and 270 °C, the volume resistivity decreased by a maximum of 53.75% and 76.94%, respectively, while the dielectric constant decreased by a maximum of 50.34% and 41.94%, respectively. After 10 aging cycles at 250 °C and 270 °C, the bending strength of the cured epoxy composite decreased by 39.79% and 53.91%, respectively. These findings provide valuable insights into the thermal aging characteristics of epoxy composites used in DC bushings and other electrical devices, offering a scientific basis for material selection and reliability assessment in high-voltage insulation applications. Full article

This study presents a full-system simulation methodology for MEMS, addressing the critical need for reliable performance prediction in microsystem design. While existing digital tools have been widely adopted in related fields, current approaches often remain fragmented and focused on specific aspects of device behavior. In contrast, our proposed framework conducts comprehensive device physics-level analysis by integrating mechanical, thermal and electrical modeling with process simulation. The methodology features a streamlined workflow that enables direct implementation of simulation results into fabrication processes. We model a MEMS gyroscope as an example to verify our simulation approach. Multiphysics coupling is considered to capture real-world device behavior, followed by quantitative assessment of manufacturing variations through virtual prototyping and experimental validation demonstrating the method’s accuracy and practicality. The proposed approach not only improves design efficiency but also provides a robust framework for MEMS gyroscope development. With its ability to predict device performance, this methodology is expected to become an essential tool in microsensor research and development. Full article

This study examined the dependability of Transient Voltage Suppression (TVS) diodes under direct current (DC) switching surge stress from several manufacturers with identical electrical requirements. To prevent thermal damage, we applied a standard 3 ms DC switching surge and increased the surge voltage in increments of 0.1 V with intervals between surges. The breakdown voltage (V_BR) was measured after each DC switching surge to verify functionality. To find the maximum surge current and power level that each device could withstand before failing to clamp surge voltage at a defined V_BR level, three separate manufacturers’ TVS diode (V_BR = 6.8 V) samples were examined. There were significant variations in the computed maximum average surge current and power level between manufacturers’ samples determined by statistical analysis. Prior to failure, the average surge power was 202 W, 321 W, and 357 W, while the maximum average surge current was 29.0 A, 46.9 A, and 51.8 A, respectively. Computed 95% confidence interval ranges between manufacturers of TVS diodes revealed significant population reliability differences under DC switching surge stress. Therefore, an efficient TVS diode reliability metric for DC switching surge stress is the maximum average surge current and power immediately before device failure. Full article

With the transformation of the world’s energy structure and the promotion of clean energy, nuclear power has come to the fore as an efficient and environmentally friendly form of energy. As critical components in the operation of nuclear power plants (NPPs), suction and transportation devices for thermal traps—designed to prevent and control floating bodies—are directly linked to the safety of power generation, the stability of operations, and the reliability of the power grid in NPPs. Technical research and advancements in these devices play a crucial role in enhancing their effectiveness. In view of the intrusion and blockage of floating bodies in the sewage network pocket of the water intake with the cold-source system for coastal NPPs, the key technologies to prevent and control floating bodies that may impair cooling resources in NPPs’ thermal traps is discussed. This paper introduces the safety risks and social impacts associated with water intake, highlights the importance of the water-intake system, and discusses the interception and transportation mechanisms in NPPs. The progress of explosive floating bodies’ interception, cleaning, suction, transportation, and intelligent monitoring technology is introduced through the technical progress in the types of floating bodies, as well as cutting, crushing, suction, and transportation devices. The technical progress of efficient treatment is realized, which provides reference for the research and practice of the key technologies for suction and transportation devices to prevent and control floating bodies’ suction and transportation devices in NPPs’ thermal traps. Full article

As semiconductor packaging technologies face limitations, through-silicon via (TSV) technology has emerged as a key solution to extending Moore’s law by achieving high-density, high-performance microelectronics. TSV technology enables enhanced wiring density, signal speed, and power efficiency, and offers significant advantages over traditional wire-bonding techniques. However, achieving fine-pitch and high-density interconnects remains a challenge. Solder flip-chip microbumps have demonstrated their potential to improve interconnect reliability and performance. However, the environmental impact of lead-based solders necessitates a shift to lead-free alternatives. This review highlights the transition from Sn-Pb solders to lead-free options, such as Sn-Ag, Sn-Cu, Sn-Ag-Cu, Sn-Zn, and Bi- or In-based alloys, driven by regulatory and environmental considerations. Although lead-free solders address environmental concerns, their higher melting points pose challenges such as thermal stress and chip warping, which affect device reliability. To overcome these challenges, the development of low-melting-point solder alloys has gained momentum. This study examines advancements in low-temperature solder technologies and evaluates their potential for enhancing device reliability by mitigating thermal stress and ensuring long-term stability. Full article

The emergence of GaN-based micro-LEDs has revolutionized display technologies due to their superior brightness, energy efficiency, and thermal stability compared to traditional counterparts. However, the development of red-emitting micro-LEDs on silicon substrates (GaN-on-Si) faces significant challenges, among them including hydrogen-induced deactivation of p-GaN caused by hydrogen species generated from SiH₄ decomposition during SiO₂ passivation layer growth, which degrades device performance. This study systematically investigates the use of high-density metal-oxide dielectric passivation layers deposited by atomic layer deposition (ALD), specifically Al₂O₃ and HfO₂, to mitigate these effects and enhance device reliability. The passivation layers effectively suppress hydrogen diffusion and preserve p-GaN activation, ensuring improved ohmic contact formation and reduced forward voltage, which is measured by the probe station. The properties of the epitaxial layer and the cross-section morphology of the dielectric layer were characterized by photoluminescence (PL) and scanning electron microscopy (SEM), respectively. Experimental results reveal that Al₂O₃ exhibits superior thermal stability and lower current leakage under high-temperature annealing, while HfO₂ achieves higher light-output power (LOP) and efficiency under increased current densities. Electroluminescence (EL) measurements confirm that the passivation strategy maintains the intrinsic optical properties of the epitaxial wafer with minimal impact on Wp and FWHM across varying process conditions. The findings demonstrate the efficacy of metal-oxide dielectric passivation in addressing critical challenges in InGaN red micro-LED on silicon substrate fabrication, contributing to accelerating scalable and efficient next-generation display technologies. Full article

Radiofrequency fields in the 1–28 GHz range are ubiquitous in the modern world, giving rise to numerous studies of potential health risks such as cancer, neurological conditions, reproductive risks and electromagnetic hypersensitivity. However, results are inconsistent due to a lack of precision in exposure conditions and vastly differing experimental models, whereas measured RF effects are often indirect and occur over many hours or even days. Here, we present a simplified RF exposure protocol providing a single 1.8 GHz carrier frequency to human HEK293 cell monolayer cultures. A custom-built exposure box and antenna maintained in a fully shielded anechoic chamber emits discrete RF signals which can be precisely characterized and modelled. The chosen amplitudes are non-thermal and fall within the range of modern telecommunication devices. A critical feature of the protocol is that cell cultures are exposed to only a single, short (15 min) RF exposure period, followed by detection of immediate, rapid changes in gene expression. In this way, we show that modulation of genes implicated in oxidative stress and ROS signaling is among the earliest cellular responses to RF exposure. Moreover, these genes respond in complex ways to varying RF signal amplitudes consistent with a hormetic, receptor-driven biological mechanism. We conclude that induction of mild cellular stress and reactive oxygen species (ROS) is a primary response of human cells to RF signals, and that these responses occur at RF signal amplitudes within the range of normal telecommunications devices. We suggest that this method may help provide a guideline for greater reliability and reproducibility of research results between labs, and thereby help resolve existing controversy on underlying mechanisms and outcomes of RF exposure in the general population. Full article

Herein, we present a novel method for junction temperature monitoring of GaN HEMT devices to achieve real-time temperature perception at different locations on the device surface. Through sputtering patterned Ti/Pt thermistor strips on the surface of a GaN HEMT device to construct an on-chip array junction temperature monitoring unit, the thermal distribution of the device during operation is fully reflected. The developed temperature monitoring unit exhibited a desirable temperature coefficient of resistance of 0.183%/°C in the range of 25 °C to 205 °C. Comparison with the thermal imager shows that the integrated temperature monitoring unit can accurately reflect the real-time temperature with a monitoring accuracy of more than 95%, which helps to improve the long-term reliability of GaN power devices under actual application conditions of high frequency and high power density. Full article