ACS Applied Electronic Materials最新文献

This work demonstrates a reactive ion etching (RIE)-assisted interface engineering approach to overcome efficiency limitations in GaN-based micro-LEDs. By progressively thinning the n-GaN layer from its initial 6 μm thickness to 200 nm, we achieve substantial improvements in device performance. The optimal configuration with 389 nm n-GaN thickness delivers a peak luminance of 43,807 cd/m² at 12 V bias─representing a 12-fold enhancement compared to untreated devices. Combined optical simulation and electrical characterization confirm that this specific thickness provides the best compromise between the optical extraction efficiency and electrical characteristics. This study validates interface engineering through controlled thinning as an effective strategy for developing high-brightness micro-LEDs suitable for augmented and virtual reality displays.

Recent advancements in energy-harvesting technologies have led to the development of systems that efficiently convert mechanical energy into electrical power, offering sustainable solutions for a wide range of applications. In particular, piezoelectric materials are paving the way for high-performance, flexible devices capable of energy conversion, storage, and sensing, addressing the growing demand for self-powered and eco-friendly systems. In this study, we present a simple approach to stabilize α-FAPbI₃ by incorporating it into a PVDF matrix, resulting in a stable composite film. Optimized FPC 3 composite containing 300 μL of α-FAPbI₃/g in PVDF achieved high electroactive-phase formation (∼96%). A comparative study demonstrated that the black phase (α-FAPbI₃) outperformed the yellow phase (δ-FAPbI₃) due to superior interfacial interactions. The optimized device, FPNG 3, generated a peak-to-peak output voltage of ∼148.4 V and a maximum power density of ∼81.72 μW/cm². Additionally, the device exhibited high pressure sensitivity (∼1.036 kPa/V at 10-Hz frequency and a moderate pressure range) with the ability to sense various biomechanical movements. The light-assisted nanogenerator device displayed output variations under no light, white light, and UV light exposure, making it suitable for photoassisted energy harvesting. A ∼63.5% increase in output voltage was observed from the photoassisted energy-harvesting device under white light. Overall, this research highlights the multifunctionality of the FAPbI₃–PVDF composite in energy conversion, storage, and sensing, along with an effective method for stabilizing the metastable, photoactive α-FAPbI₃. Additionally, a machine learning framework utilizing LSTM networks was employed for real-time gesture recognition and classification of the energy-harvesting behavior of the FPNG device. This approach enables real-time performance optimization, enhancing applications in sign language recognition, human–computer interaction, and sensor systems.

Magneto-dielectric composites have potential applications in efficient microwave absorption (MA) in the 2–8 GHz band. However, their development for lower-frequency applications is hindered by the complex structure–property relationship, making precise regulation of magneto-dielectric properties quite challenging. In this work, we develop high-performance microwave absorbers via rational heterointerface engineering. Guided by electromagnetic theory, we construct a functional composite material with multiple heterointerfaces and magnetic phases by introducing magnetic elements and a self-templated etching process. This tailored architecture significantly enhances the magneto-dielectric properties, leading to exceptional MA performance in the low- and midfrequency bands. The optimized FeNi/FeCo@C composites with a thickness of 2.88 mm exhibit a minimum reflection loss (RL_min) of −52.6 dB at 8.04 GHz, demonstrating strong attenuation. Furthermore, with a thickness of 4.48 mm, it achieves an RL_min of −58.9 dB at 4.68 GHz and an effective absorption bandwidth of 1.4 GHz. This work provides a feasible pathway for designing advanced MA materials for low- and medium-frequency applications through heterointerface engineering.

Flexible photodetectors are increasingly important for emerging wearable and portable electronic systems, where mechanical adaptability and low-weight substrates are essential. Motivated by this need, the present work explores a paper-based AgI/Fe-doped PbS heterostructure photodetector fabricated using a simple successive ionic layer adsorption and reaction (SILAR) technique, demonstrating broadband UV–Vis–NIR sensitivity, reliable photoswitching behavior, and strong mechanical stability under repeated bending. This work presents a distinct AgI/Fe-doped PbS heterostructure photodetector fabricated on a cellulose paper substrate through a simple and inexpensive SILAR technique. XRD results confirm a higher crystalline nature and the coexistence of AgI and Fe-doped PbS phases, while SEM studies reveal a distinctly nanostructured surface morphology. Energy dispersive spectrometry (EDS) is performed to confirm the elemental quantification, especially to obtain the doping profile. UV–Vis absorption studies display wide spectral coverage, with bandgap values of 2.8 eV for AgI and 1.26 eV for Fe-doped PbS, ensuring strong photodetection capability across multiple wavelength regions. The detector exhibits rapid switching characteristics, with response/recovery times of 1.60 s/3.12 s (for UV), 2.98 s/2.13 s (for visible), and 1.37 s/1.64 s (for NIR), which are notably higher than those of other flexible photodetectors. It further achieves improved detectivity values of 13.20 × 10⁸ Jones (for UV-395 nm), 55.87 × 10⁸ Jones (for visible-550 nm), and 18.70 × 10⁸ Jones (for NIR-780 nm), along with stable responsivities of 0.15 mA/W (for UV), 0.66 mA/W (for visible), and 0.21 mA/W (for NIR). The incorporation of AgI and Fe-doped PbS improves charge separation and carrier transport, enabling effective broadband UV–Vis–NIR sensing. In comparison to previous studies, this device provides an uncommon blend of room-temperature fabrication, high flexibility, and detailed multiwavelength performance analysis, establishing it as a practical and sustainable photodetector platform. Moreover, the device maintains a stable performance after 1200 mechanical bending cycles, highlighting its robustness for flexible and wearable electronics. With its broadband response, fast photoswitching, and structural durability, the AgI/Fe-doped PbS heterojunction photodetector presents strong potential for diverse optoelectronic applications.

The escalating generation of electronic waste underscores the critical need for sustainable alternatives to conventional electronic technologies. Printed electronics emerge as a promising approach to address this issue by incorporating sustainable materials, implementing energy-efficient fabrication methods compatible with large-area manufacturing, and integrating end-of-life (EoL) strategies to minimize the environmental impact associated with waste management. In this work, we demonstrate fully printed Schottky diodes on kraft paper substrates fabricated using zinc (Zn) as a sustainable ohmic contact, zinc oxide (ZnO) nanoparticles as the semiconductor layer, and carbon nanotubes (CNTs) as the Schottky contact. The devices were manufactured using large area deposition processes at low-temperature and with vacuum-free printing techniques. The Cheung, Norde, and Mikhelashvili methods enabled the estimation of an effective Schottky barrier height of 0.75 ± 0.04 eV, a series resistance of 2.2 ± 1.5 kΩ, and a high ideality factor of 8.0 ± 1.4, which was corrected to 5.1 when it was voltage independent. These analyses also revealed the presence of trap states and the onset of a space-charge-limited current (SCLC) regime, with these electrical properties interpreted being considered and correlated with the morphological and structural characterizations. The diode exhibited a rectification ratio of (1.6 ± 1.2) × 10³ and, in a proof-of-concept demonstration, successfully performed half-wave rectification, underscoring its potential for low-power and low-frequency sustainable electronic circuits on paper. Finally, life cycle assessments (LCA) showed the adopted manufacturing approaches and materials provide a lower impact route for fabricating sustainable diodes.

Carbon nanotubes (CNTs), owing to their high aspect ratio and excellent electrical conductivity, are promising candidates for field electron emission (FE) applications. Fabricating them into free-standing carbon nanotube films, also known as buckypapers, can significantly enhance emission current and operational stability. However, conventional fabrication methods such as vacuum filtration suffer from limitations including nonuniform deposition, prolonged processing time, and residual impurities, which restrict their large-scale application in FE devices. In this work, we propose an efficient electrophoretic deposition (EPD) approach to fabricate uniform, mechanically robust, and thickness-tunable (3–50 μm) single-walled carbon nanotube (SWCNT) buckypapers and systematically evaluate their field emission characteristics. The EPD-derived films exhibit smooth and dense morphology, reduced impurity and defect content, and excellent mechanical strength. The 3 μm-thick free-standing film achieves an ultralow turn-on field of 0.81 V/μm and delivers a remarkably high current density of 18.4 A/cm² at 1.52 V/μm. Annealing at 450 °C further enhances FE performance, yielding a maximum current density of 122.8 A/cm². The EPD-fabricated SWCNT buckypapers exhibit exceptional performance, high processing efficiency, and remarkable structural stability, highlighting their significant potential for flexible vacuum microelectronic applications.

The continuous increase in global energy consumption is primarily driven by the rapid expansion of urban areas and acccelerated industrialization. This has led to a need for the integration of renewable energy systems, aimed at enhancing sustainability, alongside the demand for more efficient technologies for energy harvesting and storage. In this context, supercapacitors and batteries have gained vital importance, as they can store and swiftly release energy with high efficiency to meet the needs of electric mobility, renewable energy integration, and advanced electronic devices. A continuous increase in energy demand highlights the need for the sustainability of the materials used in their construction, but currently, these devices are mainly prepared from nonrenewable or toxic materials. In this direction, the search for green alternatives using natural and abundant materials, such as carbon-based nanofibers, has gained prominence. Carbon-based nanofibers present remarkable electrical and mechanical properties, combined with high surface area and porosity. Moreover, their carbonaceous nature facilitates integration into circular economy frameworks. Techniques such as electrospinning and solution blow spinning (SBS) are effective for producing carbon fibers at both micro- and nanoscale, making them well-suited for energy storage applications. Accordingly, this review explores recent developments in carbon nanofibers derived from renewable sources and evaluates their potential performance as advanced materials for energy storage applications, particularly supercapacitors and batteries.

The development of high-performance gas sensors for real-time detection of triethylamine (TEA) remains challenging due to sensitivity limitations and interference from coexisting gases. To address these challenges, a ZnIn₂S₄/TiO₂ heterostructure was fabricated in this work via a facile hydrothermal strategy to harness the synergistic n-n heterojunction effects. Structural characterizations via SEM, TEM, and XPS verified that TiO₂ nanoparticles are uniformly dispersed on the surface of ZnIn₂S₄ microflowers, forming a well-defined hierarchical heterostructure with intimate interfacial contact─features that lay a fundamental structural basis for efficient charge transfer and abundant active sites, thereby contributing to the enhanced gas-sensing performance. The sensing tests revealed the optimized sensor (ZnIn₂S₄/TiO₂-20) to exhibit outstanding performances at 150 °C, with a response toward 50 ppm TEA reaching 120.2, coupled with rapid response/recovery times of 11 s/12 s, a detection limit of 1 ppm. Notably, the sensor exhibits no significant performance degradation even after 45 cycles of repeatability tests and a 90-day durability test. The mechanistic studies revealed the heterojunction to promote carrier transport and surface adsorption, while TiO₂-induced oxygen vacancies enhance the reactive site densities. To mitigate false alarms in complex environments, a KNN+PCA machine learning model was integrated to achieve 100% binary classification accuracy for TEA/non-TEA gases. Overall, the combination of ZnIn₂S₄/TiO₂ heterostructures with machine learning has potential for reliable TEA monitoring in industrial real complex environments.

Neuromorphic computing circuits can be realized by using memristors based on low-dimensional materials enabling enhanced metal diffusion for resistive switching. Here, we investigate memristive properties of vertically aligned MoS₂ (VA-MoS₂) films with three different metal electrodes: Ag, Cu, and Au. Despite having the same active material, all three metals show distinct switching behavior, which is crucial for neuromorphic computing applications: Ag enables volatile switching, Cu demonstrates stable nonvolatile switching with retention over 2500 s, and Au shows no memristive response. Cu devices show abrupt resistance changes and a significant increase of copper content upon biasing, indicative of stable nonvolatile switching based on filament formation and rupture. About 85% of Ag and Cu devices exhibit reliable memristor behavior. Our findings provide valuable insights into the memristive switching mechanism in VA-MoS₂ and present a promising avenue for facile fabrication of neuromorphic circuits by employing a set of different metals on a single active material.

Subsurface defects’ visualizations in chips become increasingly important as their feature sizes approach the subnanometer regime. In this study, a high-resolution contact resonance scanning thermal expansion microscopy (CR-STEM) was set up and employed to visualize the embedded defects inside the chips. Two types of defects with spot and line-like microstructures were clearly imaged by CR-STEM. The defect imaging contrast mechanism is attributed to different Joule thermal expansions of the buried structures due to their thermal resistance differences. Furthermore, the frequency-dependent behavior of defect imaging reveals depth-related profiles of subsurface defects. Local thermal stress fields are found to play an important role in the microstructural stability and reliability of the chip. These findings offer insights into the relationship between localized embedded structures and failure mechanisms in semiconductor devices.