The development of energy-efficient and highly sensitive ultraviolet (UV) photodetectors (PDs) is vital for applications in environmental monitoring, biomedical diagnostics, and optical communication. While conventional thin-film devices are limited by low surface area and restricted light absorption, three-dimensional (3D) nanostructures offer a promising alternative by enhancing light-matter interaction and carrier collection. This study introduces a 3D UV photodetector architecture composed of aerosol-printed silver (Ag) mesh combined with seedless hydrothermally grown zinc oxide (ZnO) nanorods (NRs). The aerosol printing process is optimized to form high-aspect-ratio Ag mesh structures on glass substrates, which serve simultaneously as conductive scaffolds and nucleation sites, enabling the direct growth of vertically aligned ZnO NRs. The resulting 3D Ag/ZnO structure forms Schottky junctions that facilitate efficient charge separation and internal gain, thereby enhancing the PDs' performance. Under a low operating bias of 0.1 V and weak UV illumination (1 mu W cm-2), the device exhibits outstanding performance, including a responsivity of 1.2 & times; 103 A W-1, detectivity of 8.52 & times; 1012 Jones, and an external quantum efficiency (EQE) of 4.08 & times; 105%. Additionally, the PDs are tested over a range of temperatures, showing excellent thermal stability. These developments provide a versatile platform to design hierarchical nanoarchitectures for next-generation optoelectronic systems.
This study reports a graphite-core, multiphase gradient C-Si-N composite architecture for Si-containing graphite-based negative electrodes in lithium-ion batteries. The increase in electrode thickness is used as a practical metric of expansion-driven degradation. The composite is prepared by the simultaneous nitridation and carbonization of a graphite core-Si precursor using polyvinylpyrrolidone (PVP) as the N source. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy indicates a quasi-continuous radial trend in the relative N signal toward the outer shell, consistent with preferential N enrichment near the particle exterior. This spatially distributed N arrangement may spatially separate the Si-rich expansion-prone region from the carbon-rich exterior containing nitrides and other N-bearing species, thereby enabling stress partitioning. The shell architecture is designed to disperse expansion-induced stress and stabilize the electrode-electrolyte interface. During electrochemical cycling, the C-Si-N electrode with 10% PVP preserves its core-shell morphology and exhibits the smallest average electrode thickness expansion (similar to 58% after 40 cycles, based on four independent cells). The reduced thickness growth is discussed in relation to a mechanically robust Si-N matrix (Si3N4-like/SiNx-like), potential Li-N interphase species, and N-containing carbon, together with the post-mortem morphology and electrochemical impedance evolution. This study presents reduced swelling as an electrode-level trend versus nominal PVP addition, along with associated nitride-related signatures, thereby highlighting spatially graded stress buffering as an electrode-level design principle.
This study systematically investigates the influence of post-metallization annealing (PMA) ambient on the electrical and interfacial properties of a-IGZO thin-film transistors (TFTs) incorporating BEOL-compatible tungsten (W) contacts. The devices were annealed at 300 degrees C and 350 degrees C using oxygen rapid thermal annealing (O2 RTA) and high-pressure deuterium annealing (HPDA). The HPDA-treated devices exhibited enhanced electrical performance, including reduced subthreshold swing (74 mV dec-1), increased Ion/Ioff ratio, and lowered contact resistance (RCW = 5.74 Omega cm). These improvements are attributed to the passivation of interfacial defects and the formation of W-D bonds, which effectively suppress interfacial oxidation. Furthermore, based on density functional theory (DFT) calculations, it was noted that HPDA promotes W-D bond formation, which can play an important role as an oxygen diffusion barrier. These theoretical results give a physical basis for the dual role of deuterium in defect passivation and suppression of interfacial oxidation at the W electrode, consistent with the HPDA observations of decreased W 4f binding energy and reduced WOx formation.
The fractal market hypothesis highlights multi-scale dynamics in financial time series and provides a theoretical foundation for pattern-based analysis. This study proposes a model-free visual pattern mining framework that transforms high-frequency market data into image representations to support intelligent decision-making. By converting 1-minute KOSPI200 futures data into candlestick chart and Bollinger band images, the method effectively captures structural patterns and volatility dynamics. The framework applies similarity metrics and Intersection over Union (IoU)-based visual comparison to identify historically similar patterns and generate intelligent trading signals without model training or complex parameter tuning. Experimental results demonstrate that combining visual features of candlestick and Bollinger bands achieves a cumulative return of 11.676
