Single-layer Cu and Ag films, as well as bilayer Cu/Ag films, each with a thickness of 6 nm, were deposited on glass substrates by high-vacuum thermal evaporation. Metal nanoparticles were fabricated through laser-induced dewetting using a 1064 nm laser operated at various power levels. The effects of laser power and Ag content on the size of the synthesized nanoparticles and the localized surface plasmon resonance (LSPR) behavior of the films were systematically investigated. The LSPR peak wavelength showed a blue shift with increasing Ag content and laser power, enabling a tunable range from 659 to 406 nm. Overall, the results demonstrate that the LSPR peak position can be effectively tuned by adjusting the laser power and material composition of the nanoparticles. This approach shows strong potential for tailoring the optical properties of thin films for advanced photonic and plasmonic applications.

Centrifugation is conventionally regarded as a mere purification step in nanoparticle synthesis. Here, we challenge this view by demonstrating that centrifugation can be strategically employed as an active trigger to drive a predictable morphological transformation in gold nanoparticles (AuNPs). This study reveals a novel mechanism where repeated centrifugation systematically strips the cetyltrimethylammonium bromide (CTAB) stabilizer from the AuNP surface, inducing a controlled sphere-to-rod reshaping. We meticulously tracked this process: a dramatic drop in zeta potential from a stable + 46 mV to a highly unstable + 13 mV confirmed the loss of colloidal stability, while UV-vis spectroscopy captured the cycle-dependent emergence of a distinct longitudinal surface plasmon resonance (SPR) peak at 720 nm-a classic signature of nanorod formation. Direct transmission electron microscopy (TEM) imaging provided unequivocal visual evidence of the evolution from uniform spherical particles to well-defined nanorods. Moreover, this centrifugation-regulated reshaping provides an orthogonal, physically-driven approach to tuning anisotropy, which complements established chemical, optical, and electrochemical synthesis routes in applications ranging from surface-enhanced Raman spectroscopy to photothermal therapy. Our findings not only offer a deeper understanding of the interplay between mechanical forces and surface chemistry in nanoparticle systems but also open a new avenue for the rational design of anisotropic nanostructures, which serve as versatile platforms for biosensing. After appropriate surface functionalization to ensure biocompatibility, they also hold great promise for targeted therapies.

A thermal evaporation system was used to deposit Ag thin films on glass substrates. The films were dewetted using both a regular laser irradiation approach and a hybrid dewetting process that involved laser irradiation followed by Ag thermal deposition. The study would evaluate and compare the optical characteristics and efficiency in melamine detection within these dewetted films. In the traditional dewetting process, as the laser power increased from 15 to 25 W, the nanoparticles (NPs) size decreased from 162 to 125 nm. Furthermore, an evident optical absorption peak range of 540-600 nm was also observed. Through the hybrid dewetting process, a mixture of small NPs (20 nm) and larger NPs (142-167 nm) were formed. It resulted in two distinct Surface Plasmon Resonance (SPR) peaks at 460 nm and 660 nm, respectively. Notably, a strong Raman peak at 701 cm(-1) emerged when a melamine aqueous solution was placed on the hybrid dewetted surface. Comparing the two methods, the hybrid dewetted sample exhibited enhanced fingerprint peak intensity and a higher analytical enhancement factor (AEF). When operating at laser power of 25 W and a scanning speed of 100 mm/s, the maximum AEF value reached 1.9 x 10(5). The limit of detection for melamine solution in the hybrid dewetted sample was established at 10(-7) M. Hence, the hybrid dewetting process is a potential method to produce the mixed-sized nanoparticles for diverse applications.

Hydrogen is a promising source of clean energy. However, the tanks used to store hydrogen fuel are prone to hydrogen embrittlement and are thus at risk of stress cracking and catastrophic failure. Accordingly, this study deposited single-layer and double-layer Zr, Al, SiO2, Al2O3, Al@Al2O3, and Al@SiO2 films on 316L stainless steel substrates and examined their feasibility as protective coatings by measuring their anti-corrosion properties and hydrogen permeation currents. The results showed that the single-layer Al2O3 film had a higher corrosion resistance than the single-layer SiO2 film and bare 316L substrate. Among all the coatings, the Al@Al2O3 doublelayer coating exhibited the highest protection efficiency of 95 %. Moreover, it showed the lowest hydrogen penetration current density (1.08 x 10-3 A/cm2), the longest hydrogen embrittlement time (16000 s), and the lowest hydrogen content (0.008 mol/cm3). In other words, the Al@Al2O3 double-layer coating combined superior corrosion resistance with excellent hydrogen permeation suppression. Consequently, it is a promising material for enhancing the safety and longevity of hydrogen storage tanks in practical applications.

With an aging population, the number of joint replacement surgeries is on the rise. One of the most common implant materials is cobalt–chromium–molybdenum (CoCrMo) alloy. Hence, the surface properties of this alloy have attracted increasing attention. In this study, nanosecond and femtosecond laser processing, followed by annealing, was employed to modify the CoCrMo surface. The effects of the treatment conditions on the surface morphology, structure, composition, hardness, roughness, contact angle, wear properties, and corrosion current were studied. Femtosecond laser processing with an energy density of 1273 mJ/cm2, followed by heat treatment at 160 °C for 2 h, produced laser-induced periodic surface structures (LIPSS) without altering the chemical composition of the alloy and rendered the surface superhydrophobic. In contrast, nanosecond laser treatment at higher laser energy densities promoted the formation of an oxide layer, which improved the hardness and corrosion resistance of the substrate. Overall, the CoCrMo samples processed using the femtosecond laser system exhibited superior corrosion and wear resistance, with a protection efficiency of approximately 92%.

Many methods have been proposed to enhance the surface wettability of stainless steel to improve its wear and corrosion-resistant properties. However, these methods are often expensive and time-consuming. Accordingly, this study presents a straightforward approach for improving the surface wettability of 316L stainless steel using UV laser patterning at a wavelength of 355 nm, followed by heat treatment. The effects of the laser power (0.3–1.0 W), scanning speed (100–900 mm/s), heat treatment temperature (100–200 °C), and heat treatment duration (0–12 h) on the surface roughness, wettability, wear resistance, and corrosion resistance are systematically explored. The experimental results show that laser treatment at a scanning speed of 500 mm/s followed by heat treatment at 150 °C for 6 h produced a hydrophobic surface with a contact angle of 138.0°. The wear resistance of the sample was significantly improved, with a reduction in the friction coefficient from 0.075 to 0.059. The electrochemical tests showed that the hydrophobic surface reduced the corrosion current from 7.89E − 8 to 5.11E − 8 A/cm2. Overall, the optimal laser modification (1 W- 500 mm/s) and post-heat treatment (150 °C) provide an effective approach for enhancing the hydrophobicity, wear resistance, and corrosion resistance of 316L stainless steel, thereby offering an efficient alternative to existing surface modification methods.

The Ti–29Nb–13Ta–4.6Zr alloy (TNTZ) is a β-Ti alloy that has a potential for use in biomedical applications as an alternative to the less-compatible Ti64 alloys. Enhancing the strength and the surface finish of TNTZ is essential for biomedical applications. In this research, a combination of high-pressure torsion (HPT) and laser treatment was used to improve the TNTZ properties. The HPT-treated samples showed significantly enhanced mechanical properties when compared with the traditional solution-treated TNTZ. A laser surface treatment immediately forms a hydrophilic surface that transforms into a steady hydrophobic state after 14 days in air and the surface roughness increases with an increase in laser power and a slower scanning rate. The corrosion resistance of TNTZ improves significantly after laser treatment, with the corrosion current dropping from 1 × 10−8 to 1.2 × 10−9 A and the corrosion potential peak shifting to a more positive value from − 0.349 to − 0.158 V. The friction coefficient after laser treatment decreased from 0.134 to 0.093 and then further reduced to 0.082 after 14 days in air thereby suggesting an enhancement in the tribological properties. Overall, the results show that HPT processing combined with a post-HPT laser treatment is beneficial for enhancing the mechanical properties and the corrosion and wear performance of the TNTZ alloy.

The charge density wave (CDW) state is a widespread phenomenon in low-dimensional metals/semimetals. The spectral weight of the associated folded bands (shadow bands) can be an intriguing trigger leading to additional Fermi surface instability and unexplored phase transitions. The rare earth tri-telluride CeTe3 exhibits a single CDW stabilized below ~400 K and antiferromagnetism below ~3 K. The distinct periodicities between the Te-square net, the CeTe block layer, and the CDW give rise to rich shadow band formations. In this work, we reveal the predominant scattering between the original and shadow bands at 4 K, with the scattering within the original bands being relatively suppressed at Fermi energy. This unconventional quasi-particle scattering collectively underscores the vital role of the shadow bands' spectral weight and the hidden matrix element effect, which are crucial for controlling electronic properties in this system. Furthermore, our finding points to the existence of rich and unexplored Fermi surface instabilities, which potentially play a role in controlling the nature of long-range antiferromagnetism at lower temperatures in the presence of finite charge-spin interaction.

Ag thin films were deposited on glass substrates by a high vacuum sputtering system. The films were then processed by three different dewetting methods: thermal aging, pulse-laser irradiation, and two-step dewetting (thermal aging and laser irradiation). The morphologies, crystalline structures, optical properties, Raman signal intensity, and antibacterial efficiency of the dewetted Ag films were analyzed and compared. The island structures of the as-sputtered Ag film were transformed into nanoparticles as the annealing temperature increased. Furthermore, the nanoparticle size decreased with an increasing laser energy. The two-step dewetting process resulted in the formation of small nanoparticles with a narrow size distribution and a strong SPR intensity. A strong Raman peak was also observed for a 1000 ppm melamine aqueous solution deposited on the dewetted surface. The two-step dewetted film showed a better antibacterial efficiency against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa bacteria than the films processed by thermal aging or laser dewetting alone. Moreover, the two-step dewetted Ag film induced a greater ROS generation rate after contact with the Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa bacteria for 24 hr. The greater antibacterial efficiency and Raman signal intensity of the two-step dewetted film were both attributed to the effect of the small nanoparticles in increasing the contact area between the dewetted surface and the bacteria or melamine solution, respectively. Overall, the two-step dewetting process appears to be a promising approach for the fabrication of uniform small-sized nanoparticles for a wide range of applications.

In this study, an edge-removed (ER) metal-insulator-semiconductor-insulator-metal (MISIM) device is proposed for weak ambient light detection. The ER structure is employed to minimize dark current and enhance sensitivity. Also, the ER structure features the simplicity of fabrication and facilitates the removal of positive oxide charges, thereby eliminating the lateral currents induced by these charges. The simulation is also conducted to support the finding. As it comes to the advantages of the MISIM structure, it demonstrates exceptional light-sensing capabilities under both positive and negative biases. In addition, with the combination of both ER and MISIM structure, the device features a floating substrate and asymmetric concentric electrodes, achieving high sensitivity-1066 at 100 lux-while operating at a low voltage of 0.2 V, aligning with the trend toward reduced power consumption. In addition, the device maintains linearity in sensitivity across various light intensities and retains high sensitivity under low light conditions. This article concludes with benchmarks that highlight the superior performance of this device compared to other MIS-like photosensors.

Analogous to the charged electron-electron pair condensation in superconductors, an excitonic insulator (EI) represents Fermi surface instability due to spontaneous formation and condensation of charge-neutral electron-hole pair (exciton). Unlike in superconductors, however, the charge-neutral nature of exciton makes probing emergent EI phase via macroscopic physical properties generally difficult. Here, we propose a van der Waals coupled antiferromagnetic semiconductor GdGaI (GGI) as a new material category leading to emergent multi-q magnet intertwined with spontaneous exciton formation/condensation. Before excitonic band hybridization, a simple picture for the parent electronic state consists of electron (Gd-derived 5d) and hole (Ga-derived 4p) delocalized bands, together with Gd-derived 4f localized antiferromagnets with S = 7/2 classical nature. Through intra Gd atom 4f-5d Hund's coupling, a notable finding is the emergent minimum length scale (2a) Skyrmion-like spin texture resulting from spontaneous condensation/formation of spin-polarized exciton with BCS-BEC crossover phenomenology. This discovered platform is promising for realizing valuable quantum matter on the nanoscale; our finding will provide significant insight into designing the atomic scale topological magnetism out of itinerant systems.

Pure Ag nanoparticles (NPs) were synthesized on glass substrates by laser dewetting and then modified with hafnium dioxide (HfO2) by a sputtering process. The optical properties and melamine detection performance of the modified Ag NPs were investigated. The results showed that the Ag NPs produced in the laser dewetting process with accumulated unit volume energies of 0.2-3.67 kJ/mm3s had a size of 51-107 nm. Furthermore, the Ag NPs exhibited an optical absorption peak in the wavelength range of 429-495 nm. A strong Raman signal fingerprint peak was observed at 701 cm-1 in a 10-3 M melamine solution. The corresponding analytical enhancement factor (AEF) was 1.9 x 102. For the Ag@HfO2 NPs, localized surface plasmon resonance (LSPR) occurred at 584-800 nm, with an AEF of 2.3 x 104. The limit of detection for melamine using the Ag@HfO2 NPs was 10-5 M. Moreover, the Ag@HfO2 NPs showed a more stable Raman spectrum than the Ag NPs. Hence, the potential of the Ag@HfO2 NPs for melamine detection was confirmed.

Transient behavior plays a critical role in electronic devices since it represents the potential to serve as memory applications. Recently, some transient current behavior of metal-insulator-semiconductor tunnel diode (MISTD) has been demonstrated with unconventional structures [1], [2]. However, due to the usage of multiple photomasks and the process complexity at the gate edge, these devices may have scale-down issues in advanced CMOS-compatible processes. In this work, a structure of edge-removed (ER) MISTD has been proposed. Compared to previous work [2], which removes surrounding oxide and Si substrate by trench forming, the ER MISTD improves the device performance by not damaging the Si substrate. The ER MISTD can remain the same transient current window (CW) while being operated at smaller write voltage and device area. With the advantages of a smaller device area, energy-efficient operations, and the simplicity of the fabrication process, the ER MISTD is promising to serve as dynamic memory applications. The schematics of the conventional co-planar and ER MISTD are shown in Fig. 1. With the removal of the surrounding gate oxide, ER MISTD demonstrates not only lower reverse bias current but also hysteresis displacement current in Fig. 2(a) compared to planar MISTD. The leakage current of ER MISTD is 3 orders of magnitude smaller than that of planar MISTD at VG = 2V. Fig. 2(b) shows the high-frequency capacitance-voltage measurement, which demonstrates enlarged deep depletion region of the ER MISTD. We further investigated the phenomenon by Sentaurus TCAD as shown in Fig. 3. The existence of oxide charges was also adopted in simulation. The deeper depletion phenomenon of ER MISTD can be attributed to the lack of minority carriers and oxide charges without the existence of surrounding gate oxide. Another evidence of the lack of minority carriers is shown in Fig. 4. The saturation current of ER MISTD remains lower while that of planar MISTD increases and eventually induces oxide breakdown around VG = 5V. It is also found that ER MISTD isn't in oxide breakdown when VG is over 40 V as shown in the inset of Fig. 4. Next, the enhanced two-state transient current behavior has been demonstrated in Fig. 5. The specific measurement steps are shown in the inset of Fig. 5(a) and 5(b). ER MISTD has better CW in both operations compared to planar MISTD. We further investigated the mechanism of the two operations. When VG is switched from 1V to 0V, the minority carriers (𝑄𝑖𝑛𝑣) would become excess carriers since no enough time for them to be recombined. Because ER MISTD has an insufficient supply of minority carriers due to the absence of gate edge fringing field, the electron tunnel current generated by excess carriers is smaller compared to planar MISTD. With a smaller electron tunnel current to compensate for the transient discharging current, the total transient read current of ER MISTD is larger than that of planar MISTD. When VG is switched from -0.5V to 0V, the depletion region is suddenly expanded and therefore generates extra displacement current. Since the change of depletion width of ER MISTD is larger, the positive displacement current is larger as well. Because the transient current is the summation of the positive discharging current and displacement current, the transient current of ER MISTD is larger. The endurance measurement of ER MISTD has been examined as shown in Fig. 6. Fig. 6(a) shows the endurance can be tested up to 5000 cycles between 1V and 0V without much degradation. Fig. 6(b) shows the endurance between 1V and -0.5V with 102 cycles. We further investigated the CW of two operations corresponding to oxide thickness. As shown in Fig. 7, when oxide becomes thicker, the transient behavior becomes larger due to the decrease of the tunneling probability. However, the CW would eventually decay when the oxide is too thick. This is because tunnel current will disappear at thicker oxide, the transient behavior is therefore reduced. The peak value of the CW is around EOT = 3.1 nm. In conclusion, ER MISTD shows enhanced transient current and reduced leakage current due to the enlarged deep depletion. We also proposed two-state memory operations and endurance measurement of ER MISTD. The correspondence of CW and oxide thickness has been investigated as well. Because of the above characteristics, ER MISTD shows its potential to serve as a dynamic memory application. Reference: [1] Huang S -W and Hwu J -G 2021 IEEE Trans. Electron Devices 68 6580-6585 [2] Lin J -Y and Hwu J -G 2021 IEEE Trans. on Electron Devices 68 4189-4194 Figure 1

Stainless steel substrates were textured with a checkboard pattern by a NIR laser with different scan pitches and laser powers. The as-textured surfaces were found to be hydrophilic. However, after holding in air for 7-15 days, the surfaces exhibited strong superhydrophobicity with contact angles close to 150 degrees due to a reduction in the oxygen content. Thin-film Ag, Cu, Zn and Al coatings were deposited on the textured surfaces. The as-sputtered Ag and Cu films improved the hydrophobicity of the as-textured surface. However, the as-sputtered Zn and Al coatings increased the hydrophilicity. For all of the coatings, the hydrophobicity improved after aging in air for 7- 15 days. Furthermore, all of the coatings enhanced the corrosion resistance of the textured surface. Overall, the results indicate that laser texturing followed by thin-film metal deposition provides a feasible means of tuning both the wettability and the corrosion resistance of stainless steel surfaces.

AgCuAl films were deposited on glass substrates using a sputtering system. The films were dewetted using a continuous wave (CW) laser with a wavelength of 1070 nm and various settings of the laser power, duty cycle, and speed, respectively. The results showed that nanoparticles were produced for accumulated energies in the range of 0.1 - 2.2 kJ/mm3. At lower unit volume energies (0.1 - 1.3 kJ/mm3), the particles had a size of around 120 - 130 nm. However, as the accumulated energy increased to 1.7 kJ/mm3, the particle size reduced to 95 nm. The AgCuAl films produced using a duty cycle of 30 % showed an optical absorption peak wavelength in the range of 600 - 620 nm. Moreover, a blue shift was observed as the laser power increased as a result of the smaller particle size. AgCuAl nanoparticles (NPs) show a strong Raman scattering effect at 680 cm-1 in the presence of melamine solution. Hence, the feasibility of detecting melamine via surface-enhanced Raman spectroscopy was confirmed.

Bi-metal heat exchangers were fabricated by butt welding C1100 pure copper and SUS 304 stainless steel plates using two fiber laser oscillation methods (zigzag and circular). The microhardness, microstructure, and wear resistance of the weld zone were analyzed for both methods. The effects of adding single Ni, Ti, and Co interlayers and double Ni/Co interlayers to the welded joint were also investigated. The wear depth of the welded joint prepared using the circular oscillating mode was lower than that of the joint fabricated using the zigzag oscillating mode, which are 22 μm and 27 μm, respectively. Moreover, the zigzag oscillating mode increased the porosity of the weld area and hence lowered the wear resistance. The addition of a Ti interlayer prompted the formation of intermetallic compounds (IMCs) and thus enhanced the microhardness of the welding area. The sample with a pure Ti interlayer shows both the highest microhardness (> 400 HV) and the lowest wear depth (< 8 μm) and thus has the highest wear resistance. For both the single Co interlayer and the double Ni/Co interlayer, the average copper content in the weld zone increased. Among all of the interlayer welds, that containing a Ti interlayer has the highest microhardness (400 HV), the highest Cu content (51 wt

In this work, the transient current behavior of metal-insulator-semiconductor tunnel diode (MISTD) with oxide removal at the gate edge has been investigated. With an oxide-removed structure at the gate edge, the edge-removed (ER) MISTD not only exhibits reduced reverse bias current but also demonstrates enhanced transient current compared to conventional co-planar MISTD. These improved characteristics of ER MISTD can be attributed to the absence of oxide charges outside the gate edge and the insufficient supply of minority carriers. We also proposed a two-state transient current operation and tested the device’s endurance. Finally, we examined the relationship between oxide thickness and the current window and found that the current window is maximum when EOT is around 3.1 nm. Based on these properties, edge-removed MISTD shows potential as a dynamic transient memory device.

Ti-based metallic glasses have a high potential for implant applications. The feasibility of a new biocompatible Ti-based bulk metallic glass composite for selective laser melting (SLM) had been examined. Therefore, it is necessary to design a high-glass-forming-ability Ti-based metallic glass (∆Tx = 81 K, γ = 0.427, γm = 0.763), to fabricate a partial glass-formable spherical powder (the volume fraction of the amorphous phase in the atomized Ti-based powders being 73% [size < 25 μm], 61% [25–37 μm], and 50% [37–44 μm]), and establish an SLM parameter (a scan rate of 600 mm/s, a power of 120 W, and an overlap of 10%). The Ti42Zr35Si5Co12.5Sn2.5Ta3 bulk metallic glass composite was successfully fabricated through SLM. This study demonstrates that the TiZrSiCoSnTa system constitutes a promising basis for the additive manufacturing process in terms of preparing biocompatible metallic glass composites into complicated graded foam shapes.