The semiconductor industry is facing significant challenges, including physical limitations such as heat dissipation, rising manufacturing costs, and the difficulty of further shrinking transistor sizes while maintaining performance. To address these issues, chiplet technology has emerged, integrating smaller, specialized chips into a single package. This approach improves modularity, manufacturing yields, and allows mixing different technology nodes for optimal performance. However, challenges like ensuring high-speed, low-latency interconnects and effective thermal management persist.This study explores several key aspects of chiplet technology using a simplified dual-chip model, focusing on the integration of nanocopper materials. By comparing nanocopper with traditional solder, we analyze differences in mechanical behavior and thermal management. Additionally, we investigate variations in chiplet layout, examining the impact of spacing and the number of chiplets on performance under identical power conditions. Our findings indicate that nanocopper interconnects provide lower stress and better thermal conductivity than traditional solder. Adjusting chiplet spacing and increasing the number of chiplets both enhance heat dissipation. Future work will involve larger-scale simulations and fatigue analyses to optimize chiplet packaging for improved performance and reliability.

Particle morphology is a critical structural variable in pressure-assisted sintering because it controls packing, pore topology, interparticle bonding and load transfer. Here, copper (Cu) was used as a model system to examine how monomodal spherical, bimodal spherical and flake-shaped particle assemblies, processed under identical conditions, form porous structures with distinct mechanical responses. Micro-pillar compression reveals low effective elastic moduli of 7.5–12.5 GPa and high yield strengths of 403–450 MPa. The deformation pathways are strongly morphology dependent. The monomodal structure accommodates strain through distributed pore collapse and particle deformation, leading to progressive densification hardening. The bimodal structure exhibits size-partitioned deformation, with large particles forming the main load-bearing backbone and smaller particles accommodating local rearrangement, embedding and shear compaction. The flake-shaped structure undergoes geometry-guided deformation, where extended face-to-face bonding enhances local load bearing, while inter-flake misalignment concentrates strain and promotes shear localization. Post-compression transmission electron microscopy (TEM) and transmission Kikuchi diffraction (TKD) analyses link these modes to pore collapse, neck deformation and grain-scale strain accommodation. TKD further gives average Geometrically Necessary Dislocations (GND) densities of 4.36×10¹⁴ m⁻², 3.69×10¹⁴ m⁻² and 4.11×10¹⁴ m⁻² for the monomodal, bimodal and flake-shaped structures, respectively. Molecular dynamics (MD) simulations reproduce the corresponding strain-localization patterns and reveal morphology-controlled load-transfer pathways dominated by Shockley partial dislocations. These results establish particle morphology as a design parameter for tuning stiffness, strength and damage tolerance in sintered porous metals.

This study investigates the size-dependent mechanical behavior and deformation mechanisms of sintered copper (Cu) nanoparticles (NPs) through micro-pillar (2–6 μm diameter) compression tests, scanning electron microscopy (SEM), transmission electron microscopy (TEM), transmission Kikuchi diffraction (TKD) analysis and molecular dynamics (MD) simulations. In-situ micro-pillar compression tests reveal a 25.9% reduction in yield strength (812 ± 64 MPa to 643 ± 47 MPa) with increasing pillar size, attributed to dislocation starvation in smaller pillars and porosity-driven strain localization in larger ones. TKD quantifies dynamic grain refinement (24.9% reduction in grain size) and geometrically necessary dislocation (GND) density escalation (74.8%), driven by stress gradients and grain boundary-mediated plasticity. Nanoindentation-derived elastic modulus (48.3 ± 11.1 GPa) exceeds micropillar values (29.5–33.9 GPa), reflecting substrate constraints in bulk testing. Microstructural analysis identifies a transition from shear banding in high-porosity pillars to uniform plasticity in denser systems, mediated by texture evolution (Brass/S components) and Schmid factor redistribution (62% increase in high-slip-activity grains). MD simulations of pressure-sintered Cu NPs elucidate atomic-scale mechanisms: dislocation nucleation at sintering necks, pore collapse-induced strain localization, and grain boundary sliding. These findings establish a multiscale framework linking porosity, grain refinement, and dislocation dynamics to mechanical performance, emphasizing microstructural optimization for enhanced reliability in microelectronic applications. The integration of MD simulations bridges atomic-scale mechanisms to microscale deformation, providing actionable insights for tailoring sintered Cu NPs via reduced porosity and controlled grain boundary architectures.

This study introduces a novel strategy for fabricating flexible nitrogen dioxide (NO₂) gas sensors based on Indium Oxide (In₂O₃) nanoparticles (NPs) employing selective reduction laser sintering (SRLS) technology. The SRSL technology utilizes ultraviolet (UV) laser selective reduction sintering to precisely and rapidly create oxygen vacancy (OV) defects in In₂O₃ NPs. These oxygen vacancies (OVs) enhance the active adsorption sites and contribute additional free electrons, significantly improving sensor performance at room temperature. The sensors demonstrate excellent response (S = 460.9 at 10 ppm), rapid response/recovery times (τ_resp/τ_reco = 27/570 s), and superior selectivity (response ratio > 400), in addition to robust resistance to light and humidity (under ppm-level NO₂ gas). The sensors also exhibit a low detection limit (200 ppb), a high signal-to-noise ratio (94.8 dB), and good long-term stability (25 days). Moreover, under photo-assisted conditions, the recovery speed of the sensors is further improved. This technology not only provides an innovative strategy for the development of high-performance flexible NO₂ gas sensors but also broadens the application potential of laser direct writing (LDW) technology in advanced materials and sensor fabrications.

Flexible strain sensors based on nanomaterials have sparked a lot of interest in the field of wearable smart electronics. Laser induced graphene (LIG) based sensors in particular stand out due to their straightforward fabrication procedure, three-dimensional porous structures, and exceptional electromechanical capabilities. Recent studies have focused on LIG composites, however, it is still difficult to achieve great sensitivity and excellent linearity in a wide linear working range. Herein, a strain sensor with high sensitivity and good linearity is prepared in this work, which was realized by carbonizing the polyimide film coated with HfSe₂ to obtain three-dimensional porous graphene nanosheets decorated with HfSe₂ (HfSe₂/LIG). After being transferred to the flexible substrate of Ecoflex, it exhibits high stretchability, hydrophobicity and robustness, and obtains excellent electromechanical properties. The HfSe₂/LIG strain sensor demonstrated high sensitivity (gauge factor, GF ≈ 46), a low detection limit (0.02%), good linearity (R² = 0.99) in a large working range (up to 30%), and a quick response time (0.20 s). Additionally, it exhibits good stability and consistent behavior across a large number of strain/release test cycles (>3000 cycles). With these benefits, the sensor can be used to monitor various limb movements (including finger, wrist and neck movements) and minute artery activity, and can generate reliable signals. Therefore, the HfSe₂/LIG-based sensor has enormous potential for use in wearable intelligent electronics and movement monitoring.

In recent years, metal crack-based stretchable flexible strain sensors have attracted significant attention in wearable device applications due to their extremely high sensitivity. However, the tradeoff between sensitivity and detection range has been an intractable dilemma, severely limiting their practical applications. Herein, we propose a laser transmission pyrolysis (LTP) technology for fabricating high-performance flexible strain sensors based on (Au) metal cracks with the microchannel array on the polydimethylsiloxane (PDMS) surface. The fabricated flexible strain sensors exhibit high sensitivity [gauge factor (GF) of 2448], wide detection range (59% for tensile strain), precise strain resolution (0.1%), fast response and recovery times (69 and 141 ms), and robust durability (over 3000 cycles). In addition, experiment and simulation results reveal that introducing a microchannel array enables the stress redistribution strategy on the sensor surface, which significantly improves the sensing sensitivity compared to conventional flat surface sensors. Based on the excellent performance, the sensors are applied to detect subtle physiological signals, such as pulse and swallowing, as well as to monitor large-scale motion signals, such as knee flexion and finger bending, demonstrating their potential applications in health monitoring, human-machine interactions, and electronic skin.

Nano copper sintering technology has great potential to be widely applied in the wide-bandgap semiconductor packaging. In order to investigate the coalescence kinetics of copper nano particles for this application, a molecular dynamic (MD) simulation was carried out at low temperature on a special model containing two substrate and multiple particles in between. Accordingly, thorough microstructure and dislocation investigation was conducted to identify the atomic-scale evolution in the system. The corresponding findings could provide evidence on the new particle-substrate sintering mechanism. Furthermore, atomic trajectories tracking method was applied to study the rotation behavior of different sized nano particles. New rotation behavior and mechanism were described. Additionally, the study on the size effect of copper particles on the sintering process and coalescence mechanism was conducted via comparing the microstructural and dislocation distribution of 3 nm, 4 nm and 5 nm models. Finally, by comparing the MSD results at low and high temperature for each model, the dominant coalescence dynamics changes were obtained.

For the relevant properties of pristine and doped (Si, P, Se, Te, As) monolayer WS₂ before and after the adsorption of CO, CO₂, N₂, NO, NO₂ and O₂, density functional theory (DFT) calculations are made. Calculation results reveal that the monolayer WS₂ doped with P and As atoms can be substrate materials for NO and NO₂ gas sensors. However, after the subsequent CDD and ELF calculations, it is found that P-doped monolayer WS₂ adsorbs NO and NO₂ in a chemical way, while As-doped monolayer WS₂ adsorbs NO and NO₂ in a physical way. Also, the charge transfer between As-doped monolayer WS₂ and NO is relatively small and not easily detected. Besides, As-doped monolayer WS₂ system exhibits greater differences in optical properties (the imaginary part of reflectivity and dielectric function) before and after the adsorption of NO₂ gas than before and after adsorption of NO gas. These differences in optical properties assist sensor devices in making gas adsorption-related judgments. Through the analysis of the recovery time, DOS and PDOS, As-doped monolayer WS₂ is also verified to be a promising NO₂ sensing material, whose recovery time is calculated to be as short as 0.169 ms at 300 K.

The development of high-performance gas sensing materials is one of the development trends of new gas sensor technology. In this work, in order to predict the gas-sensitive characteristics of HfSe₂ and its potential as a gas-sensitive material, the interactions of nonmetallic element (O, S, Te) doped HfSe₂ monolayer and small molecules (NH₃ and O₃) have been studied by first-principles based on density functional theory. The results show that the adsorption of NH₃ and O₃ on pristine HfSe₂ monolayer is weak, and the adsorption strength can be significantly improved by doping O. And O-HfSe₂ is chemical adsorption to O₃ with large adsorption energy and transfer charge, and the band gap of O[sbnd]HfSe₂ disappears after adsorbing O₃, indicating that the adsorption of O₃ has a significant effect on the electrical properties of the substrate. These mean that O₃ is difficult to recover from the substrate surface, thus preventing O-HfSe₂ from developing into a sensitive material for O₃ detection. After doping S, the charge transfers and adsorption strength to NH₃ are the largest, but it is still small. So, the strain effect on the S-HfSe₂/NH₃ adsorption system is also studied. The results indicate that the adsorption strength of S-HfSe₂ to NH₃ can be enhanced by stretching S-HfSe₂ along x-axis. After absorbing NH₃, the conductivity of x-axis strained S-HfSe₂ changes, which suggest its sensitivity. And the predicted recovery times of S-HfSe₂ surfaces with ε_x=4%, 6% and 8% are 0.027 s, 1.153 s and 102.467 s, respectively, which suggests that the S-HfSe₂ monolayer has the potential to be developed as a sensitive material for NH₃ detection. These adsorption mechanism studies can also serve as a theoretical foundation for the experimental design of gas-sensing materials.

The authors regret that one of the affiliations (affiliation f) was incorrectly omitted in the original manuscript. The corrected list of affiliations is as shown below. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

In this paper, tin oxidation (SnO x )/tin-sulfide (SnS) heterostructures are synthesized by the post-oxidation of liquid-phase exfoliated SnS nanosheets in air. We comparatively analyzed the NO2 gas response of samples with different oxidation levels to study the gas sensing mechanisms. The results show that the samples oxidized at 325 °C are the most sensitive to NO2 gas molecules, followed by the samples oxidated at 350 °C, 400 °C and 450 °C. The repeatabilities of 350 °C samples are better than that of 325 °C, and there is almost no shift in the baseline. Thus this work systematically analyzed the gas sensing performance of SnO x/SnS-based sensor oxidized at 350 °C. It exhibits a high response of 171% towards 1 ppb NO2, a wide detecting range (from 1 ppb to 1 ppm), and an ultra-low theoretical detection limit of 5 ppt, and excellent repeatability at room temperature. The sensor also shows superior gas selectivity to NO2 in comparison to several other gas molecules, such as NO, H2, SO2, CO, NH3, and H2O. After X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscope, and electron paramagnetic resonance characterizations combining first principle analysis, it is found that the outstanding NO2 sensing behavior may be attributed to three factors: The Schottky contact between electrodes and SnO x/SnS; active charge transfer in the surface and the interface layer of SnO x/SnS heterostructures; and numerous oxygen vacancies generated during the post-oxidation process, which provides more adsorption sites and superior bandgap modulation. Such a heterostructure-based room-temperature sensor can be fabricated in miniaturized size with low cost, making it possible for large-scale applications.

In this work, the adsorption of toxic gaseous NO₂ and other gas molecules (NO, CO, CO₂, N₂, O₂, SO₂) on pristine and X-doped (X = Si, P, S, Te, As) two-dimensional (2D) WSe₂ have been detailed studied by performing density functional theory (DFT) calculations. Calculation results of adsorption energies and adsorption distances demonstrate that As-doped 2D WSe₂ (As-WSe₂) exhibits high selectivity not only towards NO₂, but also towards NO and SO₂. However, the charge transfer between NO and the substrate is too small to detect, and chemical bond forms between SO₂ and the substrate; both phenomena make As-WSe₂ substrate more suitable as a substrate material of the NO₂ sensor. To eliminate the interference of SO₂ on the adsorption of NO₂, coexistence of NO₂ and SO₂ is simulated. Results reveal that although the interaction between SO₂ and the As-WSe₂ substrate is stronger than that between NO₂ and the substrate, SO₂ molecule hardly interacts with the substrate when co-adsorbed with NO₂. Besides, calculation results of DOS and PDOS further confirm the sensitivity of As-WSe₂ towards NO₂; and those of the recovery time also highlight the extremely fast recovery rate of As-WSe₂ after adsorbing NO₂. The present findings make As-WSe₂ monolayer a potential substrate material of NO₂ gas sensors used in the atmospheric environment.