ACS Applied Materials & Interfaces最新文献

Two-dimensional transition-metal dichalcogenide (TMD) homojunctions are promising for optoelectronic applications but are fundamentally limited by inefficient carrier separation, even under reverse bias. Here, we introduce surface acoustic wave (SAW) technology as an efficient means to enhance photocarrier dissociation via strain-mediated electron-phonon interactions. To experimentally validate this approach, we constructed a hybrid acoustooptic platform by integrating a LiNbO₃ substrate with interdigitated transducers onto a SiO₂/Si chip. A reconfigurable WSe₂ homojunction─fabricated on an hexagonal boron nitride (h-BN) intermediate layer and dynamically tunable via UV-assisted doping to form junctions with tailored built-in potentials─served as the functional device. Under SAW excitation propagating from LiNbO₃ into the device stack, the homojunction exhibits a 30% photocurrent enhancement at 550 nm illumination, outperforming conventional reverse-bias operation at nearly an order-of-magnitude lower voltage, while maintaining a rectification ratio of >10³ and negligible dark-current variation. Mechanistic studies reveal that the SAW induces a type-I band modulation in the nonpiezoelectric heterostructure, creating energy barriers that suppress recombination and substantially improve electron-hole separation. This work demonstrates SAW as an effective strategy for enhancing the optoelectronic performance in homojunctions and provides a scalable platform for acoustooptic applications in nonpiezoelectric low-dimensional systems.

The rapid advancement of 5G communication technology necessitates enhanced performance in electromagnetic interference (EMI) shielding and thermal management materials. We fabricated multifunctional nacre-like MXene@CuNPs(MSC)composite films via intermittent filtration and in situ reduction. The resulting composite film exhibited a high in-plane thermal conductivity of 47.6 W m^-1 K^-1 and demonstrated superior thermal management capability in heat dissipation tests. Containing 3.1 wt % Cu and with a thickness of 0.04 mm, the film achieved an average EMI shielding effectiveness (SE) of 64 dB within the X-band (8.2-12.4 GHz). Calculations based on the effective medium theory (EMT) elucidated the critical role of Cu nanoparticles (CuNPs) in establishing an efficient thermal conduction network. Owing to the CuNPs acting as thermal bridges, the interfacial thermal resistance within the composite film decreased by 35.6%. Furthermore, the MSC composite films exhibited rapid-response photothermal behavior. Upon irradiation with a light power density of 200 mW cm^-2, the surface temperature of the MSC_3.1 film rapidly reached 101 °C. The outstanding performance of this composite film underscores the broad application potential of Cu-modified MXene in electronic devices and related fields.

Ruthenium (Ru) has emerged as a promising next-generation metal for ultrahigh-density interconnects, offering superior electrical performance and electromigration resistance at submicrometre dimensions, and thus is a strong candidate to replace Cu in future very-large-scale integration (VLSI) technologies. However, enabling Ru/dielectric hybrid bonding at low temperatures remains exceedingly challenging. The intrinsically high melting point of Ru(∼2334 °C) and its extremely low diffusion coefficient (∼1 × 10^-70 m²·s^-1) typically necessitate high-temperature, high-pressure thermal compression bonding. In parallel, hydrophilic bonding with dielectric materials such as SiO₂ must be achieved while suppressing Ru surface oxidation. In this study, we introduce a synergistic surface-activation strategy─Ar/H₂ plasma treatment followed by immersion in NH₄OH─that enables robust Ru-Ru bonding at 250 °C without oxidation. Moreover, the activated surfaces yield a 20% reduction in Ru surface resistance. This approach generates abundant -OH and -NH₂ functional groups on the Ru surface, promoting interfacial reactions and the formation of a void-free interface. Intriguingly, the bond strengths exceeded 12 MPa after 1000 thermal cycles between -45 °C and +125 °C. This synergistic activation route provides a viable pathway for low-temperature Ru/dielectric hybrid bonding with high reliability. The demonstrated bonding performance underscores Ru potential as a Cu replacement in BEOL interconnects and establishes a foundation for metal/dielectric hybrid bonding in forthcoming high-density integration technologies.

Lithium metal batteries have gained renewed attention after a recent surge in high-energy battery systems. Lithium metal, known for its exceptional specific capacity and voltage, suffers from dendrite formation, which affects the cell performance and poses a severe safety threat, like internal short circuits and thermal runaway. Artificial solid electrolyte (ASEI) has emerged as an effective strategy to guide uniform lithium deposition, but only a few studies have explored the correlation between the interfacial kinetics and the nucleation behavior at the molecular level. In our work, we developed an inorganic-organic hybrid bilayer protective coating on the lithium anode, enabling over 1000 h of Li/Li symmetric cell cycling at 0.5 mA/cm² (0.5 mAh/cm²) with low overpotentials. The impact of this bilayer on the nucleation behavior has been addressed using chronoamperometric studies and a modified SEI model based on S-H classical nucleation. Ab initio molecular dynamics (AIMD) simulations revealed the role of bilayer components in homogenizing the lithium flux by decreasing the coordination number of lithium ions and promoting lateral growth. These led to a relatively uniform lithium deposition morphology with better capacity retention of more than 80% after 80 cycles for protected lithium (p-Li)/NMC-622 half-cells cycled at 1.7 C with a high loading of 23 mg/cm². Our findings establish the importance of interface engineering in controlling the nucleation kinetics of lithium deposition for the development of high-voltage lithium metal batteries.

In this work, an in-depth correlated study of the impact of grain boundaries on the excitonic and electronic properties of monolayer WS₂ is reported. Signatures of defect- and strain-induced gap states are detected and studied in the vicinity of the grain boundaries using tip-enhanced photoluminescence, Kelvin probe force microscopy, and conductive atomic force microscopy. These gap states demonstrate a trap-like behavior for the free excitons, resulting in the radiative recombination of the localized excitonic states at room temperature. The trapping behavior is also detected for the free carriers, indicated by the abundance of fixed charges at the grain boundaries. The carrier trapping is corroborated through (tip-enhanced) photoluminescence spectroscopy at the grain boundaries, particularly after photoinjection of carriers. Comparison of the photoluminescence response acquired under ambient and high vacuum indicates the high reactivity of these defect sites and physisorption of ambient species. The ambient molecules seemingly passivate the defect sites and locally modulate the layer properties.