Inspired by valley pseudospins in two-dimensional materials, high-quality-factor (high-Q) spin–valley states were created through the photonic Rashba-type spin splitting of a bound state in the continuum. This approach enabled the construction of a coherent and controllable spin-optical laser using monolayer-integrated spin–valley microcavities without requiring magnetic fields or cryogenic temperatures.

To elucidate the internal chemical physics of measured CMOS-compatible electrochemical random-access memory (ECRAM) devices, we constructed a 2D semiconductor device simulation, including ions and electrochemical reactions, and used it to fit measured devices. We present the results of a device simulation model that includes Cu⁺ ions’ diffusion and the charge transfer reaction between the WO_x conduction band electron and Cu⁺ (i.e., “Cu plating”). Reproducing the linear response of ECRAM devices, the effect of charging HfO_x by the Cu⁺ ions is sufficient, and WO_x is not being doped by the Cu⁺ ions. While potentiation is supported by the formation of an electron channel, an efficient depression requires the formation of high positive charge density at the channel material. At higher Cu⁺ flux, Cu⁺ reaches and penetrates the WO_x layer. While this effect enhances the potentiation response, it also initiates the “plating” reactions. Including this reaction is essential to reproducing the data of devices exhibiting sub-linear responses. We suggest that electron trapping by ions (i.e., plating) would constitute a long-term degradation process even for H⁺ based devices.

The extensive and improper use of antibiotics has led to a dramatic increase in the frequency of antibiotic resistance among human pathogens, complicating infectious disease treatments. In this work, a method for rapid antimicrobial susceptibility testing (AST) is presented using microstructured silicon diffraction gratings integrated into prototype devices, which enhance bacteria-surface interactions and promote bacterial colonization. The silicon microstructures act also as optical sensors for monitoring bacterial growth upon exposure to antibiotics in a real-time and label-free manner via intensity-based phase-shift reflectometric interference spectroscopic measurements (iPRISM). Rapid AST using clinical isolates of Escherichia coli (E. coli) from urine is established and the assay is applied directly on unprocessed urine samples from urinary tract infection patients. When coupled with a machine learning algorithm trained on clinical samples, the iPRISM AST is able to predict the resistance or susceptibility of a new clinical sample with an Area Under the Receiver Operating Characteristic curve (AUC) of ∼ 0.85 in 1 h, and AUC > 0.9 in 90 min, when compared to state-of-the-art automated AST methods used in the clinic while being an order of magnitude faster.

Transition metal oxides (TMOs) exhibit a broad spectrum of electronic, magnetic, and optical properties, making them intriguing materials for various technological applications. Soft x-ray absorption spectroscopy (XAS) is widely used to study TMOs, shedding light on their chemical state, electronic structure, orbital polarization, element-specific magnetism, and more. Different XAS acquisition modes feature different information depth regimes in the sample. Here, we employ two XAS acquisition modes, having surface-sensitive versus bulk probing depths, on the prototypical TMO SrVO3. We illustrate and elucidate a strong apparent discrepancy between the different modes, emphasizing the impact of the near-surface region on the interpretation of XAS data. These findings highlight the importance of the acquisition mode selection in XAS analysis. Moreover, the results highlight the role of the near-surface region not only in the characterization of TMOs, but also in the design of future nanoscale oxide electronics.

Biomaterial-centered infections of orthopedic implants remain a significant burden in the healthcare system due to a sedentary lifestyle and an aging population. One approach to combat infections and improve implant osteointegration is functionalizing the implant surface with anti-infective and osteo-inductive agents. In this framework, Au nanoparticles are produced on the surface of Ti-6Al-4V medical alloy by solid-state dewetting of 5 nm Au film and used as the substrate for the conjugation of a model antibiotic vancomycin via a mono-thiolated poly(ethylene glycol) linker. Produced Au nanoparticles on Ti-6Al-4V surface are equiaxed with mean diameter ~20 nm, which is shown by high-resolution scanning microscopy. The conjugation of the antibiotic vancomycin, ~10-15 nm film, is confirmed by high resolution-scanning transmission electron microscopy and X-ray photoelectron spectroscopy. Overall, our results demonstrate the simplicity, versatility, and modularity of the proposed method for functionalization of implant surfaces.

Direct-bandgap transition metal dichalcogenide monolayers are appealing candidates to construct atomic-scale spin-optical light sources owing to their valley-contrasting optical selection rules. Here we report on a spin-optical monolayer laser by incorporating a WS₂ monolayer into a heterostructure microcavity supporting high-Q photonic spin-valley resonances. Inspired by the creation of valley pseudo-spins in monolayers, the spin-valley modes are generated from a photonic Rashba-type spin splitting of a bound state in the continuum, which gives rise to opposite spin-polarized ±K valleys due to emergent photonic spin–orbit interaction under inversion symmetry breaking. The Rashba monolayer laser shows intrinsic spin polarizations, high spatial and temporal coherence, and inherent symmetry-enabled robustness features, enabling valley coherence in the WS₂ monolayer upon arbitrary pump polarizations at room temperature. Our monolayer-integrated spin-valley microcavities open avenues for further classical and non-classical coherent spin-optical light sources exploring both electron and photon spins.

A solar cell device is presented. The solar cell device comprises a layered structure comprising an electron transport layer and a hole transport layer and a heterojunction interface region between the electron transport and hole transport layers configured to define at least one charge generation region forming at least one junction between them, wherein at least one of the electron transport layer and the hole transport layer comprises at least one modulated doping layer at a predetermined distance from said at least one junction, said at least one modulated doping layer thereby inducing variation of an energy band structure at a vicinity of said at least one junction generating electric field applied to charge carriers increasing efficiency of generation and/or collection of the charge carriers.

Silicon photonics is an emerging platform for acoustic sensing, offering exceptional miniaturization and sensitivity. While efforts have focused on silicon-based resonators, silicon nitride resonators can potentially achieve higher Q-factors, further enhancing sensitivity. In this work, a 30 µm silicon nitride microring resonator was fabricated and coated with an elastomer to optimize acoustic sensitivity and signal fidelity. The resonator was characterized acoustically, and its capability for optoacoustic tomography was demonstrated. An acoustic bandwidth of 120 MHz and a noise-equivalent pressure of ∼ 7 mPa/Hz^1/2 were demonstrated. The spatially dependent impulse response agreed with theoretical predictions, and spurious acoustic signals, such as reverberations and surface acoustic waves, had a marginal impact. High image fidelity optoacoustic tomography of a 20 µm knot was achieved, confirming the detector’s imaging capabilities. The results show that silicon nitride offers low signal distortion and high-resolution optoacoustic imaging, proving its versatility for acoustic imaging applications.

We study recombination pathways in halide perovskite solar cells using a semiconductor device model that includes iodide diffusion and iodide reactions. We stress the device at a bias of 0.9 V, close to the maximum power point, and compare blocking layers impermeable to ions and those that allow ionic transport. For both cases, we examine the impact of incorporating iodide reactions. By comparing stress under dark and one sun excitation conditions, we find that the photoexcited charges enable the redistribution of iodide, which in the case of permeable blocking layers results in the deterioration of the power conversion efficiency and the appearance of hysteresis. If all the reactions are reversible and there is no loss of iodine, their main effect is the introduction of mobile recombination centres. Introducing reactive electrodes that react with and immobilise the iodide results in a rapid loss of performance on the time scale of an hour, which is only slightly accelerated under illumination. We also find that under light excitation, there is a generation of iodine molecules (I₂). If the I₂ is allowed to leave the device, this constitutes a slow (1000s of hours), but non-reversible degradation pathway. Encouragingly, a judicial choice of the electron-blocking layer's energy levels could suppress this degradation path.

In Mott materials strong electron correlation yields a spectrum of complex electronic structures. Recent synthesis advancements open realistic opportunities for harnessing Mott physics to design transformative devices. However, a major bottleneck in realizing such devices remains the lack of control over the electron correlation strength. This stems from the complexity of the electronic structure, which often veils the basic mechanisms underlying the correlation strength. This study presents control of the correlation strength by tuning the degree of orbital overlap using picometer-scale lattice engineering. This study illustrates how bandwidth control and concurrent symmetry breaking can govern the electronic structure of a correlated SrVO₃ model system. This study shows how tensile and compressive biaxial strain oppositely affect the SrVO₃ in-plane and out-of-plane orbital occupancy, resulting in the partial alleviation of the orbital degeneracy. The spectral weight redistribution under strain is derived and explained, which illustrates how high tensile strain drives the system toward a Mott insulating state. Implementation of such concepts can push correlated electron phenomena closer toward new solid-state devices and circuits. These findings therefore pave the way for understanding and controlling electron correlation in a broad range of functional materials, driving this powerful resource for novel electronics closer toward practical realization.