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Interlayer excitons (ILXs) — electron–hole pairs bound across two atomically thin layered semiconductors — have emerged as attractive platforms to study exciton condensation 1 – 4 , single-photon emission and other quantum information applications 5 – 7 . Yet, despite extensive optical spectroscopic investigations 8 – 12 , critical information about their size, valley configuration and the influence of the moiré potential remains unknown. Here, in a WSe 2 /MoS 2 heterostructure, we captured images of the time-resolved and momentum-resolved distribution of both of the particles that bind to form the ILX: the electron and the hole. We thereby obtain a direct measurement of both the ILX diameter of around 5.2 nm, comparable with the moiré-unit-cell length of 6.1 nm, and the localization of its centre of mass. Surprisingly, this large ILX is found pinned to a region of only 1.8 nm diameter within the moiré cell, smaller than the size of the exciton itself. This high degree of localization of the ILX is backed by Bethe–Salpeter equation calculations and demonstrates that the ILX can be localized within small moiré unit cells. Unlike large moiré cells, these are uniform over large regions, allowing the formation of extended arrays of localized excitations for quantum technology. Imaging the electron and hole that bind to form interlayer excitons in a 2D moiré material enables direct measurement of its diameter and indicates the localization of its centre of mass.

We investigate the vibrational and magnetic properties of thin layers of chromium tribromide (CrBr 3 ) with a thickness ranging from three to twenty layers (3–20 L) revealed by the Raman scattering (RS) technique. Systematic dependence of the RS process efficiency on the energy of the laser excitation is explored for four different excitation energies: 1.96 eV, 2.21 eV, 2.41 eV, and 3.06 eV. Our characterization demonstrates that for 12 L CrBr 3 , 3.06 eV excitation could be considered resonant with interband electronic transitions due to the enhanced intensity of the Raman-active scattering resonances and the qualitative change in the Raman spectra. Polarization-resolved RS measurements for 12 L CrBr 3 and first-principles calculations allow us to identify five observable phonon modes characterized by distinct symmetries, classified as the A g and E g modes. The evolution of phonon modes with temperature for a 16 L CrBr 3 encapsulated in hexagonal boron nitride flakes demonstrates alterations of phonon energies and/or linewidths of resonances indicative of a transition between the paramagnetic and ferromagnetic state at Curie temperature ( T C ≈ 50  K). The exploration of the effects of thickness on the phonon energies demonstrated small variations pronounces exclusively for the thinnest layers in the vicinity of 3–5 L. We propose that this observation can be due to the strong localization in the real space of interband electronic excitations, limiting the effects of confinement for resonantly excited Raman modes to atomically thin layers.

Introduction Zolpidem (ZPD) is a non-benzodiazepine sedative indicated for the treatment of insomnia. ZPD exhibits sex differences in pharmacokinetics, and females have higher systemic exposure than males. The recommended dose is 5 mg for women and 10 mg for men. The reduction in dose for females might be insufficient to produce the desired therapeutic efficacy. Hence, the dose adjustment is required to ensure the safety and efficacy of the therapy, especially in females. Objective The pharmacokinetics of ZPD were studied using the physiologically based pharmacokinetic model (PBPK) using covariates such as sex, body weight, and clearance with the objective of dose adjustment in females using virtual bioequivalence (VBE) studies. Methods The modeling and simulation were performed using Gastroplus 9.8.3 software. Various models published in the literature were screened. The selected model was modified and validated using intravenous and oral pharmacokinetic data. Three in silico VBE trials were carried out using males as a test and females as reference groups. The reference groups of females consist of three covariates such as weight, weight normalized, and clearance with weight normalized data. The rest of the validated model parameters were kept constant. Results The prediction errors of developed models were high (> 20%) for peak plasma drug concentration ( C max ) and well within the limit for the area under the plasma drug concentration curve (AUC) in body weight normalized in female subjects with male subjects. Young females have 20% lower body weight when compared to males, and hence higher systemic exposure resulted in females due to body weight. The clearance rate was lesser in females when compared with males. However, higher CYP3A4-mediated metabolism was observed in females than in males. Moreover, there is no significant difference in systemic drug exposure (92.7% vs 104% AUC 0–i ) due to the lower clearance rate in females. Conclusion The results obtained from virtual bioequivalence data suggest that the dose adjustment for females according to their body weight could be beneficial. Normal-weight females could be recommended with a 30% lower dose and overweight females with a normal dose of 10 mg. Graphical Abstract

Graphene, which is a planar or 2D allotrope of carbon, is actually the building block of graphite. Graphene has potential applications in many fields, such as highfrequency field-effect transistors, flexible electronics, touch panels, optoelectronic devices, energy storage devices, and wearable technology. Despite such promise, most of the graphene-based applications to date are limited to either theoretical work or laboratory research. This is due to the many challenges related to fabrication of graphene-based devices. Continuous graphene is a necessity for many electrical and optical applications. These applications, however, are built upon substrates that are not suitable for graphene growth. As a result, graphene must be transferred from its growth substrate (usually Cu foil) to a different substrate (such as a silicon wafer). Transfer techniques often introduce defects in graphene, such as wrinkles, cracks, and voids or holes. To address this problem, we developed a wet graphene transfer method in which we add a copolymer to poly(methyl methacrylate) (PMMA) prior to transfer. Unlike previously reported wet methods, we show that adding a copolymer layer atop a PMMA layer before transfer improves graphene continuity by virtually eliminating cracks and holes. The result, as determined by quantitative image analysis, is 99.8% continuous graphene over a 1 cm × 1 cm area. In addition to its many unique electronic properties, graphene can sustain THz-frequency plasmons at room temperature. In an attempt to exploit this property for THz communication, we have demonstrated a hybrid graphene–metal reflectarray structure. In this reflectarray, the active elements are metal and graphene reduces the reflected power by destroying the confinement. Lastly, we investigate all-graphene plasmonic antenna arrays, and propose an array of suspended graphene regions to realize plasmonic resonant cavities.

We investigate the vibrational and magnetic properties of thin layers of chromium tribromide (CrBr ) with a thickness ranging from three to twenty layers (3-20 L) revealed by the Raman scattering (RS) technique. Systematic dependence of the RS process efficiency on the energy of the laser excitation is explored for four different excitation energies: 1.96 eV, 2.21 eV, 2.41 eV, and 3.06 eV. Our characterization demonstrates that for 12 L CrBr , 3.06 eV excitation could be considered resonant with interband electronic transitions due to the enhanced intensity of the Raman-active scattering resonances and the qualitative change in the Raman spectra. Polarization-resolved RS measurements for 12 L CrBr and first-principles calculations allow us to identify five observable phonon modes characterized by distinct symmetries, classified as the A and E modes. The evolution of phonon modes with temperature for a 16 L CrBr encapsulated in hexagonal boron nitride flakes demonstrates alterations of phonon energies and/or linewidths of resonances indicative of a transition between the paramagnetic and ferromagnetic state at Curie temperature (  K). The exploration of the effects of thickness on the phonon energies demonstrated small variations pronounces exclusively for the thinnest layers in the vicinity of 3-5 L. We propose that this observation can be due to the strong localization in the real space of interband electronic excitations, limiting the effects of confinement for resonantly excited Raman modes to atomically thin layers.

We investigate the vibrational and magnetic properties of thin layers of chromium tribromide (CrBr\\(_3\\)) with a thickness ranging from three to twenty layers (3~L to 20~L) revealed by the Raman scattering (RS) technique. Systematic dependence of the RS process efficiency on the energy of the laser excitation is explored for four different excitation energies: 1.96 eV, 2.21 eV, 2.41 eV, and 3.06 eV. Our characterization demonstrates that for 12 L CrBr\\(_3\\), 3.06~eV excitation could be considered resonant with interband electronic transitions due to the enhanced intensity of the Raman-active scattering resonances and the qualitative change in the Raman spectra. Polarization-resolved RS measurements for 12 L CrBr\\(_3\\) and first-principles calculations allow us to identify five observable phonon modes characterized by distinct symmetries, classified as the A\\(_\\textrm{g}\\) and E\\(_\\textrm{g}\\) modes. The evolution of phonon modes with temperature for a 20 L CrBr\\(_3\\) encapsulated in hexagonal boron nitride flakes demonstrates alterations of phonon energies and/or linewidths of resonances indicative of a transition between the paramagnetic and ferromagnetic state at Curie temperature (\\(T_\\textrm{C} \\approx 50\\) K). The exploration of the effects of thickness on the phonon energies demonstrated small variations pronounces exclusively for the thinnest layers in the vicinity of 3 - 5 L. This observation is attributed to strong localization in the real space of interband electronic excitations, limiting the effects of confinement for resonantly excited Raman modes to atomically thin layers.

Heterostructures (HSs) formed by the transition-metal dichalcogenides (TMDCs) materials have shown great promise in next-generation optoelectronic and photonic applications. An artificially twisted HS, allows us to manipulate the optical, and electronic properties. With this work, we introduce the understanding of the complex energy transfer (ET) process governed by the dipolar interaction in a twisted molybdenum diselenide (MoSe2) homobilayer without any charge-blocking interlayer. We fabricated an unconventional homobilayer (i.e., HS) with a large twist angle by combining the chemical vapor deposition (CVD) and mechanical exfoliation (Exf.) techniques to fully exploit the lattice parameters mismatch and indirect/direct (CVD/Exf.) bandgap nature. This effectively weaken the charge transfer (CT) process and allows the ET process to take over the carrier recombination channels. We utilize a series of optical and electron spectroscopy techniques complementing by the density functional theory calculations, to describe a massive photoluminescence enhancement from the HS area due to an efficient ET process. Our results show that the electronically decoupled MoSe2 homobilayer is coupled by the ET process, mimicking a 'true' heterobilayer nature.

High light absorption (~15%) and strong photoluminescence (PL) emission in monolayer (1L) transition metal dichalcogenide (TMD) make it an ideal candidate for optoelectronic applications. Competing interlayer charge (CT) and energy transfer (ET) processes control the photocarrier relaxation pathways in TMD heterostructures (HSs). In TMDs, long-distance ET can survive up to several tens of nm, unlike the CT process. Our experiment shows that an efficient ET occurs from the 1Ls WSe2-to-MoS2 with an interlayer hBN, due to the resonant overlapping of the high-lying excitonic states between the two TMDs, resulting in enhanced HS MoS2 PL emission. This type of unconventional ET from the lower-to-higher optical bandgap material is not typical in the TMD HSs. With increasing temperature, the ET process becomes weaker due to the increased electron-phonon scattering, destroying the enhanced MoS2 emission. Our work provides new insight into the long-distance ET process and its effect on the photocarrier relaxation pathways.

Type-II heterostructures (HSs) are essential components of modern electronic and optoelectronic devices. Earlier studies have found that in type-II transition metal dichalcogenide (TMD) HSs, the dominating carrier relaxation pathway is the interlayer charge transfer (CT) mechanism. Here, this report shows that, in a type-II HS formed between monolayers of MoSe2 and ReS2, nonradiative energy transfer (ET) from higher to lower work function material (ReS2 to MoSe2) dominates over the traditional CT process with and without a charge-blocking interlayer. Without a charge-blocking interlayer, the HS area shows 3.6 times MoSe2 photoluminescence (PL) enhancement as compared to the MoSe2 area alone. After completely blocking the CT process, more than one order of magnitude higher MoSe2 PL emission was achieved from the HS area. This work reveals that the nature of this ET is truly a resonant effect by showing that in a similar type-II HS formed by ReS2 and WSe2, CT dominates over ET, resulting in a severely quenched WSe2 PL. This study not only provides significant insight into the competing interlayer processes, but also shows an innovative way to increase the PL quantum yield of the desired TMD material using ET process by carefully choosing the right material combination for HS.

Resolving the momentum degree of freedom of excitons - electron-hole pairs bound by the Coulomb attraction in a photoexcited semiconductor, has remained a largely elusive goal for decades. In atomically thin semiconductors, such a capability could probe the momentum forbidden dark excitons, which critically impact proposed opto-electronic technologies, but are not directly accessible via optical techniques. Here, we probe the momentum-state of excitons in a WSe2 monolayer by photoemitting their constituent electrons, and resolving them in time, momentum and energy. We obtain a direct visual of the momentum forbidden dark excitons, and study their properties, including their near-degeneracy with bright excitons and their formation pathways in the energy-momentum landscape. These dark excitons dominate the excited state distribution - a surprising finding that highlights their importance in atomically thin semiconductors.