Optical, Photo, and X‐Ray Luminescence Properties of Samarium Ions Doped with Borophosphate Glasses

Physical Review C

The measurement of direct photons from Au+ Au collisions at s N N= 39 and 62.4 GeV in the transverse-momentum range 0.4< p T< 3 Gev/c is presented by the PHENIX collaboration at the BNLRelativistic Heavy Ion Collider. A significant direct-photon yield is observed in both collision systems. A universal scaling is observed when the direct-photon p T spectra for different center-of-mass energies and for different centrality selections at s N N= 62.4 GeV is scaled with (d N ch/d η) α for α= 1.21±0.04. This scaling also holds true for direct-photon spectra from Au+ Au collisions at s N N= 200 GeV measured earlier by PHENIX, as well as the spectra from Pb+ Pb at s N N= 2760 GeV published by ALICE. The scaling power α seems to be independent of p T, center of mass energy, and collision centrality. The spectra from different collision energies have a similar shape up to p T of 2 Gev/c. The spectra have a local inverse …

Physical Review D

We report the results of a search for inelastic scattering of weakly interacting massive particles (WIMPs) off I 127 nuclei using NaI (Tl) crystals with a data exposure of 97.7 kg· years from the COSINE-100 experiment. The signature of inelastic WIMP− I 127 scattering is a nuclear recoil accompanied by a 57.6 keV γ-ray from the prompt deexcitation, producing a more energetic signal compared to the typical WIMP nuclear recoil signal. We found no evidence for this inelastic scattering signature and set a 90% confidence level upper limit on the WIMP-proton spin-dependent, inelastic scattering cross section of 1.2× 10− 37 cm 2 at the WIMP mass 500 GeV/c 2.

Physical Review D

We present results from a search for solar bosonic dark matter using the annual modulation method with the COSINE-100 experiment. The results were interpreted considering three dark sector bosons models: solar dark photons, Dine-Fischler-Srednicki-Zhitnisky (DFSZ) and Kim-Shifman-Vainshtein-Zakharov (KSVZ) solar axions, and Kaluza-Klein solar axions. No modulation signal compatible with the expected from the models was found from a dataset of 2.82 yr, using 61.3 kg of NaI (Tl) crystals. Therefore, we set a 90% confidence level upper limits for each of the three models studied. For the solar dark photon model, the most stringent mixing parameter upper limit is 1.61× 10− 14 for dark photons with a mass of 215 eV. For the DFSZ and KSVZ solar axion, and the Kaluza-Klein axion models, the upper limits exclude axion-electron couplings, g a e, above 1.61× 10− 11 for axion mass below 0.2 keV; and axion …

Radiation Physics and Chemistry

The purpose of developing high transparency radiation shielding materials and luminescence materials with stoichiometric ratio of xGd2O3:10La2O3:10ZnO:(79-x) B2O3: 1Sm2O3 where x = 0, 5, 10, 15, and 20 mol% using melt quenching technique. The physio-optical properties such as molar volume, density, concentration of rare-earth ions, polaron radius, inter-ionic radius, optical basicity, average distance between rare-earth ions, and optical packing density of the present glasses has been evaluated. The glass samples obtained show high density which is vital factor for radiation shielding. The absorption spectra show significant of bands Sm3+ ions. The FTIR results of Gd-La-Zn-B-Sm (Gd-1Sm) glass samples show signature borate BO3 and BO4 vibrational units in Gd-1Sm glass samples. The μ, μm, HVL, TVL, and MFP were evaluated and showed that the values decrease with increasing X-ray energy …

physica status solidi (a)

Various concentrations of samarium (Sm3+) ion‐activated oxyfluoroborate (ANCB:AlF3‐NaF‐CaF2‐B2O3) glasses are fabricated for its applications in red‐emitting lasers and scintillators. From the optical absorption spectrum, Ω2,4,6 intensity parameters and several radiative parameters along with the high value of absorption (2.96 × 10−21 cm2) and emission (14.13 × 10−22 cm2) cross sections are calculated. By stimulating at 403 nm, a transition corresponding to 4G5/2 → 6H7/2 (596 nm) is very intense and emits orange‐reddish luminescence of Sm3+ ion in ANCB glasses. The decay curves are fit to the Inokuti–Hirayama (I–H) model to determine the energy transfer in Sm3+: ANCB glasses. The X‐ray‐excited luminescence (XEL) spectra are determined with an X‐ray source by supplying the voltage of 50 kV and current 30 mA. The lasing parameters like stimulated emission cross section (14.13 …

Journal of Biosystems Engineering

In order to solve the shortage of roughage supply for dairy farm in Korea, winter cereal forage production after harvesting of rice in the fallow paddy field was studied. Two parts are already reported at the previous paper-One was the model development of the mechanized production, and the other was the study of feasibility of the model and its desirable direction in Korea. In this study, the model system is applied for a winter cereal wrap silage production model to practice in Kyungbook National University farm on 3ha scale for 3 years. Results of the research are summarized as followsIt takes 2 or 3 working days to process the wrap silage in middle of May in Daegu region. Also, not much particular problem can be found during the application test of mechanized wrap silage production.

physica status solidi (a)

The optical, photo, and X‐ray luminescence properties of Sm3+ ion‐doped Li2O–Al2O3–Gd2O3–B2O3–P2O5 glasses are evaluated. The glasses are fabricated by the melt quenching technique. The absorption spectra exhibit the hypersensitive transitions 6H5/2→6P3/2 and 6H5/2→6F7/2 at the visible and near‐infrared range respectively. The glasses display four major transitions characteristic of Sm3+ ion for photoluminescence and X‐ray luminescence, with the most intense one corresponding to the 4G5/2→6H7/2 transition. The best emitting samarium concentration obtained by X‐ray excitation is compared to BGO crystals. The integral scintillation efficiency of glass is determined by total area under all of peak spectrum. The results indicate the promising application of these glasses in scintillators and for X‐ray sensing devices.

Scientific Reports

The DAMA/LIBRA collaboration has reported the observation of an annual modulation in the event rate that has been attributed to dark matter interactions over the last two decades. However, even though tremendous efforts to detect similar dark matter interactions were pursued, no definitive evidence has been observed to corroborate the DAMA/LIBRA signal. Many studies assuming various dark matter models have attempted to reconcile DAMA/LIBRA’s modulation signals and null results from other experiments, however no clear conclusion can be drawn. Apart from the dark matter hypothesis, several studies have examined the possibility that the modulation is induced by variations in detector’s environment or their specific analysis methods. In particular, a recent study presents a possible cause of the annual modulation from an analysis method adopted by the DAMA/LIBRA experiment in which the observed …

Proceedings of Science

Indirect measurements from ground-based experiments have provided the all-particle spectrum from about 1014 eV to> 1020 eV. These measurements have shown that the energy spectrum above~ 3 x 1015 eV is somewhat steeper than the spectrum below, forming the so-called spectral “knee”. Whether and how the “knee” structure is related to the cosmic-ray acceleration and propagation are among the questions yet to be answered in particle astrophysics. The detailed energy dependence of elemental spectra at very high energies, where the rigidity-dependent supernova acceleration limit could be reflected in composition change, provides a key to understanding the origin, acceleration, and propagation of cosmic rays. The Cosmic Ray Energetics And Mass (CREAM) experiment was initially developed to extend direct measurements of cosmic-ray elemental spectra to the highest energy practical in a series of balloon flights [1]. Following seven successful balloon flights in Antarctica with a cumulative exposure of 191 days, the CREAM payload was transformed for the International Space Station (ISS). This version of CREAM, aka ISS-CREAM, was launched aboard a SpaceX Falcon 9 rocket as part of the 12th Commercial Resupply Service (CRS-12) mission to the ISS on August 14, 2017. Two days after launch, the Dragon spacecraft with ISS-CREAM in the unpressurized trunk arrived at the ISS. The ISS-CREAM payload was extracted from the trunk and installed on the ISS JEM-EFU# 2. Following its successful activation on the ISS on August 22, 2017, high energy cosmic ray data were taken until February 12, 2019 for 539 days.

Radiation Physics and Chemistry

In this work, Dy3+:B2O3–Ga2O3–Al2O3–Gd2O3–Y2O3 glasses system were prepared by melt quenching technique. The physical, chemical groups, optical, photoluminescence and radioluminescence properties of glasses were investigated. The density and refractive index tended to increase with increasing Dy2O3 concentration. The Dy3+ doped glasses absorbed photon in UV, VIS and NIR region in the absorption spectra. For photoluminescence study, the 276 and 351 nm wavelength owned the strong excitation peak, so they were used to measure the emission spectra. The main emission peak of Dy3+ showed at 487 and 575 nm with 4F9/2 → 6H15/2,13/2 transition due to both direct excitation and the Gd–Dy energy transfer. The luminescence lifetime of Dy3+ was in the milliseconds order that shortened with adding Dy2O3 content. The PL emission intensity at 100 K was around 1.48 times compared to its …

The European Physical Journal C

The Advanced Mo-based Rare process Experiment (AMoRE)-Pilot experiment is an initial phase of the AMoRE search for neutrinoless double beta decay of Mo, with the purpose of investigating the level and sources of backgrounds. Searches for neutrinoless double beta decay generally require ultimately low backgrounds. Surface decays on the crystals themselves or nearby materials can deposit a continuum of energies that can be as high as the Q-value of the decay itself and may fall in the region of interest (ROI). To understand these background events, we studied backgrounds from radioactive contaminations internal to and on the surface of the crystals or nearby materials with Geant4-based Monte Carlo simulations. In this study, we report on the measured energy spectra fitted with the corresponding simulated spectra for six crystal detectors, where sources of background contributions could be identified through …

Radiation Physics and Chemistry

The novel shielding materials from (55-x) SiO2: 13B2O3: 1Al2O3: 4.5BaO: 6.3CaO: 0.2Sb2O3: 20Na2O: xCeO2 where x = 1, 2, 3, 4 and 5 mol% glasses have been fabricated at different CeO2 concentration by melt-quenching technique and studied the luminescence and radiation shielding properties. The transmission spectra show red-shift in UV range, due to higher Ce concentration in the glass matrix. The emission bands of glasses around 393 nm were observed from the 5d-4f transition of an electron in the Ce3+ ion. In the present glass matrix doped with CeO2 shows oxidation state of both Ce3+ and Ce4+. Decay curves are also investigated and found to be less than 100 ns. The X-rays shielding properties such as half-value layer (HVL), tenth value layer (TVL), mean free path (MFP), and linear attenuation coefficients (μ) of glass were investigated. The HVL values of glass samples at 5 mol% has better …

Radiation Physics and Chemistry

The aim of this work is to study the radiation shielding properties in the glass systems xWO3: (70-x)Gd2O3: 30B2O3 (WGB) where x = 40, 45, 50, 55, and 60 mol%. These glasses were prepared by the melt quenching techniques. The Compton scattering technique was used to measure the experimental values of the total mass attenuation coefficient (MAC), the effective atomic number (Zeff), and the electron density (Neff) at 0.223 MeV–0.662 MeV. The measured MAC, Zeff, and Neff results were compared with the simulated and theoretical values obtained from Geant4 code and WinXcom software respectively. The comparison between the experimental, simulation and theoretical approaches for the determination of the several radiation shielding factors reflects the good detection system setup of Compton scattering experiment. The density is decreased with the increasing of WO3 concentrations from 6.1868 g/cm3 …

Scientific Reports

A novel hermetic detector composed of 200 bismuth germanium oxide crystal scintillators and 393 channel silicon photomultipliers has been developed for positronium (Ps) annihilation studies. This compact 4π detector is capable of simultaneously detecting γ-ray decay in all directions, enabling not only the study of visible and invisible exotic decay processes but also tumor localization in positron emission tomography for small animals. In this study, we investigate the use of a convolutional neural network (CNN) for the localization of Ps annihilation synonymous with tumor localization. Two-γ decay systems of the Ps annihilation from 22Na and 18F radioactive sources are simulated using a GEANT4 simulation. The simulated datasets are preprocessed by applying energy cutoffs. The spatial error in the XY plane from the CNN is compared to that from the classical weighted k-means algorithm centroiding, and the …

A scintillator, a preparation method therefor, and an application thereof are disclosed wherein the scintillator has a chemical formula of TlaAbBc: yCe, wherein: A is at least one rare earth element selected from trivalent rare earth elements; B is at least one halogen element selected from halogen elements; a= 1, b= 2 and c= 7, a= 2, b= 1 and c= 5, or a= 3, b= 1 and c= 6; and y is greater than or equal to 0 and less than or equal to 0.5. According to another embodiment, the scintillator has a chemical formula of TlaAbBc: yEu, wherein: A is an alkaline earth metal element; B is a halogen element; a= 1, b= 2 and c= 5, or a= 1, b= 1 and c= 3; and y is greater than or equal to 0 mol% and less than or equal to 50 mol%.

The current development status and future perspectives of Tl-based inorganic scintillators are highlighted in this study. The thallium (Tl) ion is known to exhibit highly efficient luminescence in the widely used NaI:Tl+, CsI:Tl+, and recently discovered Cs2Cu3I5:Tl+ scintillators. Besides being an efficient luminescence center, Tl possesses high density and atomic number, so that its presence in the host material increases the density and effective atomic number of the scintillators, which provides higher efficiencies for high-energy X- and γ-ray detection. Based on this idea, several novel efficient scintillators were reported by different research groups, which can be utilized in medical imaging, homeland security, space research, nuclear and high energy physics, rare event searches, and oil well logging. An overview of reported Tl-based scintillators and future directions for their improvements are discussed herein based …

Radiation Physics and Chemistry

Ce3+ -doped phosphate glasses with intense luminescence were reported extensively for radiation detection in recent decades. With the same intension, we fabricated glasses of composition 45P2O5:35Li2O:(10-x)GdI3:5Al2O3:5Ca2CO3:xCeBr3 (x = 1, 2, 3, 5) in molar ratio using conventional technique followed by thermal annealing. The luminescence studies confirmed the energy transfer process from Gd3+ to Ce3+ -ions. The scintillation measurements of the optimized sample were performed under the excitation of α -particles and γ-rays. A photopeak was detected under γ-ray excitation at 662 keV energy from 137Cs source. The estimated absolute light yield was 1600 ± 200 Photons/MeV. The shortest component of the decay time under α -particles and γ -ray excitations was found 32.5 ± 0.3 ns and 39.9 ± 0.4 ns, respectively. In the future, the glass configuration can be engineered to improve radiation …

The Astrophysical Journal

The Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) experiment successfully recorded data for 539 days from 2017 August to 2019 February. We report the energy spectrum of cosmic-ray protons from the ISS-CREAM experiment at energies from 1.60× 10 3 to 6.55× 10 5 GeV. The measured spectrum deviates from a single power law. A smoothly broken power-law fit to the data, including statistical and systematic uncertainties, shows the spectral index change at 9.0× 10 3 GeV from 2.57±0.03 to 2.82±0.02 with a significance of greater than 3σ. This bump-like structure is consistent with a spectral softening recently reported by the balloon-borne CREAM, DAMPE, and NUCLEON, but ISS-CREAM extends measurements to higher energies.

Journal of Instrumentation

The COSINE-100 experiment is designed to test the DAMA experiment which claimed an observation of a dark matter signal from an annual modulation in their residual event rate. To measure the 1%-level signal amplitude, it is crucial to control and monitor nearly all environmental quantities that might systematically mimic the signal. The environmental monitoring also helps ensure a stable operation of the experiment. Here, we describe the design and performance of the centralized environmental monitoring system for the COSINE-100 experiment.

physica status solidi (a)

While ferroelectric HfO2 shows promise for use in memory technologies, limited endurance is one factor that challenges its widespread application. Herein, endurance is investigated through field cycling W/Hf0.5Zr0.5O2/W capacitors above the coercive field while manipulating the time under field using bipolar pulses of varying pulse duration or duty cycle. Both remanent polarization and leakage current increase with increasing pulse duration. Additionally, an order of magnitude decrease in the pulse duration from 20 to 2 μs results in an increase in endurance lifetime of nearly two orders of magnitude from 3 × 106 to 2 × 108 cycles. These behaviors are attributed to increasing time under field allowing for charged oxygen vacancy migration, initially unpinning domains, or driving phase transformations before segregating to grain boundaries and electrode interfaces. This oxygen vacancy migration causes …

physica status solidi (a)

Herein, a digital–analog hybrid resistive random‐access memory (RRAM) is prepared by integrating the structurally similar SiNx‐based digital‐type RRAM with analog‐type RRAM by heterogeneous integration method. The Pt/SiNx/Ta/Ru is a digital RRAM due to the formation and breakage of the internal silicon dangling bonds conductive filaments, and the TiN/SiNx/Ta/Ru structure is an analog RRAM due to the traps‐filled limit region of the space‐charge limited current. The heterogeneously integrated digital RRAM has good cycling stability and endurance characteristics, and the heterogeneously integrated analog RRAM has high linearity and multistate counting characteristics. This heterogeneous integration approach is useful for the implementation of hybrid digital–analog RRAM.

physica status solidi (a)

Photoinduced (PI) evolution of statistically rough surfaces of amorphous chalcogenide films As20Se80 at room temperature has been studied by measuring the angular dependence of the intensity of light scattered from a surface illuminated by CW laser (λ = 660 nm). The interpretation of the scattering data based on the resonant scattering theory enables to confirm unequivocally the diffusion mechanism of PI mass transfer. It is detected that the change of the amplitude of a spatial harmonic in the roughness spectra strongly depends on its period ∧ . During illumination, the amplitude increases at ∧ > ∧*, whereas harmonics with ∧ < ∧* decreases by ∧*, which corresponds to zero evolution rate, is found to be 6.7 μm. In accordance with our theoretical prediction, both growth and decrease are exponential with the rates depending on ∧. As the result, the roughness with initial rms height of 50–70 nm …

physica status solidi (a)

Electrostatic potentials strongly affect molecular energy levels and charge states, providing the fascinating opportunity of molecular gating. Their influence on molecular vibrations remains less explored. Here, we investigate ethyl‐diaminodicyanoquinone molecules on a monolayer of MoS2 on Au(111) using scanning tunneling and atomic force microscopy and spectroscopy. These molecules exhibit a large dipole moment in gas phase, which is found to (partially) persist on the MoS2 monolayer. The self‐assembled structures consist of chains, where the dipoles of neighboring molecules are aligned antiparallel. Thanks to the decoupling efficiency of the molecular states from the metal by the MoS2 interlayer, vibronic states of the molecules are resolved, which vary in intensity depending on the molecular surrounding. We suggest that the vibrations are strongly damped by electrostatic interactions with the …

physica status solidi (a)

Transition metal dichalcogenides (TMDCs) are a promising class of two‐dimensional (2D) materials for flexible electronic applications due to their low integration temperature, good electronic properties, and excellent mechanical flexibility. Moreover, TMDCs offer the possibility of co‐integrating both n‐ and p‐type transistors on the same substrate, enabling the realization of complementary metal‐oxide‐semiconductor (CMOS) circuits. In this study, n‐type MoS2 field‐effect transistors (FETs), and p‐type WSe2‐FETs integrated on a flexible foil substrate fabricated by standard thin‐film technology are presented. These devices exhibit high stability in their electronic operation under strain and repeated bending cycles. A CMOS inverter based on these transistors is also successfully demonstrated, which shows excellent switching behaviour with high gain (up to 100), high noise margin (0.87 · VDD), and low average …

physica status solidi (a)

Rationalizing material features according to the adopted synthetic strategy, aiming then to tune them on demand, is among the most relevant purposes of investigation in materials science. Herein, the systematic analysis of the dependence of graphitic carbon nitride (g‐C3N4) physical characteristics on the decomposition temperature of urea, rationalizing the impact of synthetic temperature on several characteristics of the materials (degree of N–H condensation, carbon vs nitrogen content, structural parameters, photoluminescence lifetime, surface area, pores volume), is discussed. g‐C3N4 nanostructures are fabricated by thermal decomposition of urea at different temperatures under ambient atmosphere, obtaining an almost ideal stoichiometry (C/N = 0.72) when setting the temperature at 600 °C. The samples show structural, textural, compositional, and optical differences directly depending on the fabrication …

physica status solidi (a)

The aim of this article is to show that it is possible to rapidly estimate the activation energies of electron traps in AlInN/GaN transistors operating at room temperature by combining pulsed electrical measurements with photoionization techniques using infrared illumination. This technique avoids the time‐consuming task of performing electrical measurements at different temperatures to determine the activation energies of the electron traps using Arrhenius laws. Thus, a deep level at 1.3 eV is detected and attributed to the presence of carbon in GaN buffer of the component. Moreover, we have highlighted that the trapping effect can be screened when the transistors are biased with a high drain‐source voltage during pulsed measurements.

physica status solidi (a)

Herein, a tunnel‐current‐driven plasmonic nanoantenna for the generation of single photons is proposed. The proposal uses two constituents: 1) small gold nanoparticles that feature Coulomb blockade already at room temperature combined with an 2) self‐similar nanorod arrangement. The Coulomb blockade allows for single‐plasmon generation and the nanorod arrangement for an efficient transformation into photons. As the emission from such an electrically driven antenna follows its spectral scattering response, the color of single photons can be tuned by geometrical changes of the antenna over an extremely broad range far into the infrared. The calculations suggest high photon purities, repetition rates beyond, and efficiencies comparable to ordinary single‐photon sources based on emitters like color centers or heralded single‐photon sources, respectively. Given recent achievements in the field and the …

physica status solidi (a)

To ensure good water quality, microbiological contamination in water must be detected. This process is made easier and more distinctive using a photonic crystal fiber (PCF), which offers outstanding optical sensing capabilities. Herein, a PCF sensor model is proposed for detecting two types of waterborne bacteria, namely, Vibrio cholera and Escherichia coli bacteria. The core region of the proposed PCF sensor is made up of a single rectangle and the cladding region has 32 rectangular air holes that have the same height and width as the core rectangle. Zeonex is employed as the fiber material. Using Comsol 5.6 which is based on the finite‐element method, the model is numerically analyzed and structured. The simulation verifies the effectiveness of the proposed PCF to detect the analyte samples. Numerous performance indicators are calculated at an operating 2.8 THz. Simulation results show that the …

physica status solidi (a)

Herein, the authors investigate the temperature‐dependent properties of delayed luminescence in an as‐grown nitrogen‐containing chemical vapor deposition synthetic diamond gemstone when excited above its bandgap. At room temperature, this gemstone exhibits delayed luminescence from nitrogen‐vacancy centers at 575 nm. However, at 77 K, the first recorded instance of a long‐lived delayed blue luminescence centered at ≈465 nm, accompanied by spectral peaks at 419, 455, and 499 nm is reported. By analyzing spectral and temporal data at different temperatures, it can be speculated on potential photophysical transitions. This discovery documents the initial observation of this delayed luminescence emission, contributing to the collective understanding of synthetic diamonds.

physica status solidi (a)

Optically active color centers in diamonds have been intensively studied due to their potential in photonics, energy harvesting, biosensing, and quantum computing. Silicon vacancy (SiV) center offers an advantage of suitable emission wavelength and narrow zero‐phonon line at room temperature. Measurement of surface potential and photovoltage can provide better understanding of the physics and control of SiV light emission, such as charge states and charging effects. Herein, optoelectronic properties of nanocrystalline diamond films with SiV centers at different layer thicknesses (10–200 nm, controlled by the growth time) under ambient conditions are studied. Time‐dependent measurements are performed in the light–dark–light cycle. Positive photovoltage arises on samples with SiV layer thicknesses below 55 nm on both H‐ and O‐terminated surfaces. Above 55 nm the photovoltage switches to negative …

physica status solidi (a)

Effects of the ultrathin 1 nm thick AlGaN regrown layer before gate insulator deposition on the performance of ZrO2/AlGaN/GaN metal‐insulator‐semiconductor (MIS) structures are investigated. In comparison with the reference ZrO2/AlGaN/GaN MIS high‐electron‐mobility transistors (MIS‐HEMTs), MIS‐HEMTs with AlGaN regrown layer exhibit increased maximum drain current (>1050 mA mm−1) and broader full‐width at half maximum (FWHM) of transconductance profile (11 V). Moreover, the gate leakage current in the forward direction is reduced by about four orders of magnitude while the hysteresis of the transfer curves is cut‐down to more than 40%. Compared with the control MIS‐capacitors (MIS‐caps), MIS‐caps with regrowth show highly evident sudden increase in capacitance known as “spill‐over” in the capacitance–voltage (C–V) profiles, suggesting improved ZrO2/AlGaN interfaces. Extracted …

physica status solidi (a)

Recent progress in growth techniques has enabled the fabrication of stacks of transition metal dichalcogenide monolayers combined with different nanostructures ranging from other 2D layers over dye molecules to even plasmonic nanoparticles. Such structures promise to combine the optoelectric properties of the constituents allowing to design structures with desired properties. For all of these examples, a detailed knowledge of the coupling among different constituents is crucial. In this article, a unified description is presented based on Maxwell Bloch equations to describe dipolar interactions among different types of heterostructures. Exemplary, Förster‐type energy transfer from dye molecules to MoS2 monolayers, strong coupling at MoSe2–metal nanoparticle interfaces, Meitner–Auger‐like interlayer coupling in WSe2–graphene stacks, and relaxation processes of hot interlayer excitons in MoSe2–WSe2 …

physica status solidi (a)

Photonic circuits attract much attention as promising candidates to overcome the drawbacks of their electronic counterparts. By utilizing the broad bandwidth and low energy consumption of optical communication, hybrid circuits can provide a comprehensive platform for the era beyond Moore's law. In particular, parallel matrix operations, the heavy lifting behind neural networks, remain challenging for traditional electronics due to high heat dissipation. To enable these parallel computations optically, (de‐)multiplexing is crucial to address the different channels. Previously this has been accomplished with complex spectral or time encodings in wave division or time division methods. However, herein, a simple method to address parallel optical channels exclusively with 2‐bit signals is presented. By using PEDOT:PSS as electrochromic material for intensity modulation, light transmission or absorption is controlled by …

physica status solidi (a)

The realization of the potential of hybrid inorganic organic systems requires an understanding of the coupling between the constituents: its nature and its strength. The observation of hybrid optical transitions in the monolayer WS2/terrylene hybrid is reported. The first‐principle calculations, linear optical, and transient absorption spectroscopy are employed to investigate the optical spectrum of the hybrid, which exhibits a new transition that does not appear in the constituents’ spectra. The calculations indicate type II level alignment, with the highest occupied level of terrylene in the gap of WS2. Exploiting state‐resolved transient absorption, the response of the hybrid interface to optical excitation is selectively probed. The dynamics reveal rapid hole transfer from WS2 to the terrylene layer, with a decay time of 88 ps. This hole transfer induces a bleach of the hybrid transition, which indicates that terrylene contributes to …

physica status solidi (a)

Effects of the ultrathin 1 nm thick AlGaN regrown layer before gate insulator deposition on the performance of ZrO2/AlGaN/GaN metal‐insulator‐semiconductor (MIS) structures are investigated. In comparison with the reference ZrO2/AlGaN/GaN MIS high‐electron‐mobility transistors (MIS‐HEMTs), MIS‐HEMTs with AlGaN regrown layer exhibit increased maximum drain current (>1050 mA mm−1) and broader full‐width at half maximum (FWHM) of transconductance profile (11 V). Moreover, the gate leakage current in the forward direction is reduced by about four orders of magnitude while the hysteresis of the transfer curves is cut‐down to more than 40%. Compared with the control MIS‐capacitors (MIS‐caps), MIS‐caps with regrowth show highly evident sudden increase in capacitance known as “spill‐over” in the capacitance–voltage (C–V) profiles, suggesting improved ZrO2/AlGaN interfaces. Extracted …

physica status solidi (a)

Electrostatic potentials strongly affect molecular energy levels and charge states, providing the fascinating opportunity of molecular gating. Their influence on molecular vibrations remains less explored. Here, we investigate ethyl‐diaminodicyanoquinone molecules on a monolayer of MoS2 on Au(111) using scanning tunneling and atomic force microscopy and spectroscopy. These molecules exhibit a large dipole moment in gas phase, which is found to (partially) persist on the MoS2 monolayer. The self‐assembled structures consist of chains, where the dipoles of neighboring molecules are aligned antiparallel. Thanks to the decoupling efficiency of the molecular states from the metal by the MoS2 interlayer, vibronic states of the molecules are resolved, which vary in intensity depending on the molecular surrounding. We suggest that the vibrations are strongly damped by electrostatic interactions with the …

physica status solidi (a)

Cover image provided courtesy of Zeyu Zhang and John E. Bowers from Electrical and Computer Engineering Department, University of California Santa Barbara. The cover art showcases a novel photonic integration platform that monolithically integrates lasers on silicon photonic chip, presented initially in article 2100522.

physica status solidi (a)

Anodic Nb–Ti oxide crossbar memristor arrays are successfully produced on Si substrates. Their use as pH sensors is tested by analyzing their current–voltage (I–U) sweeps in Ringer´s solutions with different pH values. A gradual evolution of the memristive hysteretic curve is observed upon pH variation. A sensor calibration showing a linear trend with least square error close to 1 is performed and the performance of the pH sensing is assessed. The limit of detection (LOD), limit of quantification (LOQ), and the sensitivity (S) are determined. The calculated LOD is 0.4 pH, and the LOQ is 1.2 pH. The S is calculated as 0.5 pH corresponding to a concentration of c(OH−) = 3.5 mM. The reproducibility and repeatability of the measurements are calculated as 3.8% and 1.4%, respectively. An X‐ray photoelectron spectroscopy survey allows the study of the oxide composition providing information about its pH‐sensing …

physica status solidi (a)

This article presents a new mathematical model for simulating the power conversion efficiency (PCE) of organic solar cells (OSCs) and perovskite solar cells (PSCs). This model incorporates all power losses that can occur before the charge carriers are collected by their respective electrodes. This includes power loss due to thermalization of the charge carriers above the bandgap (PThermal$P_{\text{Thermal}}$), charge carrier recombination (Prec)$P_{\text{rec}} \left.\right)$, dissociation of excitons (PBI)$P_{\text{BI}} \left.\right)$, and the transport of free charge carriers to their respective electrodes through the energy off‐sets (PB)$P_{\text{B}} \left.\right)$. By quantifying each power loss, the model can simulate the net electrical power generated by a solar cell and estimate its PCE. The validity of the mathematical model is tested by comparing the calculated PCE of an OSC and a PSC with their experimental results …