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In this paper, the authors consider the processes that occur at the interfaces during nanowires (NWs) growth by the vapor→droplet liquid→solid mechanism (VLS), and how that leads to the faceting of the sidewall surface of the NWs. It is shown that faceting is possible only when the wetting scenario of the VLS growth of the NWs is accomplished due to the exit of the oblique closed‐packed faces to the sidewall surface of the NWs. Those oblique closed‐packed faces emerge at the crystallization front near the triple phase line. The faceting of the sidewall surface of the NWs can be controlled (i) by changing the contact angle of the catalyst droplet on the top of the NWs with the appropriate catalysts; (ii) by introducing the impurities into the gas phase, which decreases the free surface energy of the catalyst droplet; or (iii) by changing the temperature. [ABSTRACT FROM AUTHOR]

Electrochemical water‐splitting, sustained by renewable energy, is aimed at green H2 production. Efficient and sustainable electrocatalysts are required for a proper energy transition. Oxygen evolution reaction (OER) in alkaline electrolyte can be pursued by using earth‐abundant elements‐based catalysts, such as Ni oxyhydroxides. A proper optimization of intrinsic properties and synthesis procedure is still needed. Herein, the synthesis of Ni/NiO nanoparticles (NPs) through a physical and green technique, pulsed laser ablation in liquid (PLAL), is presented. Ablating a Ni target in deionized water, at different ablation times, leads to NP dispersions used for realization of OER electrode onto graphene paper. Ion‐beam analysis of catalysts amount and homogeneity of NP‐based electrode is performed for the electrode optimization in terms of electrochemical performances. An overpotential at 10 mA cm−2 of 306 mV is achieved for 40 μg cm−2 of catalyst, while lowering the catalyst amount to 8 μg cm−2, unprecedented turnover frequency of 0.20 s−1 and mass activity of ≈1.3 A mg−1 are reached. These data show that Ni/NiO NPs produced by PLAL are highly effective for OER in alkaline media and encourage the use of PLAL as a green and efficient technique for electrocatalyst production. [ABSTRACT FROM AUTHOR]

In order to achieve the attenuation of low‐frequency sound, in this paper, a hybrid metamaterial structure with a complete band gap below 500 Hz is proposed, which is subjected to second‐order fractal, series fusion, and whether the structure is framed or not to form 8 different structures. Based on the finite element method and Bloch's theorem, the bandgap and transport properties of all model structures are evaluated, and the bandgap and propagation properties of metamaterial structures with different fractal levels are elucidated in terms of band structure and group velocity. In addition, the third‐order fractal structure and the dependence of the band gap on the material are also studied. The results show that the structure has a superior band gap width, and the complete band gap of its tandem fusion structure accounts for up to 45.502% in the range of 500 Hz, and the second‐order fractal has a complete band gap of 45.588% in the range of 1000 Hz. Compared with other structures, it can produce lower and better band gap. The research in this paper provides a new strategy for realizing acoustic metamaterial structures with low frequency band gaps. [ABSTRACT FROM AUTHOR]

Neutron reflectivity (NR) was used to study the sorption of Eu(III) by graphene oxide (GO) films exposed to ethanol solution of EuCl3. Most of the earlier sorption studies have been performed using GO dispersed in solution. In contrast, layered structure of GO films imposes limitations for penetration of ions between individual sheets. The analysis of NR data recorded before and after sorption under vacuum demonstrates an increase of GO film thickness due to sorption by 35–40%. The characterization of chemical state of Eu(III) sorbed by GO films by X‐ray absorption near‐edge structure (XANES) in high‐energy resolution fluorescence detection (HERFD) method at the Eu L3 edge reveals that it remains the same as in anhydrous EuCl3. Analysis of all collected data including reference experiments with bulk GO samples allows to conclude that EuCl3 penetrates into GO interlayers with ethanol solution and remains trapped in interlayers after evaporation of ethanol. Sorption of EuCl3 results in nearly complete amorphization of film and likely formation of voids, thus making NR models based on specific volume of unit cell not valid for quantitative evaluation of Eu sorption. Limitations of NR method must be taken into account in future studies of sorption by thin films. [ABSTRACT FROM AUTHOR]

Silver nanowires (AgNW) mixed with nanocellulose nanowires (NCNW) are deposited in photolithgraphed gratings of varying depth. The nanocellulose onto which the AgNWs are mixed is of varying length. It is found that the recirculation flow is larger when the length of the NCNW is longer, and the grating used is deeper. The electrical properties of the resulting quasi‐1D electrode is tested both before it is transferred into the nanocellulose paper and after, and it is observed that it retains the same order of magnitude for the conductivities as the 0.3 and 0.2%wt concentrations for the bare AgNW. This is attributed to the use of the NCNW, at high concentrations. Using the NCNW in the mixtures allows for the AgNW to be transferred from the gratings to any substrate. Using the NC paper allows to obtain a nearly transparent or translucent nearly 1D electrode, where 1D refers to the fact the length of the obtained electrode far exceeds its width. [ABSTRACT FROM AUTHOR]

To improve the electron collection efficiency of gallium nitride (GaN) nanorod array photocathode, external electric field is used to assist collect photoelectrons and a theoretical model of field‐assisted photoelectric emission for GaN nanorod array is established herein. The results indicate that inclined incident light can improve the photoelectron collection efficiency on the side surface of the nanorod and that external electric field can promote the drifting of the photoelectron to the top surface of the nanorod. The square array with a filling fraction of 0.7 reaches its maximum photoelectron collection efficiency at the incident angle of 5° and field intensity of 0.1 V μm−1. This paper might play a theoretical guiding role in the fabrication of photodetectors with high photoelectric conversion efficiency. [ABSTRACT FROM AUTHOR]

To facilitate the calculation of the fourth‐order crystal‐field (CF) splitting moment, which in a complex way depends on the split state |J⟩, a time saving formula is elaborated, which is positively verified for several cubic systems RE3+: Cs2NaLaCl6. The appropriate crystal‐field parameters (CFPs) have to be substituted to the presented formula. However, the question is which ones. The clear answer proven in the paper is that single‐state CFPs should necessarily be used. To test the approach, a few cubic systems, for which such single‐state CFPs are available, have been studied. Conventionally fitted CFPs, averaged over the entire electron configuration, do not satisfy the equation, which contradicts the fundamental principle of the CF theory. Such verification significantly limits the physical meaning and applicability of the conventional HCF fitted parameterizations. [ABSTRACT FROM AUTHOR]

A more accurate synaptic modeling based on oxygen vacancy conductive mechanism is presented in this paper. Two internal state variables, that is, the length and area of conductive region, are used to describe the vertical and lateral growth/dissolution dynamics of the region, based on the physical mechanisms of ion drift and two different diffusion effects. Since the effect of length on the electric field is not negligible, it is introduced into the modeling. In addition, the Fick and Soret diffusions are considered, because they cause the model to produce a "forgetting" property and a "memory" retention. By the comparisons, this modeling captures the actual device better than others. In addition, the previous models can be derived from this one. Some rough analysis suggests that the modeling possibly captures different memristors by adjusting the parameters, and the effects of oxygen concentration and temperature on synapse can also be considered. Therefore, this modeling is more comprehensive and generalized. Several important synaptic functions are simulated, including excitatory postsynaptic current, paired‐pulse facilitation, spike‐rate‐dependent plasticity, and spike‐timing‐dependent plasticity, which may provide a theoretical basis for some potential applications such as artificial neural networks and artificial intelligence. [ABSTRACT FROM AUTHOR]

This is the fifteenth volume of I Physica Status Solidi B i focussed on materials and models showing negative Poisson's ratio (PR), which are often called auxetics, and other systems of unusual, e.g., "negative", characteristics. SP [ sp [1] SP ] sp This time it contains 19 papers which are grouped into three sections. This non-classical effect cannot occur in classical thermo-elasticity but is allowable in Cosserat solids. SP [ sp [17] SP ] sp Next, I Elena Pasternak and Arcady Dyskin i propose a mechanism to control the constriction of elastic rod modulus by lateral compression. This, amongst other things, opens a way to design materials ensuring vibration isolation. SP [ sp [18] SP ] sp I Haifeng Ruan and Dong Li i propose a hierarchical acoustic metamaterial with a spider-web-like structure. [Extracted from the article]

Obtaining a reliable positive‐type (p‐type) GaN semiconductor is difficult because of the unipolarity of GaN. This difficulty is one of the bottlenecks restricting the development of GaN‐based optoelectronic devices. To address this problem, this paper adopted the method of generalized gradient approximation (GGA) plane wave ultrasoft pseudopotential based on the framework of density functional theory to construct Ga35MN36, Ga34MN36, and Ga34MHiN36 (M = Be/Mg/Ca; Hi = interstitial hydrogen) models. Ga35MN35 and Ga35MHiN35 (M = Be/Mg/Ca) models were also constructed. Results of our calculations indicated that the Ga35MN35 and Ga35MHiN35 (M = Be/Mg/Ca) models cannot achieve a p‐type doping system. Furthermore, the formation energy of Ga34MN36 and Ga34MHiN36 (M = Be/Mg/Ca) systems was greater under Ga‐rich conditions than that under N‐rich conditions, indicating that both doping systems more readily formed and had a more stable structure under N‐rich conditions. Moreover, the formation energy of Ga34MHiN36 (M = Be/Mg/Ca) system was lower than that of Ga34MN36 (M = Be/Mg/Ca) system, and the existence of interstitial H proved to be beneficial to the improvement in system stability. The Ga34CaHiN36 system had the largest hole mobility and the best conductivity. Therefore, the Ga34CaHiN36 system is an ideal material for the application of conductive GaN devices. This study provides guidance into the preparation of p‐type conductive GaN materials. [ABSTRACT FROM AUTHOR]

The ICPS series traditionally encompasses a variety of topics spanning device physics, quantum technologies, spin physics, wide bandgap materials, light-matter interactions, and other branches of materials science, physics and engineering. It is my pleasure to write this preface to the Special Section in the May 2023 issue of I pss(b) i , dedicated to the collection of selected works presented during the 35 SP th sp International Conference on Physics of Semiconductors (ICPS) held in Sydney, Australia in 2022. As we are preparing for the next meeting in Ottawa, Canada, the collection of papers should inspire our junior colleagues, that not only semiconductor physics is here to stay, but in fact, it is a multi-disciplinary and burgeoning field of research. [Extracted from the article]

The valence and conduction band offset in FeNiO/CuNiO bilayer film are studied utilizing X‐ray photoelectron spectroscopy and UV–vis spectroscopy. The bilayer film is grown on Si substrate employing ion beam sputtering technique using a mixture of argon and oxygen gases at 25% oxygen partial pressure. From the precise knowledge of the valence band maxima energies and core‐level energy positions in the single‐layer film and the corresponding shifts in the bilayer film, the valence and conduction band offsets are estimated to be 0.8 and 0.3 eV, respectively. From the computed band offset data, a type‐I band alignment is identified at the interface of the grown bilayer film, which facilitates the knowledge of carrier transport mechanism and is highly attractive for the realization of efficient room‐temperature optoelectronic device. [ABSTRACT FROM AUTHOR]

This special issue "Interdisciplinary Research in Materials Science" contains a culmination of FRIMS research activities to date as well as a selection of the papers presented at the above symposium. The Frontier Research Institute for Materials Science (FRIMS) was established in 2016 as a Center of Excellence at Nagoya Institute of Technology (NITech). In this symposium that 116 scientists and students attended, FRIMS members presented their research results as the culmination of the last six years of research at FRIMS. [Extracted from the article]

Status Solidi B i B 2020 b , I 257 i , 1000755 DOI: 10.1002/pssb.201900755 Recent measurements revealed a minor error in Figure 3c of the published paper by V. V. Vogler-Neuling et al., I Phys. In the running text on page 5: "The long axis of the dipole is parallel to the orientation of the rods (cf. Solution-Processed Barium Titanate Nonlinear Woodpile Photonic Structures with Large Surface Areas. [Extracted from the article]