ISSN / EISSN : 2158-3226 / 2158-3226
Current Publisher: AIP Publishing (10.1063)Former Publisher:
Total articles ≅ 10,868
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AIP Advances, Volume 11; doi:10.1063/5.0054104
Silicon photonics enables the fabrication of optical devices with standard semiconductor processing technology. With high transparency and modal confinement, Si has matured into a well-established infrared optical material. Nanostructured silicon has been studied extensively due to its optical properties, especially silicon nanowires due to the myriad of available fabrication techniques, the broad range of physical dimensions, and the resulting optical characteristics. In this study, we fabricate silicon nanowires using a wet chemical process and modify their absorptive properties via atomic layer deposition passivation. The passivated nanowires absorb 95% of light from the visible to infrared, with a minimal angular dependence, making them excellent candidates for broadband absorber applications.
AIP Advances, Volume 11; doi:10.1063/5.0054336
Inspired by shallow-water sloshing in a moving tank, a novel type of vibration-based piezoelectric energy harvesting device composed of a piezoelectric bimorph beam and an extension tank is proposed in this paper. The structure and working principle of the proposed device are provided. Then, the effects of different heights of water filling in the tank on the performances of the harvester are studied and analyzed. Experiments are set up to investigate the actual device performance by changing the base excitation frequency and load resistance for different water heights. The results show that by modulating the water height, the resonant frequency and bandwidth can be adjusted, which can enhance the energy harvesting performance of the device at different ambient vibration frequencies. This study provides some clues to improve the performance of the vibration-based energy harvesting devices.
AIP Advances, Volume 11; doi:10.1063/5.0054236
We calculate the parameter that governs the width of the transition zone by molecular dynamics (MD) simulation and use it in a phase-field crack (PFC) simulation with the mechanical properties of iron. First, a quantitative evaluation of intactness is conducted by examining the change in atomic conformation induced by crack propagation, whose numerical data are taken from the result of the MD simulation. The spatial distribution of the intactness is fitted to the same function as the damage parameter in the PFC model, namely, an exponential function, by the least-squares method. From this distribution, the transition zone parameter is estimated. The result of the PFC simulation using this newly determined transition zone parameter is discussed in terms of the crack path by comparison with the result of crack propagation analysis based on the MD simulation.
AIP Advances, Volume 11; doi:10.1063/5.0043536
The complementary resistive switch (CRS) offers a promising logic-in-memory functionality and is a potential solution to the “von Neumann bottleneck” problem, but the CRS structure composed of two anti-serially connected bipolar resistive switching cells limits device application. In this work, we report a high-performance CRS in a single layer of ferroelectric LiTaO3 film. The device has continuous tunable steady-states, stable operating voltages, a maximum off/on ratio more than 102, good retention longer than 105 s, and a good endurance of over 107 cycles. Besides, the energy consumption of the CRS is tunable by defect engineering. Experiments suggest that the ferroelectric domain switching with charged domain walls possibly contributes to the stability of the CRS in LiTaO3 film.
AIP Advances, Volume 11; doi:10.1063/5.0051411
Corona discharge on the surface of power transmission and transformation fittings becomes increasingly serious with increasing voltage levels, especially for many grading rings in transformer substations. With the enhancement of people’s environmental awareness, the environmental protection administration requires noise and electromagnetic environment at transformer substations shall meet relevant standards. In order to suppress corona discharge on the surface of a grading ring, it is necessary to study its corona onset characteristics. Considering the basic physical process of the corona discharge, in this study, the electric field intensity is first calculated at any point in the space around the grading ring through ring charge simulation. Then, based on the theory of secondary electron emission, criteria for calculating the onset voltage of negative corona of the grading ring are derived, leading to an area factor of a photon absorption function suitable for the grading ring. In this way, a three-dimensional (3D) calculation physical model of the corona onset suitable for the grading ring is developed. This study calculates the corona onset voltage and field intensity of the grading ring under the typical working conditions by using the proposed 3D calculation physical model of the corona onset. The calculation results are compared with test results of the corona onset voltage and field intensity of grading rings in an outdoor 750 kV transformer substation in an ultrahigh voltage (UHV) alternating current (AC) test base. Furthermore, the simulation results of the area factor of the photon absorption function, electron collision coefficient, electron adsorption coefficient, and effective ionization coefficient in the 3D calculation physical model are obtained. In this way, the accuracy of the 3D calculation physical model of the corona onset proposed in this paper is verified. The research results can provide a theoretical basis for the corona prevention design of grading rings in extra high voltage/UHV AC power transmission and transformation projects.
AIP Advances, Volume 11; doi:10.1063/5.0046803
The pinning phenomena of the domain wall in the presence of exchange bias are studied analytically. The analytic solution of the domain wall spin configuration is presented. Unlike the traditional solution, which is symmetric, our new solution could exhibit the asymmetry of the domain wall spin profile. Using the solution, the domain wall position, its width, its stability, and the depinning field are discussed analytically.
AIP Advances, Volume 11; doi:10.1063/5.0053917
In this work, energy converters, which contain a GaP–Si heterojunction and Si-based Schottky barrier diodes with Al, Ti, Ag, and W, are used to convert 2 μm-thick 63Ni radioactive source energy into electrical energy. First, energy deposition distributions of the 63Ni radioactive source in these converters are simulated by using the Monte Carlo method. Then, the electrical output properties of the 63Ni/GaP–Si cell and 63Ni/metal–Si cell are determined through the numerical calculation. For the 63Ni/GaP–Si cell, with the optimized thickness of the GaP layer and doping concentration of Si, the maximum output power density and the conversion efficiency are 0.189 µW cm−2 and 1.83%, respectively. For the Si-based Schottky barrier cells with Al, Ti, Ag, and W, the 63Ni/Al–Si cell has the best electrical output properties with the same thickness of the metal layer and doping concentration of Si. When the thickness of metal Al is 0.1 µm and the doping concentration Na is 1 × 1013 cm−3, the maximum output power density and the conversion efficiency are 0.121 µW cm−2 and 1.18%, respectively. The calculation results indicate that the 63Ni/GaP–Si battery has better electrical output properties than the 63Ni/Al–Si Schottky battery. These results are valuable for fabricating practical batteries.
AIP Advances, Volume 11; doi:10.1063/5.0052518
We performed molecular dynamics simulations of the high voltage pulse explosion of single aluminum wires with the energy ratio of 0.6 in vacuum and studied the role of wire radial dimension. Simulation results show that large-diameter wires having a large material depth and a small specific surface can maintain a higher deposition energy density and effectively reduce the influence of the radial difference in thermodynamic parameters, leading to higher explosion velocity and a lower vaporization rate in the large-diameter wire. The most significant effect is that the larger diameter wire has a longer explosion development time. In addition, the propagation and reflection of the rarefaction waves in the wire result in two explosion regimes: the spinodal decomposition propagating inward from the surface and the cavitation boiling from the center to the surface. Increasing the diameter will increase the domination range of the spinodal decomposition mechanism.
AIP Advances, Volume 11; doi:10.1063/5.0047625
Developing a highly Li+-conductive thin-film electrolyte remains a challenge for the application of all-solid-state thin-film batteries. This paper reports an N-doped LiAlO2 glassy thin-film with high ionic conductivities prepared by reactive sputtering under an N2 atmosphere after the pattern of the gold standard LiPON thin-film solid electrolyte. The resulting Li+-conductive thin-film is dense without cracks and shows good adhesion to substrates. The doped N partially substitutes O and yields a triple coordination structure in the thin-films, which leads to an enhancement of ionic conductivity up to 3 orders of magnitude compared to pristine LiAlO2. On one hand, the triply coordinated nitrogen facilitates the formation of a cross-linked network and provides continuous pathways for Li+ transport. On the other hand, the triply coordinated nitrogen could provide additional hopping sites for Li+, which have a relatively weak bonding force to Li+ than O. This gives rise to an N-doped LiAlO2 thin-film with an ionic conductivity of 3.99 × 10−6 S/cm at room temperature. To the best of our knowledge, this is one of the highest ionic conductivities ever reported for LiPON-like thin-film solid electrolytes.
AIP Advances, Volume 11; doi:10.1063/5.0053946
Singlet microscopy is very attractive for the development of cost-effective and portable microscopes. In contrast to conventional microscope objectives, which consist of multiple lenses, the manufacturing process for singlet lenses is done without extensive assembling and aligning. In this manuscript, we report a novel singlet virtual Zernike phase contrast microscopy setup for unstained pathological tumor tissue slides. In this setup, the objective consists of only one lens. There is no need for the inset Zernike phase plate, which is even more expensive than a whole brightfield microscopy setup. The Zernike phase contrast is virtually achieved by the deep learning computational imaging method. For the practical virtual Zernike phase contrast microscopy setup, the computational time is less than 100 ms, which is far less than that of other computational quantitative phase imaging algorithms. With a conceptual demo experimental setup, we proved our proposed method to be competitive with a research-level conventional Zernike phase contrast microscope and effective for the unstained transparent pathological tumor tissue slides. It is believed that our deep learning singlet virtual phase contrast microscopy is potential for the development of low-cost and portable microscopes and benefits resource-limited areas.