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<jats:p>We numerically solve the time-dependent Ginzburg–Landau equations for two-gap superconductors using the finiteelement technique. The real-time simulation shows that at low magnetic field, the vortices in small-size samples tend to form clusters or other disorder structures. When the sample size is large, stripes appear in the pattern. These results are in good agreement with the previous experimental observations of the intriguing anomalous vortex pattern, providing a reliable theoretical basis for the future applications of multi-gap superconductors.</jats:p>

<jats:p>Hysteresis loops, energy products and magnetic moment distributions of perpendicularly oriented Nd<jats:sub>2</jats:sub>Fe<jats:sub>14</jats:sub>B/<jats:italic>α</jats:italic>-Fe exchange-spring multilayers are studied systematically based on both three-dimensional (3D) and one-dimensional (1D) micromagnetic methods, focused on the influence of the interface anisotropy. The calculated results are carefully compared with each other. The interface anisotropy effect is very palpable on the nucleation, pinning and coercive fields when the soft layer is very thin. However, as the soft layer thickness increases, the pinning and coercive fields are almost unchanged with the increment of interface anisotropy though the nucleation field still monotonically rises. Negative interface anisotropy decreases the maximum energy products and increases slightly the angles between the magnetization and applied field. The magnetic moment distributions in the thickness direction at various applied fields demonstrate a progress of three-step magnetic reversal, i.e., nucleation, evolution and irreversible motion of the domain wall. The above results calculated by two models are in good agreement with each other. Moreover, the in-plane magnetic moment orientations based on two models are different. The 3D calculation shows a progress of generation and disappearance of vortex state, however, the magnetization orientations within the film plane calculated by the 1D model are coherent. Simulation results suggest that negative interface anisotropy is necessarily avoided experimentally.</jats:p>

<jats:p>Y-type hexaferrites with tunable conical magnetic structures are promising single-phase multiferroics that exhibit large magnetoelectric effects. We have investigated the influence of Co substitution on the magnetoelectric properties in the Y-type hexaferrites Ba<jats:sub>0.3</jats:sub>Sr<jats:sub>1.7</jats:sub>Co<jats:sub> <jats:italic>x</jats:italic> </jats:sub>Mg<jats:sub>2−<jats:italic>x</jats:italic> </jats:sub>Fe<jats:sub>12</jats:sub>O<jats:sub>22</jats:sub> (<jats:italic>x</jats:italic> = 0.0, 0.4, 1.0, 1.6). The spin-induced electric polarization can be reversed by applying a low magnetic field for all the samples. The magnetoelectric phase diagrams of Ba<jats:sub>0.3</jats:sub>Sr<jats:sub>1.7</jats:sub>Co<jats:sub> <jats:italic>x</jats:italic> </jats:sub>Mg<jats:sub>2−<jats:italic>x</jats:italic> </jats:sub>Fe<jats:sub>12</jats:sub>O<jats:sub>22</jats:sub> are obtained based on the measurements of magnetic field dependence of dielectric constant at selected temperatures. It is found that the substitution of Co ions can preserve the ferroelectric phase up to a higher temperature, and thus is beneficial for achieving single-phase multiferroics at room temperature.</jats:p>

<jats:p>Based on the surface passivation of n-type silicon in a silicon drift detector (SDD), we propose a new passivation structure of SiO<jats:sub>2</jats:sub>/Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>/SiO<jats:sub>2</jats:sub> passivation stacks. Since the SiO<jats:sub>2</jats:sub> formed by the nitric-acid-oxidation-of-silicon (NAOS) method has good compactness and simple process, the first layer film is formed by the NAOS method. The Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> film is also introduced into the passivation stacks owing to exceptional advantages such as good interface characteristic and simple process. In addition, for requirements of thickness and deposition temperature, the third layer of the SiO<jats:sub>2</jats:sub> film is deposited by plasma enhanced chemical vapor deposition (PECVD). The deposition of the SiO<jats:sub>2</jats:sub> film by PECVD is a low-temperature process and has a high deposition rate, which causes little damage to the device and makes the SiO<jats:sub>2</jats:sub> film very suitable for serving as the third passivation layer. The passivation approach of stacks can saturate dangling bonds at the interface between stacks and the silicon substrate, and provide positive charge to optimize the field passivation of the n-type substrate. The passivation method ultimately achieves a good combination of chemical and field passivations. Experimental results show that with the passivation structure of SiO<jats:sub>2</jats:sub>/Al<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub>/SiO<jats:sub>2</jats:sub>, the final minority carrier lifetime reaches 5223 μs at injection of 5×10<jats:sup>15</jats:sup> cm<jats:sup>−3</jats:sup>. When it is applied to the passivation of SDD, the leakage current is reduced to the order of nA.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>A new crystal growth theoretical model is established for the low-dimensional nanocrystals on an isotropic and quasi-free sustained substrate. The driven mechanism of the model is based on the competitive growth among the preferential growth directions of the crystals possessing anisotropic crystal structures, such as the hexagonal close-packed and wurtzite structures. The calculation results are in good agreement with the experimental findings in the growth process of the low-dimensional Zn nanocrystals on silicone oil surfaces. Our model shows a growth mechanism of various low-dimensional crystals on/in the isotropic substrates.</jats:p>

<jats:p>Hafnium disulfide (HfS<jats:sub>2</jats:sub>) is a promising two-dimensional material for scaling electronic devices due to its higher carrier mobility, in which the combination of two-dimensional materials with traditional semiconductors in the framework of CMOS-compatible technology is necessary. We reported on the deposition of HfS<jats:sub>2</jats:sub> nanocrystals by remote plasma enhanced atomic layer deposition at low temperature using Hf(N(CH<jats:sub>3</jats:sub>)(C<jats:sub>2</jats:sub>H<jats:sub>5</jats:sub>))<jats:sub>4</jats:sub> and H<jats:sub>2</jats:sub>S as the reaction precursors. Self-limiting reaction behavior was observed at the deposition temperatures ranging from 150 °C to 350 °C, and the film thickness increased linearly with the growth cycles. The uniform HfS<jats:sub>2</jats:sub> nanocrystal thin films were obtained with the size of nanocrystal grain up to 27 nm. It was demonstrated that higher deposition temperature could enlarge the grain size and improve the HfS<jats:sub>2</jats:sub> crystallinity, while causing crystallization of the mixed HfO<jats:sub>2</jats:sub> above 450 °C. These results suggested that atomic layer deposition is a low-temperature route to synthesize high quality HfS<jats:sub>2</jats:sub> nanocrystals for electronic device or electrochemical applications.</jats:p>

<jats:p>The GaN thick films have been grown on porous GaN template and planar metal-organic chemical vapor deposition (MOCVD)-GaN template by halide vapor phase epitaxy (HVPE). The analysis results indicated that the GaN films grown on porous and planar GaN templates under the same growth conditions have similar structural, optical, and electrical properties. But the porous GaN templates could significantly reduce the stress in the HVPE-GaN epilayer and enhance the photoluminescence (PL) intensity. The voids in the porous template were critical for the strain relaxation in the GaN films and the increase of the PL intensity. Thus, the porous GaN converted from <jats:italic>β</jats:italic>-Ga<jats:sub>2</jats:sub>O<jats:sub>3</jats:sub> film as a novel promising template is suitable for the growth of stress-free GaN films.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>This paper presents a new silicon-on-insulator (SOI) lateral-double-diffused metal-oxide-semiconductor transistor (LDMOST) device with alternated high-<jats:italic>k</jats:italic> dielectric and step doped silicon pillars (HKSD device). Due to the modulation of step doping technology and high-<jats:italic>k</jats:italic> dielectric on the electric field and doped profile of each zone, the HKSD device shows a greater performance. The analytical models of the potential, electric field, optimal breakdown voltage, and optimal doped profile are derived. The analytical results and the simulated results are basically consistent, which confirms the proposed model suitable for the HKSD device. The potential and electric field modulation mechanism are investigated based on the simulation and analytical models. Furthermore, the influence of the parameters on the breakdown voltage (BV) and specific on-resistance (<jats:italic>R</jats:italic> <jats:sub>on, sp</jats:sub>) are obtained. The results indicate that the HKSD device has a higher BV and lower <jats:italic>R</jats:italic> <jats:sub>on, sp</jats:sub> compared to the SD device and HK device.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We present a method to extend the operating wavelength of the interband transition quantum well photodetector from an extended short-wavelength infrared region to a middle-wavelength infrared region. In the modified InAsSb quantum well, GaSb is replaced with AlSb/AlGaSb, the valence band of the barrier material is lowered, the first restricted energy level is higher than the valence band of the barrier material, the energy band structure forms type-II structure. The photocurrent spectrum manifest that the fabricated photodetector exhibits a response range from 1.9 μm to 3.2 μm with two peaks at 2.18 μm and 3.03 μm at 78K.</jats:p>

<jats:p>The impacts of remote Coulomb scattering (RCS) on hole mobility in ultra-thin body silicon-on-insulator (UTB SOI) p-MOSFETs at cryogenic temperatures are investigated. The physical models including phonon scattering, surface roughness scattering, and remote Coulomb scatterings are considered, and the results are verified by the experimental results at different temperatures for both bulk (from 300 K to 30 K) and UTB SOI (300 K and 25 K) p-MOSFETs. The impacts of the interfacial trap charges at both front and bottom interfaces on the hole mobility are mainly evaluated for the UTB SOI p-MOSFETs at liquid helium temperature (4.2 K). The results reveal that as the temperature decreases, the RCS due to the interfacial trap charges plays an important role in the hole mobility.</jats:p>