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<jats:p>We investigated single-electron tunneling through single and coupling dopant-induced quantum dots (QDs) in silicon junctionless nanowire transistor (JNT) by varying temperatures and bias voltages. We observed that two possible charge states of the isolated QD confined in the axis of the initial narrowest channel are successively occupied as the temperature increases above 30 K. The resonance states of the double single-electron peaks emerge below the Hubbard band, at which several subpeaks are clearly observed respectively in the double oscillated current peaks due to the coupling of the QDs in the atomic scale channel. The electric field of bias voltage between the source and the drain could remarkably enhance the tunneling possibility of the single-electron current and the coupling strength of several dopant atoms. This finding demonstrates that silicon JNTs are the promising potential candidates to realize the single dopant atom transistors operating at room temperature.</jats:p>

<jats:p>The temperature dependences of upper critical field (<jats:italic>H</jats:italic> <jats:sub>c2</jats:sub>) for a series of iron-deficient Fe<jats:sub>1−<jats:italic>x</jats:italic> </jats:sub>Se single crystals are obtained from the measurements of in-plane resistivity in magnetic fields up to 9 T and perpendicular to the <jats:italic>ab</jats:italic> plane. For the samples with lower superconducting transition temperature <jats:italic>T</jats:italic> <jats:sub>c</jats:sub> (&lt;7.2 K), the temperature dependence of <jats:italic>H</jats:italic> <jats:sub>c2</jats:sub> is appropriately described by an effective two-band model. For the samples with higher <jats:italic>T</jats:italic> <jats:sub>c</jats:sub> (≳ 7.2 K), the temperature dependence can also be fitted by a single-band Werthamer–Helfand–Hohenberg formula, besides the two-band model. Such a <jats:italic>T</jats:italic> <jats:sub>c</jats:sub>-dependent change in <jats:italic>H</jats:italic> <jats:sub>c2</jats:sub>(<jats:italic>T</jats:italic>) behavior is discussed in connection with recent related experimental results, showing an inherent link between the changes of intrinsic superconducting and normal state properties in the FeSe system.</jats:p>

<jats:p>Recently, a contact-resistance-measurement method was developed to detect the minigap, hence the Andreev bound states (ABSs), in Josephson junctions constructed on the surface of three-dimensional topological insulators (3D TIs). In this work, we further generalize that method to the circumstance with radio frequency (rf) irradiation. We find that with the increase of the rf power, the measured minigap becomes broadened and extends to higher energies in a way similar to the rf power dependence of the outer border of the Shapiro step region. We show that the corresponding data of contact resistance under rf irradiation can be well interpreted by using the resistively shunted Josephson junction (RSJ) model and the Blonder–Tinkham–Klapwijk (BTK) theory. Our findings could be useful when using the contact-resistance-measurement method to study the Majorana-related physics in topological insulator-based Josephson junctions under rf irradiation.</jats:p>

<jats:p>The [001]<jats:sub> <jats:italic>c</jats:italic> </jats:sub>-polarized (1 − <jats:italic>x</jats:italic>)Pb(Mg<jats:sub>1/3</jats:sub>Nb<jats:sub>2/3</jats:sub>)O<jats:sub>3</jats:sub>–<jats:italic>x</jats:italic>PbTiO<jats:sub>3</jats:sub> (PMN−PT) single crystals are widely used in ultrasonic detection transducers and underwater acoustic sensors. However, the relatively small coercive field (∼ 2 kV/cm) of such crystals restricts their application at high frequencies because the driving field will exceed the coercive field. The depolarization field can be considerably larger in an antiparallel direction than in a parallel direction with respect to polarization when the bipolar driving cycle starts. Thus, if the direction of the sine wave signal in the first half cycle is opposite to the polarization direction, then the depolarized domains can be repolarized in the second half of the sine cycle. However, if the direction of the sine wave signal in the first half of the cycle is along the polarization direction, then the change is negligible, and the domains switched in the second half of the sine cycle cannot be recovered. The design of electric driving method needs to allow the use of a large applied field to emit strong enough signals and produce good images. This phenomenon combined with the coercive field increases with the driving frequency, thereby making the PMN−PT single crystals usable for high-frequency applications. As such, the applied field can be considerably larger than the conventionally defined coercive field.</jats:p>

<jats:p>High-quality dielectric/Ge interface and low gate leakage current are crucial issues for high-performance nanoscaled Ge-based complementary metal–oxide–semiconductor (CMOS) device. In this paper, the interfacial and electrical properties of high-<jats:italic>k</jats:italic> HfGdON/LaTaON stacked gate dielectric Ge metal–oxide–semiconductor (MOS) capacitors with different gadolinium (Gd) contents are investigated. Experimental results show that when the controlling Gd content is a suitable value (<jats:italic>e.g.</jats:italic>, ∼ 13.16%), excellent device performances can be achieved: low interface-state density (6.93 × 10<jats:sup>11</jats:sup> cm<jats:sup>−2</jats:sup> · eV<jats:sup>−1</jats:sup>), small flatband voltage (0.25 V), good capacitance–voltage behavior, small frequency dispersion, and low gate leakage current (2.29× 10<jats:sup>−6</jats:sup> A/cm<jats:sup>2</jats:sup> at <jats:italic>V</jats:italic> <jats:sub>g</jats:sub> = <jats:italic>V</jats:italic> <jats:sub>fb</jats:sub> + 1 V). These could be attributed to the repair of oxygen vacancies, the increase of conduction band offset, and the suppression of germanate and suboxide GeO<jats:sub> <jats:italic>x</jats:italic> </jats:sub> at/near the high <jats:italic>k</jats:italic>/Ge interface by doping suitable Gd into HfON.</jats:p>

<jats:p>An investigation of germanium-tin (GeSn) on silicon p–i–n photodetectors with a high-quality Ge<jats:sub>0.94</jats:sub>Sn<jats:sub>0.06</jats:sub> absorbing layer is reported. The GeSn photodetector reached a responsivity as high as 0.45 A/W at the wavelength of 1550 nm and 0.12 A/W at the wavelength of 2 μm. A cycle annealing technology was applied to improve the quality of the epitaxial layer during the growth process by molecular beam epitaxy. A low dark-current density under 1 V reverse bias about 0.078 A/cm<jats:sup>2</jats:sup> was achieved at room temperature. Furthermore, the GeSn photodetector could detect a wide spectrum region and the cutoff wavelength reached to about 2.3 μm. This work has great importance in silicon-based short-wave infrared detection.</jats:p>

<jats:p>Bi<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub>Se thin film could be one of the promising material candidates for the next-generation electronic and optoelectronic applications. However, the performance of Bi<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub>Se thin film-based device is not fully explored in the photodetecting area. Considering the fact that the electrical properties such as carrier mobility, work function, and energy band structure of Bi<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub>Se are thickness-dependent, the in-plane Bi<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub>Se homojunctions consisting of layers with different thicknesses are successfully synthesized by the chemical vapor deposition (CVD) method across the terraces on the mica substrates, where terraces are created in the mica surface layer peeling off process. In this way, effective internal electrical fields are built up along the Bi<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub>Se homojunctions, exhibiting diode-like rectification behavior with an on/off ratio of 10<jats:sup>2</jats:sup>, what is more, thus obtained photodetectors possess highly sensitive and ultrafast features, with a maximum photoresponsivity of 2.5 A/W and a lifetime of 4.8 μs. Comparing with the Bi<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub>Se uniform thin films, the photo-electric conversion efficiency is greatly improved for the in-plane homojunctions.</jats:p>

<jats:p>Effects of refractory period on the dynamical range in excitable networks are studied by computer simulations and theoretical analysis. The first effect is that the maximum or peak of the dynamical range appears when the largest eigenvalue of adjacent matrix is larger than one. We present a modification of the theory of the critical point by considering the correlation between excited nodes and their neighbors, which is brought by the refractory period. Our analysis provides the interpretation for the shift of the peak of the dynamical range. The effect is negligible when the average degree of the network is large. The second effect is that the dynamical range increases as the length of refractory period increases, and it is independent of the average degree. We present the mechanism of the second effect. As the refractory period increases, the saturated response decreases. This makes the bottom boundary of the dynamical range smaller and the dynamical range extend.</jats:p>

<jats:p>Alkaline phosphatase (ALP) plays an integral role in the metabolism of liver and development of the skeleton in humans. To date, the interactions between different-duration terahertz (THz) radiation and ALP activities, as well as the influence mechanism are still unclear. In this study, using the para-nitro-phenyl-phosphate (pNPP) method, we detect changes in ALP activities during 40-minute THz radiation (0.1 THz, 13 mW/cm<jats:sup>2</jats:sup>). It is found that the activity of ALP decreases in the first 25 min, and subsequently increases in the later 15 min. Compared with the activity of ALP being heated, the results suggest that short-term terahertz radiation induces a decrease in enzyme activity through the non-thermal mechanism. In order to explore the non-thermal effects of THz radiation on ALP, we focus on the impacts of 0.1 THz radiation for 20 min on the activity of ALP in different concentrations. The results reveal that the activity of ALP decreases significantly after exposure to THz radiation. In addition, it could be deduced from fluorescence, ultraviolet-visible (UV-vis), and THz spectra results that THz radiation has induced changes in ALP structures. Our study unlocks non-thermal interactions between THz radiation and ALP, as well as suggests that THz spectroscopy is a promising technique to distinguish ALP structures.</jats:p>

<jats:p>Particle tracking velocimetry (PTV) is one of the most commonly applied granular flow velocity measurement methods. However, traditional PTV methods may have issues such as high mismatching rates and a narrow measurement range when measuring granular flows with large bulk density and high-speed contrast. In this study, a novel PTV method is introduced to solve these problems using an optical flow matching algorithm with two further processing steps. The first step involves displacement correction, which is used to solve the mismatching problem in the case of high stacking density. The other step is trajectory splicing, which is used to solve the problem of a measurement range reduction in the case of high-speed contrast The hopper flow experimental results demonstrate superior performance of this proposed method in controlling the number of mismatched particles and better measuring efficiency in comparison with the traditional PTV method.</jats:p>