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<jats:p>The linkage structures between monomers make great influence on the properties of polymers. The synthesis of some special linkage structures can be challenging, which is often overcome by employing special reaction conditions. Here,we build dihydropentalene linkage in poly-naphthalocyanine on Ag(110) surface. Scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM) measurements confirm the dihydropentalenelinkage structure and a possible formation path with reconstruction steps is proposed. The controlled experiment on Ag(100) surface shows no dihydropentalene structures formed, which indicates the grooved substrate is necessary for the reconstruction. This work provides insights into the surface restricted reactions that can yield special structures in organic polymers.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Recently, the memory elements-based circuits have been addressed frequently in the nonlinear circuit theory due to their unique behaviors. Thus, the modeling and characterizing of the mem-elements become essential. In this paper, the analysis of the multiple fractional-order voltage-controlled memcapacitors model in parallel connection is studied. Firstly, two fractional-order memcapacitors are connected in parallel, the equivalent model is derived, and the characteristic of the equivalent memcapacitor is analyzed in positive or negative connection. Then a new understanding manner according to different rate factor <jats:italic>K</jats:italic> and fractional order <jats:italic>α</jats:italic> is derived to explain the equivalent modeling structure conveniently. Additionally, the negative order appears, which is a consequence of the combination of memcapacitors in different directions. Meanwhile, the equivalent parallel memcapacitance has been drawn to determine that multiple fractional-order memcapacitors could be calculated as one composite memcapacitor. Thus, an arbitrary fractional-order equivalent memcapacitor could be constructed by multiple fractional-order memcapacitors.</jats:p>

<jats:p>The energy deposition and electrothermal behavior of SiC metal–oxide–semiconductor field-effect transistor (MOSFET) under heavy ion radiation are investigated based on Monte Carlo method and TCAD numerical simulation. The Monte Carlo simulation results show that the density of heavy ion-induced energy deposition is the largest in the center of the heavy ion track. The time for energy deposition in SiC is on the order of picoseconds. The TCAD is used to simulate the single event burnout (SEB) sensitivity of SiC MOSFET at four representative incident positions and four incident depths. When heavy ions strike vertically from SiC MOSFET source electrode, the SiC MOSFET has the shortest SEB time and the lowest SEB voltage with respect to direct strike from the epitaxial layer, strike from the channel, and strike from the body diode region. High current and strong electric field simultaneously appear in the local area of SiC MOSFET, resulting in excessive power dissipation, further leading to excessive high lattice temperature. The gate–source junction area and the substrate–epitaxial layer junction area are both the regions where the SiC lattice temperature first reaches the SEB critical temperature. In the SEB simulation of SiC MOSFET at different incident depths, when the incident depth does not exceed the device’s epitaxial layer, the heavy-ion-induced charge deposition is not enough to make lattice temperature reach the SEB critical temperature.</jats:p>

<jats:p>Heterogeneous integrated InP high electron mobility transistors <jats:bold>(HEMTs)</jats:bold> on quartz wafers are fabricated successfully by using a reverse-grown InP epitaxial structure and benzocyclobutene <jats:bold>(BCB)</jats:bold> bonding technology. The channel of the new device is In<jats:sub>0.7</jats:sub>Ga<jats:sub>0.3</jats:sub>As, and the gate length is 100 nm. A maximum extrinsic transconductance <jats:italic>g</jats:italic> <jats:sub>m,max</jats:sub> of 855.5 mS/mm and a maximum drain current of 536.5 mA/mm are obtained. The current gain cutoff frequency is as high as 262 GHz and the maximum oscillation frequency reaches 288 GHz. In addition, a small signal equivalent circuit model of heterogeneous integration of <jats:bold>InP HEMTs</jats:bold> on quartz wafer is built to characterize device performance.</jats:p>

<jats:p>Voltage-controlled magnetic skyrmions have attracted special attention because they satisfy the requirements for well-controlled high-efficiency and energy saving for future skyrmion-based neuron device applications. In this work, we propose a compact leaky-integrate-fire (LIF) spiking neuron device by using the voltage-driven skyrmion dynamics in a multiferroic nanodisk structure. The skyrmion dynamics is controlled by well tailoring voltage-induced piezostrains, where the skyrmion radius can be effectively modulated by applying the piezostrain pulses. Like the biological neuron, the proposed skyrmionic neuron will accumulate a membrane potential as skyrmion radius is varied by inputting the continuous piezostrain spikes, and the skyrmion radius will return to the initial state in the absence of piezostrain. Therefore, this skyrmion radius-based membrane potential will reach a definite threshold value by the strain stimuli and then reset by removing the stimuli. Such the LIF neuronal functionality and the behaviors of the proposed skyrmionic neuron device are elucidated through the micromagnetic simulation studies. Our results may benefit the utilization of skyrmionic neuron for constructing the future energy-efficient and voltage-tunable spiking neural networks.</jats:p>

<jats:p>A three-dimensional (3D) silicon-carbide (SiC) trench metal–oxide–semiconductor field-effect transistor (MOSFET) with a heterojunction diode (HJD-TMOS) is proposed and studied in this work. The SiC MOSFET is characterized by an HJD which is partially embedded on one side of the gate. When the device is in the turn-on state, the body parasitic diode can be effectively controlled by the embedded HJD, the switching loss thus decreases for the device. Moreover, a highly-doped P<jats:sup>+</jats:sup> layer is encircled the gate oxide on the same side as the HJD and under the gate oxide, which is used to lighten the electric field concentration and improve the reliability of gate oxide layer. Physical mechanism for the HJD-TMOS is analyzed. Comparing with the conventional device with the same level of on-resistance, the breakdown voltage of the HJD-TMOS is improved by 23.4%, and the miller charge and the switching loss decrease by 43.2% and 48.6%, respectively.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We fabricated a set of symmetric gate-recess devices with gate length of 70 nm. We kept the source-to-drain spacing (<jats:italic>L</jats:italic> <jats:sub>SD</jats:sub>) unchanged, and obtained a group of devices with gate-recess length (<jats:italic>L</jats:italic> <jats:sub>recess</jats:sub>) from 0.4 μm to 0.8 μm through process improvement. In order to suppress the influence of the kink effect, we have done SiN<jats:sub> <jats:italic>X</jats:italic> </jats:sub> passivation treatment. The maximum saturation current density (<jats:italic>I</jats:italic> <jats:sub>D_max</jats:sub>) and maximum transconductance (<jats:italic>g</jats:italic> <jats:sub>m,max</jats:sub>) increase as <jats:italic>L</jats:italic> <jats:sub>recess</jats:sub> decreases to 0.4 μm. At this time, the device shows <jats:italic>I</jats:italic> <jats:sub>D_max</jats:sub>=749.6 mA/mm at <jats:italic>V</jats:italic> <jats:sub>GS</jats:sub>=0.2 V, <jats:italic>V</jats:italic> <jats:sub>DS</jats:sub>=1.5 V, and <jats:italic>g</jats:italic> <jats:sub>m_max</jats:sub>=1111 mS/mm at <jats:italic>V</jats:italic> <jats:sub>GS</jats:sub>=−0.35 V, <jats:italic>V</jats:italic> <jats:sub>DS</jats:sub>=1.5 V. Meanwhile, as <jats:italic>L</jats:italic> <jats:sub>recess</jats:sub> increases, it causes parasitic capacitance <jats:italic>C</jats:italic> <jats:sub>gd</jats:sub> and <jats:italic>g</jats:italic> <jats:sub>d</jats:sub> to decrease, making <jats:italic>f</jats:italic> <jats:sub>max</jats:sub> drastically increases. When <jats:italic>L</jats:italic> <jats:sub>recess</jats:sub> = 0.8 μm, the device shows <jats:italic>f</jats:italic> <jats:sub>T</jats:sub>=188 GHz and <jats:italic>f</jats:italic> <jats:sub>max</jats:sub>=1112 GHz.</jats:p>

<jats:p>To enhance device performance and reduce fabrication cost, a series of electron transporting material (ETM)-free perovskite solar cells (PSCs) is developed by TCAD Atlas. The accuracy of the physical mode of PSCs is verified, due to the simulations of PEDOT:PSS–CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>PbI<jats:sub>3</jats:sub>–PCBM and CuSCN–CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>PbI<jats:sub>3</jats:sub>–PCBM p–i–n PSCs showing a good agreement with experimental results. Different hole transporting materials (HTMs) are selected and directly combined with n-CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>PbI<jats:sub>3</jats:sub>, and the CuSCN–CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>PbI<jats:sub>3</jats:sub> is the best in these ETM-free PSCs. To further study the CuSCN–CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>PbI<jats:sub>3</jats:sub> PSC, the influences of back electrode material, gradient band gap, thickness, doping concentration, and bulk defect density on the performance are investigated. Energy band and distribution of electric field are utilized to optimize the design. As a result, the efficiency of CuSCN–CH<jats:sub>3</jats:sub>NH<jats:sub>3</jats:sub>PbI<jats:sub>3</jats:sub> PSC is achieved to be 26.64%. This study provides the guideline for designing and improving the performances of ETM-free PSCs.</jats:p>

<jats:p>Stock markets in the world are linked by complicated and dynamical relationships into a temporal network. Extensive works have provided us with rich findings from the topological properties and their evolutionary trajectories, but the underlying dynamical mechanism is still not in order. In the present work, we proposed a technical scheme to reveal the dynamical law from the temporal network. The index records for the global stock markets form a multivariate time series. One separates the series into segments and calculates the information flows between the markets, resulting in a temporal market network representing the state and its evolution. Then the technique of the Koopman decomposition operator is adopted to find the law stored in the information flows. The results show that the stock market system has a high flexibility, <jats:italic>i.e.</jats:italic>, it jumps easily between different states. The information flows mainly from high to low volatility stock markets. And the dynamical process of information flow is composed of many dynamic modes distribute homogenously in a wide range of periods from one month to several ten years, but there exist only nine modes dominating the macroscopic patterns.</jats:p>

<jats:p>Rank-1 attractors play a vital role in biological systems and the circuit systems. In this paper, we consider a periodically kicked Chua model with two delays in a circuit system. We first analyze the local stability of the equilibria of the Chua system and obtain the existence conditions of supercritical Hopf bifurcations. Then, we derive some explicit formulas about Hopf bifurcation, which could help us find the form of Hopf bifurcation and the stability of bifurcating period solutions through the Hassards method. Also, we show that rank-1 chaos occurs when the Chua model with two delays undergoes a supercritical Hopf bifurcation and encounters a periodic kick, which shows the effect of two delays on the circuit system. Finally, we illustrate the theoretical analysis by simulations and try to explain the mechanism of delay in our system.</jats:p>