Owing to the outstanding physical properties of graphene, its biosensing applications implemented by the terahertz metasurface are widely concerned and studied. Here, we present a novel design of the graphene metasurface, which consists of an individual graphene ring and an H-shaped graphene structure. The graphene metasurface exhibits a dual-resonance response, whose resonance frequency strongly varies with the geometrical parameters of the proposed metasurface, the carrier density of graphene, and the analyte composition. The transparency window, including width and position, can be artificially controlled by adjusting the geometrical parameters or the Fermi energy. Furthermore, the sensing parameters of the graphene metasurface for cancerous and normal cells are investigated, focusing on two factors, namely cell quantity and position on the metasurface. The simulated results clearly show that the theoretical sensitivity, figure of merit, and quantity of the graphene metasurface for breast cells reach 1.21 THz/RIU, 2.75 RIU${}^{-1}$, and 2.43, respectively. Our findings may open up new avenues for promising applications in the diagnosis of cancers.

Using TCAD simulations, the silicon carbide metal-oxide-semiconductor field-effect transistor with p-type floating islands (SiC FLIMOSFET) is systematically investigated in this paper. The doping concentration (NFLI), length (L), and position (D1) of floating islands are optimized according to breakdown voltage (BV), electric field distribution, and on-resistance. The results show that NFLI = 1 x 10¹⁷ cm⁻³, L= 2.5 μm, and D1=9.0 μm are superior values for FLI structure considering tradeoff between BV and on-resistance. With the same BV capacity, the on-resistance of SiC FLIMOSFET is decrease by 32% comparing to the conventional SiC VDMOSFET. Besides, the dynamic property shows 16.5% reduction of FoM Ron· QGD in the SiC FLIMOSFET. Significantly, comparing to the conventional structure, the electro-thermal simulation indicates that the SiC FLIMOSFET has a higher robustness under short-circuit condition owing to the reduction of thermal stress in SiC/SiO₂ interface. All the results show that the SiC FLIMOSFET has a good potential in SiC power device.

Recent reports focus on the hydrogenation engineering of monolayer boron phosphide and simultaneously explore its promising applications in nanoelectronics. Coupling density functional theory and finite element method, we investigate the bowtie triangle ring microstructure composed of boron phosphide with hydrogenation based on structural and performance analysis. We determine the carrier mobility of hydrogenated boron phosphide, reveal the effect of structural and material parameters on resonance frequencies, and discuss the variation of the electric field at the two tips. The results suggest that the mobilities of electrons for hydrogenated BP monolayer in the armchair and zigzag directions are 0.51 and 94.4 cm²·V${}^{-1}$·s${}^{-1}$, whereas for holes, the values are 136.8 and 175.15 cm²·V${}^{-1}$·s${}^{-1}$. Meanwhile, the transmission spectra of the bowtie triangle ring microstructure can be controlled by adjusting the length of the bowtie triangle ring microstructure and carrier density of hydrogenated BP. With the increasing length, the transmission spectrum has a red-shift and the electric field at the tips of equilateral triangle rings is significantly weakened. Furthermore, the theoretical sensitivity of the BTR structure reaches 100 GHz/RIU, which is sufficient to determine healthy and COVID-19-infected individuals. Our findings may open up new avenues for promising applications in the rapid diagnosis of COVID-19.

Exploring effective disinfection methods and understanding their mechanisms on the new coronavirus is becoming more active due to the outbreak of novel coronavirus pneumonia (COVID-19) caused by severe acute respiratory coronavirus 2 (SARS-CoV-2).

The wide-bandgap semiconductors represented by GaN have a broad application prospect because of their high service temperature and high switch frequency. Quad-Flat-No-Lead (QFN) Package is currently one of the mainstream packaging methods due to its low cost and high efficiency. However, the low reliability of QFN used in GaN devices is still a crucial problem caused by elevated temperatures and the thermal stress induced by the mismatch of coefficient of thermal expansion (CTE). Therefore, it is necessary to control the temperature inner the package and increase the mechanical property of the bonding layer. In this paper, the finite element method (FEM) with thermal-mechanical coupling is performed to optimize the reliability of the bonding layer by adopting sinter nano Cu and silver. Based on the conventional QFN package module, we tried to add different metallization on the bonding surface to decrease the influence of CTE mismatch. We should note that the Anand viscoplastic model was used in the materials of Sintered Ag and lead-free solder paste presented by SAC305, which were the most commonly used in die-attachment. The results showed that the utilization of nano copper/silver paste could hardly facilitate thermal performance although sintered Ag had excellent thermal conductivity. Since the Anand modules of Ag and SAC305 were different, there were some impacts on the stress distribution and deformation. During the bonding process, a large thermal stress generated between die-attachment layer and Package or the PCB. The die-attachment layer formed by nano Ag paste suffered the smaller thermal stress because its CTE is comparable to that of thermal pad. In terms of sintered Ag, the bonding layer generated more elastic strain. As the deformation recovered to initial stage, the stress decreased because of the elastic strain. And we also found that the Ag metallization could decreased the maximum stress of model at heating stage. But Ag metallization suffered larger thermal stress as the temperature decreased. The selection of connection materials and metallization are a crucial part of design the structure of electronic package. And this paper could provide a reference for optimize the package structure to further improve their reliability in future works.

Silicon carbide (SiC) is presenting as an attractive material for the next generation high voltage power devices which benefits from its excellent material properties. SiC Schottky barrier diode (SBD) compares with silicon based, which has superior characteristics in terms of rectification, reverse recovery time, etc. In this paper, a high voltage 4H-SiC SBD with reverse breakdown voltage of 1800 V and forward current of 40 A is designed as implemented in TCAD. The termination structure of the device is designed with multiple Field Limiting Rings (FLRs). The parameters of the active area and FLRs terminal protection structure are optimized. The steady state and transient characteristics of the device are simulated separately. As a result, the thickness of the N-type epitaxial layer is 16 μm and the doping concentration is 5.8×10 ¹⁵ cm ^-3 . Furthermore, the forward current is 40 A when the forward voltage is 1.60 V at room temperature. Finally, a temperature generation model is added to calculate the lattice temperature profile and analysis areas of possible failure during pulsed operation.