查看更多>>摘要：A label-free platform based on integration of cantilever and photonic crystal cavity resonator is reported with both high sensitivity and ultra-high quality factor for femto-gram detection of chemicals. The proposed chemical sensor shows sharp resonant frequency with quality factor of 12800, displacement and wavelength shift is obtained as 29.9425 μm and 7.15625 nm with chemical weight of 100 fg. The proposed sensor shows a high confinement factor of 62%, with an average sensitivity of 1.62 nm/fg manifested its promising applications for detection of various virus present in chemicals. The device shows capability to work in various fluids for chemical sensing purposes.
查看更多>>摘要：This theoretical study investigates strategies for minimizing Joule losses in resistive random access memory (ReRAM) cells, which are also referred to as memristive devices. Typically, the structure of ReRAM cells involves a nanoscale layer of resistance-switching material sandwiched between two metal electrodes. The basic question that we ask is what is the optimal driving protocol to switch a memristive device from one state to another. In the case of ideal memristors, in the most basic scenario, the optimal protocol is determined by solving a variational problem without constraints with the help of the Euler-Lagrange equation. In the case of memristive systems, for the same situation, the optimal protocol is found using the method of Lagrange multipliers. We demonstrate the advantages of our approaches through specific examples and compare our results with those of switching with constant voltage or current. Our findings suggest that voltage or current control can be used to reduce Joule losses in emerging memory devices.
查看更多>>摘要：In this article, a cost-effective technique for the synthesis of gamma iron oxide nanoparticles has been proposed for intelligent maghemite electrode applications pitched in the context of smart and efficient energy storage solution. A facile process-optimized technique for synthesis of gamma iron oxide nanoparticles has been designed in order to investigate the optimum temperature, doping and pH of the sodium hydroxide. By dint of morphological investigation, it has been established that the samples have high surface area, crystalline structure, and size in the range of fifty to hundred angstrom. The linearity of the magnetization feature coupled with its doping sensitivity points towards its usage for state estimation technology of the energy storage device management. The nano-scaled samples witness an increase of 75%–110% in the direct bandgap in comparison to its bulk existence. This band gap modulation establishes that the conductivity can be improved for electrode application by doping. High surface area for the active material ingredient nano-particles has also been confirmed by BET surface area of up to 75 m2/g. Thermal analyses of the samples establish the fidelity of the samples’ constitution over a desirably wide temperature range. The cost-effectiveness of gamma-iron oxide batteries will be a crucial factor for faster adoption of indigenous renewable energy storage solutions.
Sanjana Devi VSBalraj BAmuthameena SJoby Titus T...
27-33页
查看更多>>摘要：This study investigates the enhancement of hydrogen (H2) gas sensing in nitrogen-doped Zinc Oxide (ZnO) nanomaterials through the decoration of gold (Au) nanoparticles. ZnO nanoparticles were synthesized via a wet chemical method, doped with nitrogen at 0.5%, 1.0%, and 1.5% concentrations, and decorated with Au nanoparticles. Characterization using X-ray diffraction (XRD) revealed that the ZnO structure remained intact, with the addition of a peak corresponding to Au at 38.19°. Transmission electron microscopy (TEM) confirmed the uniform distribution of spherical Au nanoparticles on the ZnO surfaces. UV-Vis spectroscopy showed an enhanced absorption peak at 532 nm due to surface plasmon resonance. Photoluminescence (PL) spectra indicated reduced emission intensity, suggesting effective charge transfer between ZnO and Au. Gas sensing tests revealed that Au-decorated 1.0 wt. % N exhibited a maximum H2 gas response of 89% at 200 °C, significantly higher than the 46% response of non-decorated 1.0 wt. % N. Additionally, the Au-decorated N sensors demonstrated a rapid response time of 10 sec and a recovery time of 15 sec. These results highlight the potential of Au-decorated N-doped nanomaterials as highly efficient H2 gas sensors, combining enhanced sensitivity with fast response kinetics.
查看更多>>摘要：This article presents an electronically tunable metasurface wideband absorber with a graphene-based unit cell designed for the lower terahertz (0.1 THz– 10 THz) region. Surface plasmonics and the controllable conductance of graphene make it ideal for this purpose. Dual wideband absorption ($ $90% absorptivity) was observed from 0.682 to 1.798 THz (90% fractional bandwidth) and 4.187 to 4.947 THz (16% fractional bandwidth). The absorber is insensitive to polarizations and oblique incidences up to 45°. The unit cell comprises a double elliptical-cross graphene monolayer on a polyimide substrate (dielectric constant: 3.5, loss tangent: 0.0024) backed by an ultra-thin gold layer. Plasmonic resonance, introduced by four semicircular slots, causes absorption from 4.15 to 4.95 THz. Absorption properties were verified through a transmission line model and finite element method (FEM) simulations. Tunability is investigated via gating potential, carrier relaxation time, and Fermi energy variations.
查看更多>>摘要：This study tested fluorine doping on various regions of the ferroelectric charge trap gate stack (FEG stack). Fluorine doping effectively reduces oxygen vacancies in the dielectric layer, thus reducing leakage current and stabilizing charge in the dielectric layer. Moreover, fluorine doping can passivate the dangling bonds at the interface and increase the ability of trapping carriers in the trap layer. The FEG stack comprises a tunnel oxide layer (TL), a charge trap layer (CTL), and a ferroelectric layer (FE). Four types of devices were fabricated: undoped, doping in TL, doping in CTL, and doping in both TL and CTL, to investigate the impact of fluorine doping on the FEG gate stack. Devices doping in TL and CTL demonstrated superior performance, achieving the highest Vth of 5.4 V with a retention time of 70.42% after 10, 000 seconds. The off-state and gate leakage tests revealed impressive breakdown voltages of 735 V and 24.55 V, respectively. Furthermore, the device exhibited a high operation voltage of 14.3 V for a 10-year lifetime prediction, enabling a wide operating range.
查看更多>>摘要：The power and energy densities of a Supercapacitor (SC) is largely dictated by the accessibility of the nano-porous area of the electrode to the electrolyte ions. Carbon nanotubes (CNT) have high electrical conductivity, and more importantly, may be grown into architectures with high surface area. However, this is not easy to achieve in practice. CNT electrodes are fabricated by chemical vapor deposition (CVD), after a metal catalyst layer is coated on a current collector. In this work, the control of the metal catalyst layer, by varying the dip-coating time and CVD process parameters, is shown to be crucial to pore morphology and consequent SC performance. The dip-coating time is adjusted to obtain thin and uniform coating. Further, optimum reduction of the nickel layer with hydrogen is required to produce thin CNTs with adequate inter-tube separation that facilitate ion accessibility within the pores. The height of the CNT forest is also optimized to prevent decrease in specific capacitance due to reduced accessibility. Proper optimization of the process parameters results in a pore morphology conductive to ion diffusion, and simultaneous improvement in energy and power density.
查看更多>>摘要：Recently, deuterium annealing at a reduced temperature range of 300 °C has been proposed to enhance SiO2 gate dielectrics and the Si/SiO2 interface, thereby improving device reliability. As a further investigation into deuterium annealing, for the first time this study compared deuterium absorption characteristics with various SiO2 dielectrics formed by wet oxidation, dry oxidation, low-pressure chemical vapor deposition (LPCVD), and plasma-enhanced chemical vapor deposition (PECVD). Deuterium annealing can also be used to reduce the roughness and improve the uniformity of SiO2 dielectric films. Surface roughness of various samples was measured and quantitatively compared using atomic force microscopy (AFM) after deuterium annealing.
查看更多>>摘要：In this paper, a novel tunneling-drift-diffusion field-effect transistor (TDDFET) is introduced with dual-doped source and asymmetric gates. In the TDDFET, the current is conducted by two mechanisms, namely the band-to-band tunneling and drift-diffusion, making the device can present an additional state between the on and off states, and very suitable for the ternary logic design. Additionally, a standard ternary inverter (STI) is also implemented based on the TDDFET and studied in detail by the aid of TCAD simulation. It turns out that the supply voltage VDD shows significant influence on the ternary inverter and the optimized value is about 3Vturn/2 in which Vturn is the transition voltage on the transfer curve. The influence of key device parameters are also studied in detail. Compared with other ternary inverters, our designed ternary inverter requiring no any immature material, passive device and multi-valued power supply, is more friendly with the CMOS platform and can make the most of the advantages of the ternary logic.
查看更多>>摘要：Non-homogeneous orthorhombic phase in doped ferroelectric (FE) HfO$_{2}$ film presents challenges towards the optimization and performance predictability of negative capacitance (NC) field-effect transistor (FET) performance. We set out to understand the consequences of these dielectric (DE) phases in doped FE-HfO$_{2}$ on steep-switching device performance through self-consistent quantum transport simulations. Firstly, we consider a fixed DE phase study to understand how the position, percentage, and number of phase components alter the switching characteristics. Then, to predict device performance variation, we conduct a statistical analysis using a large number of randomly distributed DE phase profiles. We find that DE phases positioned near the center of the potential barrier exert the most significant impact on device performance by lowering the top-of-the-barrier, while those closer to the drain have minimal influence on carrier transport and current. While DE phases in the FE layer degrade the subthreshold swing, they also favorably narrow the hysteretic window, which presents opportunities for optimization in logic devices. Through dimensional scaling and statistical analysis, we demonstrate how optimized performance can be achieved even with large variations in device performance.
NETL
NSTL
IEEE