All-photonic response in Silicon (Si) nanoparticles is dominated by magnetic resonance, leading to enhance light concentration for energy harvesting and magnetic imaging applications. The resonance phenomena occur when the natural frequency of the system matches external excitation and is well-explained by linear circuit analysis. In this paper, we propose a spherical wave impedance approach by employing the basic concept of impedance known at microwave frequencies, where it is defined as the ratio of the electric and magnetic fields to derive necessary magnetic resonance conditions. The model is used to derive various cross-section efficiencies, with results showing close agreement with the Mie solution. The proposed model is simple and compact and defines the resonance phenomena in Si nanoparticles using lumped circuit components, which is necessary for the large-scale all-photonic application of magnetic resonance using dielectric nanoparticles.

In the processor-memory separated von-Neumann computation paradigm, the “memory-wall” effect becomes critical due to large access latency and tremendous amount of data movement. In this work, we pursue cryogenic temperature based memory design and focus on spin-transfer-torque magnetoresistive random access memory (STT-MRAM) at 77-Kelvin (achieved with low-cost liquid nitrogen). Cryogenic compact model and its related cryogenic bit-cell are investigated, based on 77 K experiment data of magnetic tunnel junction (MTJ) and CMOS transistor. Compared with the simulated room temperature results, 70% reduction of sensing latency can be obtained at 0.7 V supply voltage, whereas writing latency and yield performance are significantly degraded. In order to overcome the above drawbacks, a novel joint trimming system is proposed including a build-in-self-test (BIST) block and a string of multi-stage level shifters (LS). A case study is executed with in-MRAM computing (IMC). Results show that cryogenic IMC with write trimming provides performance improvements of 33% on average, and concurrently reduces memory energy consumption by 70% on average. The proposed 77 K cryogenic design method can be further applied to other energy constrained applications.

This paper reports the complementary resistive switching (CRS) characteristics exhibited by Au/ZnO/Al 2 O 3 / Fluorine doped tin oxide (FTO) bilayer device for the first time, where both ZnO and Al 2 O 3 are active switching layers exhibiting resistive switching properties. The I-V characteristics of the device initially show bipolar resistive switching (BRS) for a few cycles (∼12) before permanently switching to CRS with the extension of SET voltage. The stable CRS state of the device exhibits a high current of ∼500 μA during the ON-state and low current of 3 × 10 −7 A during OFF-state at low input voltages (−0.5 V to 0.5 V) enables the proposed device suitable to use in crossbar array to mitigate the sneak path current. The device performance to write and read processes is evaluated with pulses of magnitudes ∼|2.5| V and 1.3 V, respectively, and showed a ∼60 μA difference in read-out current between data bits 0 and 1. Similarly, the device's power consumption is also measured to elucidate that the device is suitable to use as a memory unit with power consumption in the order of microwatts (μW). Further, the possible switching mechanism is demonstrated based on oxygen vacancies migration.

Benefitted from the strong compatibility and scalability, Hf 0.5 Zr 0.5 O 2 (HZO) based ferroelectric field-effect transistor (FeFET) has gained extensive attention as artificial neuron and synapse. In this work, with in-depth understanding of the correlations between domain switching (DS) and charge trapping (CT), multi-states in FeFET are controlled precisely by modulating the channel conductance. When DS contribution dominates, cycle-to-cycle variations can be well suppressed in the intermediate storage states. With further co-optimizations by including CT and temperature impacts, symmetric linear conductance modulations and large conductance ratios are achieved simultaneously. The biological synaptic potentiation and depression characteristics demonstrate the great potential of HZO FeFET in neuromorphic computing.

The effects of Argon (Ar) on the Synthesis and Photocatalytic activities of monolayer Graphene under the flow of Methane (CH4) and Hydrogen (H2) gas has been studied. The Chemical Vapor Deposition (CVD) method was used to create a large area of monolayer graphene with features that meet the needs of a wide variety of applications. With this, the possibility of varying the dimensions of graphene by differing the argon gas while keeping other parameters constant was demonstrated. This helps with the ability to control the size and number of layers of graphene for different applications. Further, the photocatalytic activities of produced graphene were examined during CVD at various argon gas flow rates to observe their effects on the performances of graphene. The result shows that the synthesized graphene at Ar = 80 sccm is a monolayer with perfectly shaped edges. After exfoliation, the graphene obtained was properly formed with a large surface area, which helped achieve the results of higher photocatalytic activity.

Reconfigurable Field Effect Transistors can be electrostatically programmed to p- or n-type behavior. This device level reconfigurability is a promising way to enhance the functionality of digital circuits. Here, we present a Verilog-A based Germanium nanowire table model for the analysis of dynamically reconfigurable logic gates. The model is based on TCAD simulations of a nanowire transistor design with feature sizes compatible to a 14nm FinFET process. To showcase that our model enables digital circuit design for reconfigurable operation, performance and power consumption estimations for basic static as well as reconfigurable logic cells are given. Performance improvements over Silicon nanowire based designs are predicted, making Germanium RFETs a promising candidate for future co-integration into standard CMOS processes.

Metasurface absorber-based terahertz biosensors are one of the emerging fields for sensing devices because of their quick response to changes in the background refractive index, small size, easier fabrication and measurement. In this article, a simple design and highly sensitive metasurface absorber is presented for the detection of the change in background refractive index. The proposed device provides maximum sensitivity of 2.37 THz/RIU, Q-factor of 574.46, and FOM of 540 RIU −1 for the refractive index ranges from 1.0 to 1.37. The meta-atom consists of a bow-tie metallic patch that exhibits dual-band absorptance at 1.93 THz and 2.7 THz for the x-polarized incident wave. The surface resonances at 2.7 THz result in narrow bandwidth with a very high Q-factor which enable the sensing ability of the proposed device. The sensing performance of the proposed metasurface is demonstrated by detecting the tuberculosis bacteria in the blood sample. The extremely good traits of the proposed metasurface absorber-based sensor can be utilized to detect other viruses and bacteria present in the blood cells for diagnosis applications.

This paper presents hybrid design of a Ternary Inverter (TI) circuit by integrating an Ovonic-Threshold-Switching (OTS) based Phase-Change-Memory (PCM) cell between Complementary-Metal-Oxide-Semiconductor (CMOS) transistors. Volatile OTS behaviour of the PCM structure helps to generate the ternary state. Reliability of the proposed TI design has been demonstrated through the Monte-Carlo simulations in Cadence-Spectre simulator incorporating both Process and Mismatch variability at all corners. The proposed inverter cell consumes 10.44 $\mu$ W power and 1.47 ns delay on UMC-180 nm technology node. Moreover to demonstrate the scaling potential, we have simulated the proposed inverter at various technology nodes i.e 180/90/65/28 nm. At advanced feature sizes, power and delay are improved by significant amount. For benchmarking, we have compared the proposed TI design with various state-of-the-art hybrid structures. Furthermore, to demonstrate potential applications, we designed and simulated ternary universal logic gates i.e NAND/NOR. Benefits of the proposed TI in circuit applications are shown through a Ternary Multiplier (TMUL) arithmetic circuit implementation. Finally, a Ternary-Static-Random-Access-Memory (TSRAM) is proposed with two back-to-back connected CMOS-PCM TIs with three bit storing capability.

We improve photovoltaic performance by incorporating graphene quantum dots (GQDs) into dye-sensitized solar cells (DSSCs). GQD can emit green fluorescence (∼530 nm) in the ultraviolet wavelength range (∼340 nm), and this characteristic is applied to enhance the light absorption ability of N719 dye. Using GQDs as auxiliary sensitizers to achieve co-sensitization with N719 dye can enhance the photovoltaic performance of DSSCs. We observed the photoresponse characteristics of DSSCs with different sensitization effects by incident photon-to-current conversion efficiency (IPCE). According to the results, the photoelectric conversion efficiency of DSSCs using the GQD+N719 co-sensitized photoanode was increased to 5.14%, which is a 20% improvement.

In this article, negative capacitance effect on metal-ferro-metal-insulator-semiconductor (MFMIS) type FDSOI negative-capacitance-FET (NCFET) has been investigated by considering two well known thin-film ferro-dielectric ( $ Fe$ ) materials HZO (zirconium:HfO $_{2}$ ) and HSO (silicon:HfO $_{2}$ ). The investigations are carried out in a well calibrated TCAD environment, where the gate-charge ( $ Q_{G}$ ) is extracted from the TCAD simulation. And, subsequently computing the ferro-voltage ( $ V_{Fe}$ ) across $ Fe$ -capacitor to estimate the total effective gate voltage ( $ V_{GS}$ ) on the gate-stack of FDSOI NCFET. The depicted values are subjected to increment in $ Fe$ -thickness ( $ t_{Fe}$ ) to optimize HZO and HSO $ Fe$ -materials for FDSOI NCFET(s). The optimised NCFET(s) are later levied with back-gate bias (V $_{\mathrm{B}}$ ) variation with the motivation of utilizing the attributes of FDSOI MOSFETs of V $_{\text{TH}}$ shift can further enhance the device performance. Depicted results has shown the HZO- $ Fe$ offers superior improvement in sub-threshold slope (SS), peak-transconductance (g $ _{m}$ ) and off-current (I $_{\text{OFF}}$ ) at lower $ t_{Fe}$ with the expense of lower endurance to hysteresis. On the other hand, the HSO- $ Fe$ predicts improvement in SS, peak-g $ _{m}$ and I $_{\text{OFF}}$ with higher endurance towards hysteresis in-spite of $ t_{Fe}$ thickness under sub-10 nm regime. Similarly, the V $_{\mathrm{B}}$ variation have shown similar results where the HSO NCFET has predicted slightly higher enhancement in performance aspect than HZO NCFET owing to the V $_{\text{TH}}$ shift phenomena attributed to FDSOI architecture and HSO- $ Fe$ comprehensible polarization duality.

A miniaturized helical antenna is presented in this work. The antenna is flexible, it is 6100 μm long and it has a diameter of 352 μm. This antenna has such a small cross-section, that permits to be implanted in the human body with fine syringes and minimally invasive surgeries. The antenna can be used to receive power and/or send information in medical devices. The antenna is made of biocompatible materials: polytetrafluoroethylene (PFTE) and copper. The fundamental parameters of the antenna have been simulated and experimentally measured in animal human-like tissues, showing good agreement. The resonant frequency of the antenna is 4.7 GHz, with a reflection coefficient of −25.1 dB, and a gain of −4.7 dBi. As expected, the resonant frequency decreases inside biological tissues comparing to the free-space open-air measurement. Reducing the resonant frequency is an advantage because power signals can penetrate deeper into body tissues.

This work reports the synthesis of copper oxide (CuO) nanowires (NWs) using thermal oxidation followed by microcantilever contact print ( $\mu$ CCP) of silver nanoparticles (AgNP) on Si-SiO $_{2}$ substrate to get field-effect transistors (FETs) in back, coplanar, and top gate configurations. CuO single NWs (SNWs) FETs with channel lengths 10–50 $\mu$ m, and diameter 200–250 nm are fabricated and characterized to understand the transport properties of SNW devices. The fabricated FETs exhibit p-type conduction with hole mobility 0.14–0.36 cm $^{2}$ V $^{-1}$ s $^{-1}$ and the hole concentration in dark and photo-excitation found to be in the range of 10 $^{16}$ –10 $^{17}$ cm $^{-3}$ and 10 $^{17}$ –10 $^{19}$ cm $^{-3}$ , respectively. The developed CuO SNW two-terminal and FETs are used to detect the white light at room temperature and ethanol at 150 $^{\circ }$ C. The FETs have limited performance but are stable for months.

Terahertz (THz)-band nanocommunication is envisioned to revolutionize the future of wireless communications by enabling applications in nanoscale domains such as the Internet of Nanothings, wireless on-chip communications, and advanced health monitoring. However, communication between nanodevices is hindered by the highly frequency-selective and distance-dependent nature of the THz channel, which ultimately restricts nanocommunication distances to a few millimeters. Moreover, attempts by multiple nanodevices to access the channel simultaneously increase the interference in the overall communication system. In this study, a new pulse-based modulation scheme for nanonetworks called time-hopping multilevel pulse position modulation (TH ML-PPM) is proposed and its performance in a multiuser nanocommunication scenario is analyzed. In ML-PPM, each nanomachine in the nanonetwork first transforms the transmitted bits into multilevels by using several orthogonal codes and then modulates each multilevel code into a pulse position. The generated ML-PPM signal is subsequently time-hopped to achieve multiple access. Employing orthogonal coding results in spreading gain at the nanoreceiver, which improves the performance of the proposed scheme. The bit error rate and link capacity of the time-hopped multilevel PPM scheme are evaluated for different THz propagation conditions and system design parameters. The results show that for a THz channel with 10% water vapor concentration, a link capacity of more than 100 gigabits per second is achieved across a transmission distance of $0.5 \,\mathrm{m}\mathrm{m}$ .

Organic field-effect transistors (OFETs) have shown potential market in many low-power sensing applications. Toward that, the fabrication of sharp on/off OFET is essential. Herein, we present an attempt to fabricate OFET using polyaniline (PANI), in the form of PANI-nanofibers with a fiber diameter of 75 nm, as an active semiconductor layer. The polymethyl methacrylate (PMMA) is utilized as a gate dielectric with an aluminum bottom electrode. Top electrodes for both source and drain were fabricated of gold. The Primary, in-situ polymerization method is used in preparing the PANI as a semiconductor film. The morphological and optical properties of PANI nanofibers, as well as PMMA oxide thin-film, were investigated using SEM, FTIR, AFM, and UV-Vis. Spectrometer. The bandgap energy was observed to be 2.2 eV. Consequently, the I-V characteristics were studied for the device, showing a sharp sub-threshold response. An ultra-low threshold voltage of 0.17 V was recorded, promoting the fabricated devices for various sensing applications.

For the theoretical investigation of stanene nanoribbons (SnNRs) as metal interconnect, first principles calculations are carried out using density functional theory (DFT). The structural, electronic, and transport characteristics of SnNRs with hydrogen/fluorine (H/F) edge passivations are evaluated. Computations of the binding energy ( $E_{b}$ ) and formation energy ( $E_{forn}$ ) show that fluorination enhances the thermodynamic stability of SnNRs. The considered SnNRs are observed to be metallic from the bandstructure and density of states computations. Owing to the metallicity, SnNRs are proposed for nanoscale metal interconnect applications. For the quantum transport computations, the non-equilibrium Green's function (NEGF) formalism is used. Current-voltage ( $I$ - $V$ ) characteristics are linear for both edge hydrogenated (H-SnNR-H) and both edge fluorinated (F-SnNR-F) SnNRs. Typical parasitic parameters that influence the nanoscale interconnect performance such as quantum resistance ( $R_{Q}$ ), quantum capacitance ( $C_{Q}$ ), and kinetic inductance ( $L_{K}$ ) are evaluated. Further, the small scale driver-interconnect-load (DIL) circuit model of the SnNR nanoribbons is considered to evaluate the interconnect performance. Performance metrics such as delay ( $\tau _{delay}$ ), power delay product ( $PDP$ ), stability, frequency response analysis, and crosstalk effect are evaluated for H-SnNR-H and F-SnNR-F interconnects. Thus, the obtained findings suggest that SnNRs can be considered as promising candidates for nanoscale metal interconnect applications.

We propose nano flex film, a commercially available mobile screen protector, as a prospective flexible substrate for piezotronic devices. Reliable fabrication methods on flexible substrates and robust testing methods are essential to explore piezotronic properties in emerging 2D materials. Unlike conventional rigid substrates, flexible substrates are challenging to handle during fabrication and subsequent testing. The fabrication process on the proposed flexible substrate is as seamless as on rigid substrates. The optimized methods to fabricate 2D material devices on nano flex films are presented. Inorganic dielectric materials such as silicon dioxide (SiO 2 ) offer good adhesion, better lifetime, and optical contrast to the 2D material flakes compared to polymer alternatives. The devices made on nano flex films with SiO 2 have shown almost three-fold improvement in open circuit voltage generated (50 mV) and strain gauge values (1997 at 0.44% strain). Also, a simple setup proposed for strain-dependent electrical measurements enables us to characterize the piezotronic properties of different 2D materials without wire bonding or probe needles.

This article presents the design of a fully-custom integrated circuit (IC) suitable for adjusting the complex impedance of individual meta-atoms to enable programmability of metasurface systems. Implemented in a 0.18 μm mixed-signal CMOS process, the circuit utilizes four integrated complex impedance elements, each one with 2 16 available states. The impedance elements are optimized between 2–6 GHz, thus covering the entire S-band as well as half of the C-band. An asynchronous digital control circuit based on Quasi Delay Insensitive (QDI) circuits has been employed, offering basic communication capabilities and software programmability, but most importantly, the clockless operation allows for extreme scalability, ultra-low static power consumption and low electromagnetic (EM) radiated emissions. An array of meta-atoms utilizing the ICs can form metasurfaces with arbitrary sizes and shapes, on both rigid and flexible substrates, adjusting their surface impedance without interfering with incoming EM waves. Measurement results of the 2.2 mm × 2.2 mm IC demonstrate that it achieves a reconfiguration frequency of 1 MHz for all loading elements, whilst consuming 324 μW static power consumption.

Compact slow light devices are essential components for performing data caching and signal processing in photonic integrated loops. In this article, an integrated ultra-low-dispersion slow light device with a novel method is proposed. The device consists of three parts (hexagonal resonator with elliptical core, stub cavity, and tooth cavities) coupled to the waveguide, respectively. Dual Fano resonances occur in the structure, and transmission characteristics of the structure are investigated in detail by temporal coupled-mode theory. Finite-difference time-domain simulations reveal that the transmission bandwidth, group index, and delay time can be manipulated by adjusting the separation between two Fano resonances, which is related to the eccentricity of the oval core. At the 850.7 nm window, transmission bandwidth and average group index are optimized to 21.1 nm and 12.19, respectively. Moreover, multiple dispersionless wavelengths within the slow light bandwidth are obtained based on dual Fano resonances. Furthermore, feasibility of the device to perform slow light function in different channels is researched, and device performance is presented and analyzed. This device has a great impact on improving the quality of signals on chips, and the method introduced is of great significance for designing other photonic devices.

A leap towards deriving a robust-compact model for ferroelectric-FET (FeFET) oscillator based spiking neurons has been developed. The compact model can capture and emulate neurons that exhibit both excitatory and inhibitory coupled dynamical behaviour, native to cortical neurons. The proposed model can reliably mimic neuronal dynamics for a broad-spectrum of FeFETs when, factored with appropriate validation of numerical simulations and physics-based models. The emulation of neuronal attributes based on FDSOI FeFET having qualitative agreement with previously reported data. The robustness of this analytical model has been investigated by tuning with ferro-dielectric (Fe) materials i.e., zirconium-doped HfO 2 (HZO) and silicon-doped HfO 2 (HSO) for mimicking the neurons. In continuance, the model is examined for emulating the cortical neurons by altering the inhibition (high-V GF ) and excitation (low-V GF ) inputs with a suitable frequency of operation for spiking neurons.

An efficient light management technique is proposed and investigated by developing a TCAD model for microcrystalline silicon based thin film solar cell. The model includes physical insight related to some optical phenomenon like scattering and diffusive reflection of light as well as some electrical phenomena like carrier transport at the heterointerfaces. Two different structures, which comprises of sawtooth and grating-type back nanotextured in combination with random front nano-textured absorber layers are considered in this work. It has been observed that sawtooth or grating type back nano-textured absorber layer results in enhanced absorption of incident photons as compared to the planar back absorber layer. Also, the grating type back-textured absorber provides better performance compared to its sawtooth counterparts. Finally, the depth and period of grating are optimized in order to maximize the power conversion efficiency of grating-back-textured with random-front-textured absorber. The optimized structure results in an efficiency of 12.325% which corresponds to an improvement of 3.975% compared to the random front and back nano-textured thin film solar cell.