Effect Of Dielectric Thickness Research Articles

Enhanced Long-Range Surface Plasmon Effect Based on Zr2CO2 MXene and MoSe2 Heterostructures for SPR Biosensors With High FOM

MXenes-based van der Waals heterojunction materials with excellent chemical stability and bioaffinity have been widely used in biosensing in recent years. We propose a new MoSe2@Zr2CO2 heterostructure as a long-range surface plasmon resonance (LRSPR) sensor based on the Kretschmann configuration from simulation and optimize the structure parameters algorithmically. First, we investigate the effect of different layers of MoSe2@Zr2CO2 heterojunction on the LRSPR wave. The results show that the optimal number of layers for heterogeneous layers is 18. Second, the effects of dielectric thickness and refractive index (RI) on sensitivity are investigated in depth, and optimized structural parameters are obtained. Finally, the effect of prisms with different refractive coefficients on the sensor performance is also discussed, and it is shown that prisms with lower refractive coefficients can effectively improve the sensitivity performance of the sensor. The sensor response performance to biomolecules is greatly enhanced due to the gain of light absorption and SPR. Compared with the conventional precious metal Au-based (50 nm) thin-film SPR sensor, the figure of merit (FOM) of the sensor is improved by a factor of 8.16, and higher sensitivity (92.48°/RIU) and quality factor (QF) (319.63 RIU−1) are obtained in the visible range.

Effect of Dielectric Thickness on Resistive Switching Polarity in TiN/Ti/HfO2/Pt Stacks

In recent years, several materials and metal-insulator-metal devices are being intensively studied as prospective non-volatile memories due to their resistive switching effect. In this work, thickness-dependent resistive switching polarity was observed in TiN/Ti/HfO2/Pt structures as the sign of the voltages at which SET and RESET occur depended on the film thickness. A thorough revision of the previous literature on bipolar resistive switching polarity changes is made in order to condense previous knowledge of the subject in a brief and comprehensible way and explain the experimental measurements. The different resistive switching polarities occur in a similar voltage range, which is a new finding when compared to precedent research on the subject. A hypothesis is proposed to explain the change in resistive switching polarity, based on the assumption that polarity change is due to filament disruption occurring at different interfaces.

Effect of dielectric thickness on MgZnO Thin Film Transistor characteristics

From past ten years, low-k dielectric was used as dielectric material in Thin Film Transistors Technology.Reduction of dimension of device can be done with the reduction the thickness of dielectric material and active layer. Due to reduction in thickness of dielectric material capacitances increases therefore drain current increases. But further more reduction in dielectric material leads to leakage current which effect other parameter like threshold voltage. To enhance performance of transistors without reduction in thickness of dielectric material use high-k dielectric material so overall capacitances increases and decrease leakage current. In this paper the parameters of the MgxZn1−x thin film transistors are compared. Composition of Mg in ZnO used because high direct bandgap (7.7 eV). Due to composition of Mg into ZnO that affects the electrical parameter of a transistor. MgxZn1−x (x = 20% and 1-x = 80%) Thin film transistor’s electrical performance with high-k (Al2O3(K ∼ 9)) dielectric materials thickness is measured. Variation in thickness of high-k dielectric is taken as 150 nm, 100 nm, 50 nm, 20 nm. Electrical characteristics are good for 20 nm thickness of Al2O3 dielectric material. Optimized electrical parameter of transistor like threshold voltage, mobility, and on/off ratio are 0.59 V, 9.62 cm2/V.s, and 1010 observed after simulation on TCAD. Results shows that this type of results for Thin film Transistors are used in photodetector application.

A Compact Model of Gate Capacitance in Ballistic Gate-All-Around Carbon Nanotube Field Effect Transistors

This paper presents a one-dimensional analytical model for calculating gate capacitance in Gate-All-Around Carbon Nanotube Field Effect Transistor (GAA-CNFET) using electrostatic approach. The proposed model is inspired by the fact that quantum capacitance appears for the Carbon Nanotube (CNT) which has a low density of states. The gate capacitance is a series combination of dielectric capacitance and quantum capacitance. The model so obtained depends on the density of states (DOS), surface potential of CNT, gate voltage and diameter of CNT. The quantum capacitance obtained using developed analytical model is 2.84 pF/cm for (19, 0) CNT, which is very close to the reported value 2.54 pF/cm. While, the gate capacitance comes out to be 24.3×10-2 pF/cm. Further, the effects of dielectric thickness and diameter of CNT on the gate capacitance are also analysed. It was found that as we reduce the thickness of dielectric layer, the gate capacitance increases very marginally which provides better gate control upon the channel. The close match between the calculated and simulated results confirms the validity of the proposed model.

Effect of film thickness and temperature on the resistive switching characteristics of the Pt/HfO2/Al2O3/TiN structure

Thin films with HfO2/Al2O3 laminated structure were prepared by the ALD method in this paper. Typical bipolar resistance switching characteristics were observed in the Pt/HfO2/Al2O3/TiN structure device. The samples were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The effects of dielectric thickness and different test temperatures on the electrical performance were investigated. Experiments show that when the thickness of HfO2/Al2O3 is 7 nm/3 nm, the electrical properties are the best. As the test temperature increases, the resistance values (RLRS and RHRS) of the Pt/HfO2/Al2O3/TiN structure fluctuate more and more. When the test temperature approaches the failure temperature, the device's transition voltages (VSet and VReset) will also become more volatile.

Effects of dielectric thickness on energy storage properties of surface modified BaTiO3 multilayer ceramic capacitors

Surface modified BaTiO3 were synthesized by coating BaTiO3 particles of 50/230 nm average grain size with 3 wt% Al2O3 and 1 wt% SiO2 (BTAS5/BTAS1). Multilayer ceramic capacitors (MLCC) were fabricated via two-steps sintering method. After sintering, average grain size (G) of BTAS5/BTAS1 MLCC slightly increased to 106/273 nm. Compared to BTAS1, BTAS5 MLCC with finer grains possessed higher breakdown strength (BDS), discharge energy density (Udischarge) and discharge/charge efficiency (Eeff). Moreover, great enhancement of BDS from 265 kV/cm to 651 kV/cm was obtained as dielectric thickness (D) of BTAS5 MLCC decreased from 68 μm to 19 μm, resulting in improvement of maximum discharge energy density (Umax) from 1.29 J/cm3 to 4.00 J/cm3. Linear relationship between power index of dielectric thickness and breakdown strength was observed, which could be described as BDS∝D-0.397. The results matched the model of Forlani and Minnaja well, with regard to the volume effects. Because of their low-cost, easily fabrication, lead-free, enhanced breakdown strength and improved discharge energy density, surface modified BaTiO3 multilayer ceramic capacitors can provide realistic solutions for high power energy storage applications.

MoM analysis of cavity‐backed annular conical antennas

This study presents theoretical formulation and results for cavity-backed annular conical antennas. The formulation is based on equivalence principle and method of moments (MoM), in both point-matching and Galerkin forms. Results are presented for radiation diagram, and input impedance, and compared to those obtained using commercial software. The effects of dielectric thickness and of cavity dimensions on input impedance are presented. In addition, the feeding using two coaxial cables for radiation maximum at cone axis is also presented.

Effects of dielectric thickness on optical behavior and tunability of one-dimensional Ag/SiO₂ multilayered metamaterials.

We fabricated one-dimensional periodic multilayered metamaterial structures consisting of Ag and SiO₂alternating layers. Optical responses, such as transmission and absorption, are consistent well within finite difference time domain (FDTD) simulations. Angle dependent real and imaginary dielectric permittivity reflection spectra demonstrate their operational capability in the visible wavelength region. This multilayer metamaterial can be converted into a photonic crystal by manipulating the thickness of SiO₂ and we demonstrate that proper filling of SiO₂/Ag layers the operating wavelength can be tuned to higher wavelength region. However, absolute value of transmission reduces with increasing number of multilayer pairs due to metal absorption.

A systematic reliability investigation of the dielectric charging process in electrostatically actuated MEMS based on Kelvin probe force microscopy

This paper presents a comprehensive investigation for the dielectric charging problem in electrostatically actuated microelectromechanical system (MEMS) devices. The approach is based on Kelvin probe force microscopy (KPFM) and targets, in this specific paper, thin PECVD silicon nitride films for electrostatic capacitive RF MEMS switches. KPFM has been employed in order to mimic the potential induced at the dielectric surface due to charge injection through asperities. The effect of dielectric thickness has been investigated through depositing SiNx films with different thicknesses. Then, in order to simulate the different scenarios of dielectric charging in real MEMS switches, SiNx films have been deposited over thermally grown oxide, evaporated gold and electroplated gold layers. Also, the effect of the deposition conditions has been investigated through depositing dielectric films using low and high frequency PECVD methods. The investigation reveals that thin dielectric films have larger relaxation times compared to thick ones when the same injection bias is applied, independently of the substrate nature. For the same SiNx film thickness, the decay time constant is found to be smaller in dielectric films deposited over metallic layers compared to the ones deposited over silicon substrates. Finally, the material stoichiometry is found to affect the surface potential distribution as well as the relaxation time constant.

Effects of dielectric thickness and contact area on current–voltage characteristics of thin film metal–insulator–metal diodes

Planar asymmetric Ni–NiO–Cr/Au thin film Metal–Insulator–Metal (MIM) tunnel diodes were fabricated for use in an ultra-sensitive infrared detector operating at room temperature. MIM diodes with contact areas of 100 μm 2 and 1 μm 2 were fabricated using standard Micro-Electro Mechanical Systems techniques. A linear relationship between the thickness of reactively sputtered Nickel Oxide (NiO) and the breakdown voltage was experimentally determined, and the diode performance was verified using a theoretical approach. Current–Voltage measurements of the MIM diode revealed an increase in the current from 1.5 nA to 0.8 mA, when the thickness of the dielectric and the contact area of the detector decreased. Also, the rectification ratios of the detectors were determined, exhibiting an asymmetry of 4.5 at 1 V and 6 at 0.2 V for detectors A and B, respectively. Further, the ratio was observed to be increasing with bias voltage suggesting a strong asymmetric behavior. The results are in agreement with the theoretical predictions confirming conduction via tunneling. The nonlinearity and asymmetry exhibited by these diodes suggests their viability in infrared applications.