Propagation characteristics of surface plasmon waves on Au, Ag and Al at optical wavelengths

In this paper the propagation characteristics of Surface Plasmon Waves (SPWs) which exists on noble metals like gold (Au), silver (Ag) and aluminium (Al) due to the formation of Surface Plasmon Polaritons (SPPs), have been evaluated theoretically and simulated with the help of MATLAB programming language. The variation of the propagation constant, the attenuation coefficient and penetration depth inside the metal and the dielectric has been evaluated. The variations of the spot size width with the propagating wavelength also have been determined for the metals. It has been found that highly conducting metals Au and Ag provide a strong confinement to the SPWs than Al at optical frequencies as the spot size width of the former is found to be nearly 10 µm less than that of the later. The comparative study reveals that metal having higher conductivity can support a more confined SPW, having a lower penetration depth than metals of lower conductivity at terahertz frequencies when its dielectric constant assumes a negative value. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2790

A Comparative Study between Silicon Carbide and Silicon Nitride based Single Cell CMUT

This research explores the design and conducts a comparative analysis of a noninsulated Capacitive Micromachined Ultrasonic Transducer (CMUT) featuring an innovative asymmetric electrode configuration to improve the performance of the device. Specifically, this configuration involves the utilization of a top electrode with a smaller radius in comparison to the bottom electrode. The study encompasses an investigation into the effects of varying biasing voltage within the range of 40 V to 100 V. The materials employed in this study are carefully selected to optimize the CMUT's performance. The substrate material is silicon, and the bottom and top electrodes are made from aluminium. Additionally, silicon dioxide is utilized as the foundation material within the device's structure.Comment: copyright (2023) Inventive Research Organization. This is an open access article under the Creative Commons Attribution-NonCommercial International (CC BY-NC 4.0) License. This is a "Preprint" version of the main publication, published copy of the article can be accessed from the publisher's directory (DOI: 10.36548/jei.2023.3.006

Study of Interface Charge Densities for ZrO 2

A thickness-dependent interfacial distribution of oxide charges for thin metal oxide semiconductor (MOS) structures using high-k materials ZrO2 and HfO2 has been methodically investigated. The interface charge densities are analyzed using capacitance-voltage (C-V) method and also conductance (G-V) method. It indicates that, by reducing the effective oxide thickness (EOT), the interface charge densities (Dit) increases linearly. For the same EOT, Dit has been found for the materials to be of the order of 1012 cm−2 eV−1 and it is originated to be in good agreement with published fabrication results at p-type doping level of 1×1017 cm−3. Numerical calculations and solutions are performed by MATLAB and device simulation is done by ATLAS

Silicon carbide membranes for microelectromechanical systems based cmut with influence factors

Microelectromechanical Systems (MEMS) based capacitive micromachined ultrasonic transducer (CMUT) has many applications in medical imaging. Ultrasonic transducer technology has been long dominated by piezoelectric transducers, particularly in the medical ultrasound imaging. The best popular materials used for fabricating CMUT membranes are silicon nitride (Si 3 N 4 ), polysilicon, chromium and aluminum are characteristically used to shape electrodes on top of these membranes. But current technology of CMUT demands the silicon carbide (SiC) for membrane material where the electrode instead of being on top of the membrane is placed beneath the membrane. It offers greatest contiguity of the upper and subordinate electrodes. For this it decreases the transduction gap enlightening the electro-mechanical coupling and sensitivity of the device. Aside from this, it is reported that the CMUT has a resonance frequency of 1.7 MHz and a 3 dB-bandwidth of 0.15 MHz. Also, the higher Young’s modulus (260 GPa) of SiC with its little residual stress (± 30 MPa). Consequences in great strength and resilient CMUT membranes, which led to the studies presented in this paper. All the results are validated by FEM simulation

Squeeze Film Effect in Surface Micromachined Nano Ultrasonic Sensor for Different Diaphragm Displacement Profiles

In the present paper, we have analytically explored the small variations of the local pressure in the trapped air film of both sides of the clamped circular capacitive micromachined ultrasonic transducer (CMUT), which consists of a thin movable membrane of silicon nitride (Si3N4). This time-independent pressure profile has been investigated thoroughly by solving the associated linear Reynold's equation in the framework of three analytical models, viz. membrane model, plate model, and non-local plate model. The solution involves Bessel functions of the first kind. The Landau-Lifschitz fringing technique has been assimilated to engrave the edge effects in estimation of the capacitance of CMUT, which should be considered in the micrometer or lesser dimension. To divulge the dimension-based efficacy of the considered analytical models, various statistical methods have been employed. Our use of contour plots of absolute quadratic deviation revealed a very satisfactory solution in this direction. Though the analytical expression of the pressure profile is very cumbersome in various models, the analysis of these outputs exhibits that the pressure profile follows the displacement profile in all the cases indicating no viscous damping. A finite element model (FEM) has been used to validate the systematic analyses of displacement profiles for several radii and thicknesses of the CMUT's diaphragm. The FEM result is further corroborated by published experimental results bearing excellent outcome