Tuning Characteristics of AlN-Based Piezoelectric Micromachined Ultrasonic Transducers Using DC Bias Voltage

2022 ◽  
pp. 1-7
Author(s):  
Zhipeng Wu ◽  
Wenjuan Liu ◽  
Zhihao Tong ◽  
Yao Cai ◽  
Chengliang Sun ◽  
...  
Keyword(s):  
Bias Voltage ◽  
Ultrasonic Transducers ◽  
Dc Bias

scholarly journals Investigation of the Carrier Movement through the Tunneling Junction in the InGaP/GaAs Dual Junction Solar Cell Using the Electrically and Optically Biased Photoreflectance Spectroscopy

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 638
Author(s):  
Sanam SaeidNahaei ◽  
Hyun-Jun Jo ◽  
Sang Jo Lee ◽  
Jong Su Kim ◽  
Sang Jun Lee ◽  
...  
Keyword(s):  
Solar Cell ◽  
Electric Field ◽  
Electric Fields ◽  
Bias Voltage ◽  
Tunnel Junction ◽  
Photogenerated Carrier ◽  
Internal Electric Field ◽  
Junction Solar Cell ◽  
Photoreflectance Spectroscopy ◽  
Dc Bias

For examining the carrier movements through tunnel junction, electrically and optically-biased photoreflectance spectroscopy (EBPR and OBPR) were used to investigate the internal electric field in the InGaP/GaAs dual junction solar cell at room temperature. At InGaP and GaAs, the strength of p-n junction electric fields (Fpn) was perturbed by the external DC bias voltage and CW light intensity for EBPR and OBPR experiments, respectively. Moreover, the Fpn was evaluated using the Fast Fourier Transform (FFT) of the Franz—Keldysh oscillation from PR spectra. In the EBPR, the electric field decreased by increasing the DC bias voltage, which also decreased the potential barrier. In OBPR, when incident CW light is absorbed by the top cell, the decrement of the Fpn in the GaAs cell indicates that the photogenerated carriers are accumulated near the p-n junction. Photogenerated carriers in InGaP can pass through the tunnel junction, and the PR results show the contribution of the modification of the electric field by the photogenerated carriers in each cell. We suggest that PR spectroscopy with optical-bias and electrical-bias could be analyzed using the information of the photogenerated carrier passed through the tunnel junction.

scholarly journals An Integrated Front-end Circuit Board for Air-Coupled CMUT Burst-Echo Imaging

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6128
Author(s):  
Lei Ye ◽  
Jian Li ◽  
Hui Zhang ◽  
Dongmei Liang ◽  
Zhuochen Wang
Keyword(s):  
Imaging System ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Ultrasonic Transducers ◽  
Circuit Board ◽  
Capacitive Micromachined Ultrasonic Transducers ◽  
Front End ◽  
Field Programmable ◽  
Good Potential ◽  
Dc Bias

To conduct burst-echo imaging with air-coupled capacitive micromachined ultrasonic transducers (CMUTs) using the same elements in transmission and reception, this work proposes a dedicated and integrated front-end circuit board design to build an imaging system. To the best of the authors’ knowledge, this is the first air-coupled CMUT burst-echo imaging using the same elements in transmission and reception. The reported front-end circuit board, controlled by field programmable gate array (FPGA), consisted of four parts: an on-board pulser, a bias-tee, a T/R switch and an amplifier. Working with our 217 kHz 16-element air-coupled CMUT array under 100 V DC bias, the front-end circuit board and imaging system could achieve 22.94 dB signal-to-noise ratio (SNR) in burst-echo imaging in air, which could represent the surface morphology and the three-dimensional form factor of the target. In addition, the burst-echo imaging range of our air-coupled CMUT imaging system, which could work between 52 and 273 mm, was discussed. This work suggests good potential for ultrasound imaging and gesture recognition applications.

Frequency and dc bias voltage dependent dielectric properties and electrical conductivity of BaTiO3SrTiO3/(SiO2)x nanocomposites

2019 ◽  
Vol 45 (9) ◽  
pp. 11989-12000 ◽  
Author(s):  
Y. Slimani ◽  
B. Unal ◽  
E. Hannachi ◽  
A. Selmi ◽  
M.A. Almessiere ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Properties ◽  
Bias Voltage ◽  
Voltage Dependent ◽  
Dc Bias

scholarly journals Critical Parameters and Influence on Dynamic Behaviours of Nonlinear Electrostatic Force in a Micromechanical Vibrating Gyroscope

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Shuying Hao ◽  
Yulun Zhu ◽  
Yuhao Song ◽  
Qichang Zhang ◽  
Jingjing Feng ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Bias Voltage ◽  
Electrostatic Force ◽  
Dynamic Performance ◽  
Great Influence ◽  
Critical Parameters ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Element Analysis ◽  
Dc Bias

The electrostatic force nonlinearity caused by fringe effects of the microscale comb will affect the dynamic performance of the micromechanical vibrating gyroscopes (MVGs). In order to reveal the influence mechanism, a class of four-degree-of-freedom (4-DOF) electrostatically driven MVG is considered. The influence of DC bias voltage and comb spacing on the nonlinearity of electrostatic force and the dynamic response of the MVG by using multiple time scales method and numerical simulation are discussed. The results indicate that the electrostatic force nonlinearity causes the system to show stiffness softening. The softening characteristics of the electrostatic force cause the offset of the resonance frequency and a decrease in sensitivity. Although the electrostatic nonlinearity has a great influence on the dynamic behaviour, its influence can be avoided by the reasonable design of the comb spacing and DC bias voltage. There exists a critical value for comb spacing and DC bias voltage. In this paper, determining the critical values is demonstrated by nonlinear dynamics analysis. The results can be supported by the finite element analysis and numerical simulation.

Zirconia Coatings Deposited by Inductively Coupled Plasma Assisted CVD

1998 ◽  
Vol 555 ◽  
Author(s):  
P. Colpo ◽  
G. Ceccone ◽  
B. Leclercq ◽  
P. Salvatore ◽  
F. Rossi
Keyword(s):  
Thin Films ◽  
Bias Voltage ◽  
Inductively Coupled Plasma ◽  
Gas Mixture ◽  
Negative Bias ◽  
Negative Bias Voltage ◽  
Inductively Coupled ◽  
Deposition Parameters ◽  
Coating Characteristics ◽  
Dc Bias

AbstractThin films of zirconia have been deposited by an Inductively Coupled Plasma Assisted CVD (ICP-PACVD) reactor from tetra (tert-butoxy)-zircon precursor diluted in Ar and O2 gas mixture. An independent RF generator is used to control carefully the substrate negative bias voltage during the deposition. Zirconia thin films, with thickness up to 10 microns were deposited on Si (100) polished wafers under different plasma conditions. Correlation between deposition parameters, and microstructure has been established showing that the ion bombardment has a large influence on the coating characteristics. In particular, the possibility of tailoring mechanical properties of the films by controlling the applied DC bias voltage is discussed.

scholarly journals Field-enhanced bulk conductivity and resistive-switching in Ca-doped BiFeO3 ceramics

2014 ◽  
Vol 16 (36) ◽  
pp. 19408-19416 ◽  
Author(s):  
Nahum Masó ◽  
Héctor Beltrán ◽  
Marta Prades ◽  
Eloisa Cordoncillo ◽  
Anthony R. West
Keyword(s):  
Bias Voltage ◽  
Resistive Switching ◽  
Room Temperature ◽  
Bulk Conductivity ◽  
Dc Bias

The conductivity at room temperature of Ca-doped BiFeO3 ceramics increases reversibly under the influence of a small dc bias voltage.

Nonequilibrium Green’s Function Approach to Dynamic Properties of Resonant-Tunneling through Double-Barrier Structures

1992 ◽  
Vol 06 (07) ◽  
pp. 1099-1118
Author(s):  
L.Y. Chen ◽  
C.S. Ting
Keyword(s):  
Green’S Function ◽  
Bias Voltage ◽  
Green's Function ◽  
Resonant Tunneling ◽  
Dynamic Properties ◽  
Function Technique ◽  
Double Barrier ◽  
Nonequilibrium Green's Function ◽  
Dc Bias ◽  
Nonequilibrium Green’S Function

In this paper, we review a recently developed approach to the dynamic properties of double barrier resonant tunneling systems, based on the nonequilibrium Green’s function technique and the Feynman path integral theory. The transient behavior of tunneling current, immediately after the switch-on of a dc bias voltage, is characterized by the building up process of tunneling electrons in the quantum well. The novel negative differential conductance demonstrates itself as a function of frequency of the small ac signal imposed upon a dc bias. The imaginary part of admittance is shown to be related to the conductance via a Kronig-Kramers relation. The noise characteristics clearly demonstrate a strong time correlation derived from the Pauli exclusion principle and have evident dependence upon the structure parameters and the bias voltage. All those theoretical results are compared with experiments and numerical simulations.

Single Wafer, Anisotropic Etching of Polysilicon with C12/SF6 and Trielectrode Reactor Operation

1986 ◽  
Vol 68 ◽  
Author(s):  
James E. Nulty
Keyword(s):  
Bias Voltage ◽  
Etch Rate ◽  
Proximity Effects ◽  
The Self ◽  
Rf Power ◽  
Reactor Operation ◽  
Lower Electrode ◽  
Dc Bias ◽  
Bias Versus ◽  
Etching System

AbstractA totally anisotropic, highly selective dry poly etch process has been developed that is capable of etching sub-2.0 micron linewidths.Doped poly etch rates of 10,000 A/min.are obtained using C12-only chemistry.Standard novolac or bilevel photoresist is used, depending on the lithography requirements.Anisotropy is achieved without the use of carbon-containing gases; as a result, minimal proximity effects are observed between dense and stand alone etched lines.Wafer maps of etched linewidths on 4-inch wafers are presented, showing mask to final bias and uniformity results.A commercially available triode dry etching system was used for the work.The self-induced dc bias voltage can be selected regardless of the applied rf power.The effect of variable self-induced dc bias versus applied rf power is presented for selectivity, upper and lower electrode interactions, and etch rate uniformity.Characterization by the use of spectroscopy is also presented, showing changes due to varying the self-induced dc bias at a constant rf power.

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