Low-voltage pulse exciting electron emission from ferroelectric copolymer film cathode: Role of film thickness and emission stability

2010 ◽  
Vol 256 (21) ◽  
pp. 6433-6436
Author(s):  
J.J. Li ◽  
C. Lu ◽  
X.X. Xia ◽  
C.Z. Gu
Keyword(s):  
Film Thickness ◽  
Electron Emission ◽  
Voltage Pulse ◽  
Low Voltage ◽  
Copolymer Film ◽  
Emission Stability ◽  
Exciting Electron

SEM analysis of DC magnetron sputtered beryllium films

1988 ◽  
Vol 46 ◽  
pp. 960-961
Author(s):  
E. F. Lindsey ◽  
C. W. Price ◽  
E. L. Pierce ◽  
E. J. Hsieh
Keyword(s):  
Fine Structure ◽  
Electron Emission ◽  
Secondary Electron ◽  
Low Voltage ◽  
Ion Beam ◽  
Secondary Electron Emission ◽  
Sem Analysis ◽  
Fused Silica ◽  
Grain Structure ◽  
Silica Substrate

Columnar structures produced by DC magnetron sputtering can be altered by using RF biased sputtering or by exposing the film to nitrogen pulses during sputtering, and these techniques are being evaluated to refine the grain structure in sputtered beryllium films deposited on fused silica substrates. Beryllium is brittle, and fractures in sputtered beryllium films tend to be intergranular; therefore, a convenient technique to analyze grain structure in these films is to fracture the coated specimens and examine them in an SEM. However, fine structure in sputtered deposits is difficult to image in an SEM, and both the low density and the low secondary electron emission coefficient of beryllium seriously compound this problem. Secondary electron emission can be improved by coating beryllium with Au or Au-Pd, and coating also was required to overcome severe charging of the fused silica substrate even at low voltage. The coating structure can obliterate much of the fine structure in beryllium films, but reasonable results were obtained by using the high-resolution capability of an Hitachi S-800 SEM and either ion-beam coating with Au-Pd or carbon coating by thermal evaporation.

scholarly journals Hematite photoelectrodes for water splitting: evaluation of the role of film thickness by impedance spectroscopy

2014 ◽  
Vol 16 (31) ◽  
pp. 16515 ◽  
Author(s):  
Tânia Lopes ◽  
Luísa Andrade ◽  
Florian Le Formal ◽  
Michael Gratzel ◽  
Kevin Sivula ◽  
...  
Keyword(s):  
Impedance Spectroscopy ◽  
Film Thickness ◽  
Water Splitting

Fundamental Study of Cannabidiol Effect on MCF-7 with Low Voltage Pulse Electric Field

2021 ◽  
Author(s):  
Nur Adilah Abd Rahman ◽  
Muhammad Mahadi Abdul Jamil ◽  
Mohamad Nazib Adon ◽  
Ahmad Basri Zainal ◽  
Farideh Javid ◽  
...  
Keyword(s):  
Electric Field ◽  
Voltage Pulse ◽  
Low Voltage ◽  
Pulse Electric Field ◽  
Fundamental Study ◽  
Pulse Electric ◽  
Mcf 7

scholarly journals Thin-film chemical expansion of ceria based solid solutions: laser vibrometry study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hendrik Wulfmeier ◽  
Dhyan Kohlmann ◽  
Thomas Defferriere ◽  
Carsten Steiner ◽  
Ralf Moos ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
High Temperature ◽  
Film Thickness ◽  
Solid Solutions ◽  
Low Voltage ◽  
Excitation Frequency ◽  
Dimensional Change ◽  
Potential Core ◽  
Chemical Expansion

Abstract The chemical expansion of Pr0.1Ce0.9O2–δ (PCO) and CeO2–δ thin films is investigated in the temperature range between 600 °C and 800 °C by laser Doppler vibrometry (LDV). It enables non-contact determination of nanometer scale changes in film thickness at high temperatures. The present study is the first systematic and detailed investigation of chemical expansion of doped and undoped ceria thin films at temperatures above 650 °C. The thin films were deposited on yttria stabilized zirconia substrates (YSZ), operated as an electrochemical oxygen pump, to periodically adjust the oxygen activity in the films, leading to reversible expansion and contraction of the film. This further leads to stresses in the underlying YSZ substrates, accompanied by bending of the overall devices. Film thickness changes and sample bending are found to reach up to 10 and several hundred nanometers, respectively, at excitation frequencies from 0.1 to 10 Hz and applied voltages from 0–0.75 V for PCO and 0–1 V for ceria. At low frequencies, equilibrium conditions are approached. As a consequence maximum thin-film expansion of PCO is expected due to full reduction of the Pr ions. The lower detection limit for displacements is found to be in the subnanometer range. At 800 °C and an excitation frequency of 1 Hz, the LDV shows a remarkable resolution of 0.3 nm which allows, for example, the characterization of materials with small levels of expansion, such as undoped ceria at high oxygen partial pressure. As the correlation between film expansion and sample bending is obtained through this study, a dimensional change of a free body consisting of the same material can be calculated using the high resolution characteristics of this system. A minimum detectable dimensional change of 5 pm is estimated even under challenging high-temperature conditions at 800 °C opening up opportunities to investigate electro-chemo-mechanical phenomena heretofore impossible to investigate. The expansion data are correlated with previous results on the oxygen nonstoichiometry of PCO thin films, and a defect model for bulk ceria solid solutions is adopted to calculate the cation and anion radii changes in the constrained films during chemical expansion. The constrained films exhibit anisotropic volume expansion with displacements perpendicular to the substrate plane nearly double that of bulk samples. The PCO films used here generate high total displacements of several 100 nm’s with high reproducibility. Consequently, PCO films are identified to be a potential core component of high-temperature actuators. They benefit not only from high displacements at temperatures where most piezoelectric materials no longer operate while exhibiting, low voltage operation and low energy consumption.

scholarly journals The Effects of Surfactant on the Evolution of a Thin Film under a Moving Liquid Drop

2020 ◽  
Vol 5 (1) ◽  
pp. 75-85
Author(s):  
Kartika Yulianti ◽  
Agus Yodi Gunawan ◽  
Edy Soewono
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Solid Surface ◽  
Surfactant Concentration ◽  
Liquid Drop ◽  
Nonlinear Partial Differential Equations ◽  
Normal Pressure ◽  
Lubrication Approximation ◽  
Moving Liquid

The effect of surfactant on the thickness of a thin film bounded by a solid surface and a moving liquid drop was investigated. We proposed a model so that parameters from the liquid drop can be stated in a parameter that acts as normal pressure to the thin film. Using the lubrication approximation, the model was reduced to a set of nonlinear partial differential equations in terms of the film thickness and surfactant concentration. Since we were interested in the role of the surfactant in lifting up the drop, we assumed that the density of the drop is higher than the density of the thin film. Numerically, the results show that the presence of the surfactant tends to delay the decrease of the film thickness insignificantly. However, when the surfactant was added into the system, it tends to significantly increase the film thickness for a certain range value of the normal pressure.

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