Surface morphology characterization of pentacene thin film and its substrate with under-layers by power spectral density using fast Fourier transform algorithms

Itoh, Taketsugu; Yamauchi, Noriyoshi

doi:10.1016/j.apsusc.2007.01.056

Cited by 57 publications

(41 citation statements)

References 20 publications

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“…As introduced in the last section of Computational methods and plotted in Figure 2b, the initial C(q) has been determined based on measured RMS roughness for the thin film type and bulk-type and relationship between C(q) and RMS discussed by Flys et al 47 After cycling, experimental studies 54,56,58,63 have reported the RMS roughness would increase. Also, based on the study of surface morphology, 45,46,64 the absolute value of m, of the plot in Figure 2b would increase, and the intercept, I, would be decreased when the RMS roughness is increased. (m, I) values were changed to mimic the effect interface roughening due to battery cycling.…”

Section: Resultsmentioning

confidence: 99%

“…For example, an interface may look like contact perfectly with uniform contact pressure at a macroscopic view, but at a microscopic view, the surface roughness will lead to non-perfect contact and non-uniform contact stress. By assuming that surface roughness has self-affined property, [45][46][47][48] this model can calculate the real contact area at every length scale. Thus, it is important to define the length scales for the battery systems.…”

Section: After LImentioning

confidence: 99%

“…The different length scale is described by wavenumbers, and the surface power spectrum density will have an exponential relationship with the wavenumber, proving the self-affine property. [45][46][47][48] Therefore, Persson's contact mechanics theory, 49 which models the contact area variation from 0% to 100% as a function of applied pressure on interfaces with the multi-scale self-affine property, will be adopted for the current model.…”

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confidence: 99%

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Simulation of the Effect of Contact Area Loss in All-Solid-State Li-Ion Batteries

Tian

2017

J. Electrochem. Soc.

121

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Maintaining the physical contact between the solid electrolyte and the electrode is important to improve the performance of all-solidstate batteries. Imperfect contact can be formed during cell fabrication and will be worsened due to cycling, resulting in degradation of the battery performance. In this paper, the effect of imperfect contact area was incorporated into a 1-D Newman battery model by assuming the current and Li concentration will be localized at the contacted area. Constant current discharging processes at different rates and contact areas were simulated for a film-type Li|LiPON|LiCoO 2 all-solid-state Li-ion battery. The capacity drop was correlated with the contact area loss. It was found at lower cutoff voltage, the correlation is almost linear with a slope of 1; while at a higher cutoff voltage, the dropping rate is slower. To establish the relationship between the applied pressure and the contact area, Persson's contact mechanics theory was applied, as it uses self-affined surfaces to simplify the multi-length scale contacts in all-solid-state batteries. The contact area and pressure were computed for both film-type and bulk-type all-solid-state Li-ion batteries. The model is then used to suggest how much pressures should be applied to recover the capacity drop due to contact area loss. Conventional Li-ion batteries usually include a liquid electrolyte, which facilitates Li-ions transport between cathode and anode. However, the applications of Li-ion batteries are still limited by the flammability and narrow electrochemical window of the liquid electrolytes. 1-3During the past decades, several solid electrolytes 4-9 with the ionic conductivity close to the liquid electrolyte have been developed, thus enabled the development of all-solid-state batteries. The benefits of all-solid-state batteries are high energy density, non-flammability, and the large electrochemical window (if the solid electrolyte form stable interphase layers on electrode surface). 10,11However, a major bottleneck for all-solid-state Li-ion batteries lies at the high interfacial resistance due to two main factors, chemical effect and physical contact. 3 The chemical effect refers to the chemical changes at the solid-electrolyte/electrode interface that cause slower transport. The chemical changes include the interphase layer formation due to solid electrolyte decomposition, 11 and/or Li-ion depletion zone at the interface 12 (for example, LiPON/Li 2 CO 3 ). Physical contact induced impedance comes from the imperfect contact at the solid-electrolyte/electrode interface, which plays a more important role for batteries using solid-electrolytes than the conventional batteries employing liquid electrolytes. Liquid electrolytes can easily diffuse through the porous electrode and wet the electrode surface, so, any fracture and disconnection between solid particles will only cause electrical disconnection. However, for solid electrolytes, the fracture and disconnection will impede Li-ion transport, as well as electron transport. Thus...

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Section: Resultsmentioning

confidence: 99%

Section: After LImentioning

confidence: 99%

mentioning

confidence: 99%

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Simulation of the Effect of Contact Area Loss in All-Solid-State Li-Ion Batteries

Tian

2017

J. Electrochem. Soc.

121

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“…The unit of 1D-PSD is in (length) 3 . In the case 2D-PSD the mathematical equation can be written as [10]:…”

Section: Power Spectral Densitymentioning

confidence: 99%

Morphology Evolution Of ZnO Thin Films Deposited By Nitrogen Mediated Crystallization Method

Suhariadi

Shiratani

Itagaki

2018

MATEC Web of Conferences

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Abstract.We study the surface morphology of ZnO thin films deposited by nitrogen mediated crystallization method utilizing atomic force microscopy as a function of nitrogen flow rates. Initially, the surface morphology of ZnO thin film deposited without nitrogen exhibits a bumpy surface with spiky grains where the skewness and kurtosis values were found to be 0.48 and 4.80, respectively. By addition of small amount of nitrogen, the skewness and kurtosis values of the films significantly decrease associated with a flatter topography. Further increase in nitrogen flow rate to 16 sccm has roughened the surface shown mainly by the increase in kurtosis value to be 3.30. These results indicate that the addition of small amount of nitrogen during deposition process has enhanced the adatoms migration on the surface resulting in a superior film with a larger grain size. Two-dimensional power spectral density analysis reveals that all the films have self-affine fractal geometry with total fractal values in the range of 2.14 to above 3.00.

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“…(1) should be replaced by\h[since they talk about the mean height [2]. Besides, in page 3, line 5, DL = N/L can not dimensionally be correct relation and the proper Equation is DL = L/N [3] and more, as can be seen in [4] the correct form of Eq. 5 is D f ¼ 4 þ c=2.…”

mentioning

confidence: 99%

Comment on: “Characterization of Microroughness Parameters in Titanium Nitride Thin Films Grown by DC Magnetron Sputtering” [J Fusion Energ DOI 10.1007/s10894-012-9510-z]

2012

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In recent article [Ali Gelali. Azin Ahmadpourian. Reza Bavadi. M. R. Hantehzadeh. Arman Ahmadpourian. J Fusion Energ DOI 10.1007/s10894-012-9510-z], Ali Geleli et al. studied the PSD and RMS Roughness parameters in Titanium Nitride thin films by AFM data and used the computed fractal dimension value of micrographs to describe the surface morphology of thin films. Here, the correct form of equations and relationship between PSD and RMS will be discussed.

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Surface morphology characterization of pentacene thin film and its substrate with under-layers by power spectral density using fast Fourier transform algorithms

Cited by 57 publications

References 20 publications

Simulation of the Effect of Contact Area Loss in All-Solid-State Li-Ion Batteries

Simulation of the Effect of Contact Area Loss in All-Solid-State Li-Ion Batteries

Morphology Evolution Of ZnO Thin Films Deposited By Nitrogen Mediated Crystallization Method

Comment on: “Characterization of Microroughness Parameters in Titanium Nitride Thin Films Grown by DC Magnetron Sputtering” [J Fusion Energ DOI 10.1007/s10894-012-9510-z]

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