Delamination-Based Measurement and Prediction of the Adhesion Energy of Thin Film/Substrate Interfaces

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Liangliang Zhu ◽  
Xi Chen
Keyword(s):  
Thin Film ◽  
Flexible Electronics ◽  
Current Method ◽  
Adhesion Energy ◽  
Two Dimensional ◽  
Soft Substrate ◽  
Interface Adhesion ◽  
Compliant Substrates ◽  
And Performance ◽  
Film Substrate

With the rapid emerging of two-dimensional (2D) micro/nanomaterials and their applications in flexible electronics and microfabrication, adhesion between thin film and varying substrates is of great significance for fabrication and performance of micro devices and for the understanding of the buckle delamination mechanics. However, the adhesion energy remains to be difficult to be measured, especially for compliant substrates. We propose a simple methodology to deduce the adhesion energy between a thin film and soft substrate based on the successive or simultaneous emergence of wrinkles and delamination. The new metrology does not explicitly require the knowledge of the Young's modulus, Poisson's ratio, and thickness of the 2D material, the accurate measurement of which could be a challenge in many cases. Therefore, the uncertainty of the results of the current method is notably reduced. Besides, for cases where the delamination width is close to the critical wrinkle wavelength of the thin film/substrate system, the procedure can be further simplified. The simple and experimentally easy methodology developed here is promising for determining/estimating the interface adhesion energy of a variety of thin film/soft substrate systems.

scholarly journals Sequential Oxidation Strategy for the Fabrication of Liquid Metal Electrothermal Thin Film with Desired Printing and Functional Property

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1539
Author(s):  
Jun-Heng Fu ◽  
Xu-Dong Zhang ◽  
Peng Qin ◽  
Jing Liu
Keyword(s):  
Thin Film ◽  
Liquid Metal ◽  
Composite Film ◽  
Flexible Electronics ◽  
High Performance ◽  
Polyimide Film ◽  
Great Promise ◽  
Metal Composite ◽  
Resistive Layer ◽  
Film Substrate

Room temperature liquid metal (LM) showcases a great promise in the fields of flexible functional thin film due to its favorable characteristics of flexibility, inherent conductivity, and printability. Current fabrication strategies of liquid metal film are substrate structure specific and sustain from unanticipated smearing effects. Herein, this paper reported a facile fabrication of liquid metal composite film via sequentially regulating oxidation to change the adhesion characteristics, targeting the ability of electrical connection and electrothermal conversion. The composite film was then made of the electrically resistive layer (oxidizing liquid metal) and the insulating Polyimide film (PI film) substrate, which has the advantages of electrical insulation and ultra-wide temperature working range, and its thickness is only 50 μm. The electrical resistance of composite film can maintain constant for 6 h and could work normally. Additionally, the heating film exhibited excellent thermal switching characteristics that can reach temperature equilibrium within 100 s, and recovery to ambient temperature within 50 s. The maximum working temperature of the as-prepared film is 115 °C, which is consistent with the result of the theoretical calculation, demonstrating a good electrothermal conversion capability. Finally, the heating application under extreme low temperature (−196 °C) was achieved. This conceptual study showed the promising value of the prototype strategy to the specific application areas such as the field of smart homes, flexible electronics, wearable thermal management, and high-performance heating systems.

A new paradigm in thin film indentation

2010 ◽  
Vol 25 (9) ◽  
pp. 1671-1678 ◽  
Author(s):  
Bo Zhou ◽  
Barton C. Prorok
Keyword(s):  
Thin Film ◽  
Transfer Model ◽  
New Paradigm ◽  
Compliant Substrates ◽  
Wide Range ◽  
Stiffness Method ◽  
Elastic Interface ◽  
Film Substrate ◽  
Influence Behavior ◽  
Membrane Deflection

A new method to accurately and reliably extract the actual Young's modulus of a thin film on a substrate by indentation was developed. The method involved modifying the discontinuous elastic interface transfer model to account for substrate effects that were found to influence behavior a few nanometers into a film several hundred nanometers thick. The method was shown to work exceptionally well for all 25 different combinations of five films on five substrates that encompassed a wide range of compliant films on stiff substrates to stiff films on compliant substrates. A predictive formula was determined that enables the film modulus to be calculated as long as one knows the film thickness, substrate modulus, and bulk Poisson's ratio of the film and the substrate. The calculated values of the film modulus were verified with prior results that used the membrane deflection experiment and resonance-based methods. The greatest advantages of the method are that the standard Oliver and Pharr analysis can be used, and that it does not require the continuous stiffness method, enabling any indenter to be used. The film modulus then can be accurately determined by simply averaging a handful of indents on a film/substrate composite.

Directly deposited MoS2thin film electrodes for high performance supercapacitors

2015 ◽  
Vol 3 (47) ◽  
pp. 24049-24054 ◽  
Author(s):  
Nitin Choudhary ◽  
Mumukshu Patel ◽  
Yee-Hsien Ho ◽  
Narendra B. Dahotre ◽  
Wonki Lee ◽  
...  
Keyword(s):  
Thin Film ◽  
Flexible Electronics ◽  
High Performance ◽  
Cyclic Stability ◽  
Two Dimensional ◽  
Polymer Substrates ◽  
Energy Devices ◽  
Direct Deposition ◽  
Cu Foil

We demonstrate the direct deposition of two-dimensional (2D) MoS2thin film on Cu-foil and polymer substrates, exhibiting an excellent capacitance and outstanding cyclic stability. The MoS2based supercapacitors will enable new opportunities in flexible electronics and energy devices.

A General Solution for Two-Dimensional Stress Distributions in Thin Films

2004 ◽  
Vol 71 (5) ◽  
pp. 691-696 ◽  
Author(s):  
R. Krishnamurthy ◽  
D. J. Srolovitz
Keyword(s):  
Thin Film ◽  
Fourier Coefficients ◽  
Fourier Transforms ◽  
Fourier Integral ◽  
Two Dimensional ◽  
Stress Distributions ◽  
Closed Form Solutions ◽  
Thick Substrate ◽  
Film Substrate ◽  
Free Strain

We present closed-form solutions for stresses in a thin film resulting from a purely dilatational stress-free strain that can vary arbitrarily within the film. The solutions are specific to a two-dimensional thin film on a thick substrate geometry and are presented for both a welded and a perfectly slipping film/substrate interface. Variation of the stress-free strain through the thickness of the film is considered to be either arbitrary or represented by a Fourier integral, and solutions are presented in the form of a Fourier series in the lateral dimension x. The Fourier coefficients can be calculated rapidly using Fast Fourier Transforms. The method is applied to determine the stresses in the film and substrate for three cases: (a) where the stress-free strain is a sinusoidal modulation in x, (b) where the stress-free strain varies only through the thickness, and (c) where a rectangular inclusion is embedded within the film, and the calculated stresses match accurately with the exact solutions for these cases.

Quantitative characterization of interface stress using a nanoindentation technique for high performance flexible electronics

2020 ◽  
Vol 8 (35) ◽  
pp. 12155-12163
Author(s):  
Xiumei Wang ◽  
Guocheng Zhang ◽  
Huihuang Yang ◽  
Yaqian Liu ◽  
Shaomin Chen ◽  
...  
Keyword(s):  
Flexible Electronics ◽  
Formation Process ◽  
High Performance ◽  
Film Formation ◽  
Adhesion Energy ◽  
Interface Stress ◽  
Quantitative Characterization ◽  
Interface Adhesion ◽  
Simple Method

A simple method was introduced to precisely characterize the interface stress of flexible OFETs using nanoindentation. The interface stress could be tuned by controlling the interface adhesion energy between layers, via controlling the film formation process.

a-Si TFTs on Thin Steel Foil Substrates: How Thin Can We Go?

1999 ◽  
Vol 558 ◽  
Author(s):  
Eugene Ma ◽  
Sigurd Wagner
Keyword(s):  
Thin Film ◽  
Mechanical Stress ◽  
Performance Metrics ◽  
Thin Steel ◽  
And Performance ◽  
Film Substrate

ABSTRACTThe mechanics of thin film-substrate couples indicates that mechanical stress in the active electronic layer can be reduced when films are deposited onto thinner substrates. To explore the question of just how thin a substrate can be, a-Si:H TFTs are fabricated on thin steel foil substrates of various thickness, and performance metrics from devices on each of the substrates are measured and compared.

Microtomy of spherical Al2O3 powders

1983 ◽  
Vol 41 ◽  
pp. 74-75
Author(s):  
E.J. Jenkins ◽  
D.S. Tucker ◽  
J.J. Hren
Keyword(s):  
Thin Film ◽  
Size Range ◽  
Particle Aggregation ◽  
Ion Milling ◽  
Thin Sections ◽  
Α Phase ◽  
Convenient Means ◽  
Van Der Waals Attraction ◽  
Negative Feature ◽  
Film Substrate

The size range of mineral and ceramic particles of one to a few microns is awkward to prepare for examination by TEM. Electrons can be transmitted through smaller particles directly and larger particles can be thinned by crushing and dispersion onto a substrate or by embedding in a film followed by ion milling. Attempts at dispersion onto a thin film substrate often result in particle aggregation by van der Waals attraction. In the present work we studied 1-10 μm diameter Al2O3 spheres which were transformed from the amprphous state to the stable α phase.After the appropriate heat treatment, the spherical powders were embedded in as high a density as practicable in a hard EPON, and then microtomed into thin sections. There are several advantages to this method. Obviously, this is a rapid and convenient means to study the microstructure of serial slices. EDS, ELS, and diffraction studies are also considerably more informative. Furthermore, confidence in sampling reliability is considerably enhanced. The major negative feature is some distortion of the microstructure inherent to the microtoming operation; however, this appears to have been surprisingly small. The details of the method and some typical results follow.

Microstructural investigation of surface roughness in MBE-grown AlAs

1995 ◽  
Vol 53 ◽  
pp. 454-455
Author(s):  
R. Rajesh ◽  
R. Droopad ◽  
C. H. Kuo ◽  
R. W. Carpenter ◽  
G. N. Maracas
Keyword(s):  
Thin Film ◽  
Real Time ◽  
Growth Control ◽  
Native Oxide ◽  
Effusion Cell ◽  
Surface Oxide Layer ◽  
Microstructural Investigation ◽  
Mbe Growth ◽  
Film Substrate ◽  
And Control

Knowledge of material pseudodielectric functions at MBE growth temperatures is essential for achieving in-situ, real time growth control. This allows us to accurately monitor and control thicknesses of the layers during growth. Undesired effusion cell temperature fluctuations during growth can thus be compensated for in real-time by spectroscopic ellipsometry. The accuracy in determining pseudodielectric functions is increased if one does not require applying a structure model to correct for the presence of an unknown surface layer such as a native oxide. Performing these measurements in an MBE reactor on as-grown material gives us this advantage. Thus, a simple three phase model (vacuum/thin film/substrate) can be used to obtain thin film data without uncertainties arising from a surface oxide layer of unknown composition and temperature dependence.In this study, we obtain the pseudodielectric functions of MBE-grown AlAs from growth temperature (650°C) to room temperature (30°C). The profile of the wavelength-dependent function from the ellipsometry data indicated a rough surface after growth of 0.5 μm of AlAs at a substrate temperature of 600°C, which is typical for MBE-growth of GaAs.

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