Interconnects for Elastically Stretchable and Deformable Electronic Surfaces

AbstractDeformable, large-area electronic surfaces are desirable for many human-machine interfaces. The goal of our research is to fabricate elastically deformable electronics by integrating electronic devices and stretchable interconnects onto a flexible substrate. The focus of this paper is the fabrication and electrical performance of the stretchable interconnects. Au was deposited onto a silicone elastomer (PDMS) and patterned to achieve a resolution of 2 μm. Two patterning techniques are presented: patterning by shadow mask and patterning by photolithography. Photolithographic patterning on PDMS is not straightforward. First, we discuss the challenges in patterning and then the morphology of lines patterned by both techniques. The electrical resistance of the Au lines under tensile strain is presented. Interconnects patterned by shadow mask remain electrically conductive up to 100 % strain. Those patterned by photolithography maintain electrical conductivity when strained up to 60 %.

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Stretchable Dielectric Material for Conformable Bioelectronic Devices

MRS Proceedings ◽

10.1557/proc-0926-cc02-02 ◽

2006 ◽

Vol 926 ◽

Cited By ~ 1

Author(s):

Candice Tsay ◽

Stephanie P. Lacour ◽

Sigurd Wagner ◽

Zhe Yu ◽

Barclay Morrison

Keyword(s):

Mechanical Stress ◽

Tensile Strain ◽

Dielectric Material ◽

Electronic Devices ◽

Hippocampal Slices ◽

Dielectric Strength ◽

Electrical Performance ◽

Living Tissue ◽

Silicone Polymer

ABSTRACTWe use a photo-patternable silicone polymer to fabricate an elastically deformable encapsulation film on stretchable gold lines that electrically conduct while stretched to >50% strain. To detect bioelectrical signals, these stretchable gold lines are patterned as leads and micro-electrodes. They need to be encapsulated with a material that is electrically insulating, as stretchable as the elastomeric substrate, and that can be readily patterned to define recording sites. First, we evaluate the biocompatibility of the elastic encapsulation polymer by assessing the viability of the organotypic hippocampal slices cultured on it. Then, to test the electrical performance of the encapsulation film under large mechanical stress, we measure the dielectric strength of the encapsulation film to 50% tensile strain. Our findings indicate that the photo-patternable silicone material is a suitable interface toin vitroliving tissue, and is a reliable stretchable insulator for soft and conformable electronic devices.

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Electrical Failure and Damage Analysis of Multi-Layer Metal Films on Flexible Substrate during Cyclic Bending Deformation

ISTFA 2011: Conference Proceedings from the 37th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2011p0001 ◽

2011 ◽

Author(s):

Byoung-Joon Kim ◽

Hae-A-Seul Shin ◽

In-Suk Choi ◽

Young-Chang Joo

Keyword(s):

Fatigue Resistance ◽

Electrical Resistance ◽

Metal Film ◽

Flexible Substrate ◽

Resistance Change ◽

Cyclic Bending ◽

Capping Layer ◽

Bending Strain ◽

Cu Film ◽

Electrical Resistance Change

Abstract The electrical resistance Cu film on flexible substrate was investigated in cyclic bending deformation. The electrical resistance of 1 µm thick Cu film on flexible substrate increased up to 120 % after 500,000 cycles in 1.1 % tensile bending strain. Crack and extrusion were observed due to the fatigue damage of metal film. Low bending strain did not cause any damage on metal film but higher bending strain resulted in severe electrical and mechanical damage. Thinner film showed higher fatigue resistance because of the better mechanical property of thin film. Cu film with NiCr under-layer showed poorer fatigue resistance in tensile bending mode. Ni capping layer did not improve the fatigue resistance of Cu film, but Al capping layer suppressed crack formation and lowered electrical resistance change. The NiCr under layer, Ni capping layer, and Al capping layer effect on electrical resistance change of Cu film was compared with Cu only sample.

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Nanonet: Low-temperature-processed tellurium nanowire network for scalable p-type field-effect transistors and a highly sensitive phototransistor array

NPG Asia Materials ◽

10.1038/s41427-021-00314-y ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Muhammad Naqi ◽

Kyung Hwan Choi ◽

Hocheon Yoo ◽

Sudong Chae ◽

Bum Jun Kim ◽

...

Keyword(s):

Low Temperature ◽

Field Effect ◽

High Performance ◽

Field Effect Transistors ◽

Optical Measurements ◽

Electrical Performance ◽

Large Area ◽

Nanowire Network ◽

P Type ◽

Nanowire Networks

AbstractLow-temperature-processed semiconductors are an emerging need for next-generation scalable electronics, and these semiconductors need to feature large-area fabrication, solution processability, high electrical performance, and wide spectral optical absorption properties. Although various strategies of low-temperature-processed n-type semiconductors have been achieved, the development of high-performance p-type semiconductors at low temperature is still limited. Here, we report a unique low-temperature-processed method to synthesize tellurium nanowire networks (Te-nanonets) over a scalable area for the fabrication of high-performance large-area p-type field-effect transistors (FETs) with uniform and stable electrical and optical properties. Maximum mobility of 4.7 cm2/Vs, an on/off current ratio of 1 × 104, and a maximum transconductance of 2.18 µS are achieved. To further demonstrate the applicability of the proposed semiconductor, the electrical performance of a Te-nanonet-based transistor array of 42 devices is also measured, revealing stable and uniform results. Finally, to broaden the applicability of p-type Te-nanonet-based FETs, optical measurements are demonstrated over a wide spectral range, revealing an exceptionally uniform optical performance.

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Effect of Applied Pressure on the Electrical Resistance of Carbon Nanotube Fibers

Materials ◽

10.3390/ma14092106 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2106

Author(s):

Chris J. Barnett ◽

James D. McGettrick ◽

Varun Shenoy Gangoli ◽

Ewa Kazimierska ◽

Alvin Orbaek White ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Electrical Resistance ◽

Copper Wire ◽

Applied Pressure ◽

Radial Strain ◽

Electrical Current ◽

Electrical Contacts ◽

Electrical Performance ◽

Macro Scale ◽

Carbon Nanotube Fibers

Carbon nanotubes (CNTs) can be spun into fibers as potential lightweight replacements for copper in electrical current transmission since lightweight CNT fibers weigh <1/6th that of an equivalently dimensioned copper wire. Experimentally, it has been shown that the electrical resistance of CNT fibers increases with longitudinal strain; however, although fibers may be under radial strain when they are compressed during crimping at contacts for use in electrical current transport, there has been no study of this relationship. Herein, we apply radial stress at the contact to a CNT fiber on both the nano- and macro-scale and measure the changes in fiber and contact resistance. We observed an increase in resistance with increasing pressure on the nanoscale as well as initially on the macro scale, which we attribute to the decreasing of axial CNT…CNT contacts. On the macro scale, the resistance then decreases with increased pressure, which we attribute to improved radial contact due to the closing of voids within the fiber bundle. X-ray photoelectron spectroscopy (XPS) and UV photoelectron spectroscopy (UPS) show that applied pressure on the fiber can damage the π–π bonding, which could also contribute to the increased resistance. As such, care must be taken when applying radial strain on CNT fibers in applications, including crimping for electrical contacts, lest they operate in an unfavorable regime with worse electrical performance.

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Mechanical and Electrical Performance of Flexible Polymer Film Designed for a Textile Electrically-Conductive Path

Materials ◽

10.3390/ma14092169 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2169

Author(s):

Agnieszka Tabaczyńska ◽

Anna Dąbrowska ◽

Marcin Masłowski ◽

Anna Strąkowska

Keyword(s):

Ionic Liquid ◽

Ionic Liquids ◽

Surface Resistance ◽

Conductive Filler ◽

Extrusion Process ◽

Electrical Performance ◽

Electrically Conductive ◽

Non Invasive ◽

Flexible Polymer ◽

The Stability

Electro-conductive paths that are mechanically resistant and stable during simulated aging cycles are promising, in relation to the non-invasive application in e-textiles in our everyday surroundings. In the paper, an analysis of the influence of electro-conductive filler, as well as ionic liquid on surface resistance is provided. Authors proved that depending on the tested variant, obtained surface resistance may vary from 50 kΩ (when 50 phr of Ag and [bmim][PF6] ionic liquid applied) to 26 GΩ (when 25 phr of Ag and [bmim][PF6] ionic liquid applied). The samples were also evaluated after simulated aging cycles and the stability of electric properties was confirmed. Moreover, it was proved that the addition of ionic liquids reduced the resistance of vulcanizates, while no significant influence of the extrusion process on conductivity was observed.

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The Impact of Elongation on Change in Electrical Resistance of Electrically Conductive Yarns Woven into Fabric

Materials ◽

10.3390/ma14123390 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3390

Author(s):

Željko Knezić ◽

Željko Penava ◽

Diana Šimić Penava ◽

Dubravko Rogale

Keyword(s):

Mathematical Model ◽

Electrical Resistance ◽

Electrically Conductive ◽

Textile Materials ◽

Measurement Results ◽

Conductive Yarns ◽

Yarn Count ◽

As Relationship ◽

The Impact ◽

The Mathematical Model

Electrically conductive yarns (ECYs) are gaining increasing applications in woven textile materials, especially in woven sensors suitable for incorporation into clothing. In this paper, the effect of the yarn count of ECYs woven into fabric on values of electrical resistance is analyzed. We also observe how the direction of action of elongation force, considering the position of the woven ECY, effects the change in the electrical resistance of the electrically conductive fabric. The measurements were performed on nine different samples of fabric in a plain weave, into which were woven ECYs with three different yarn counts and three different directions. Relationship curves between values of elongation forces and elongation to break, as well as relationship curves between values of electrical resistance of fabrics with ECYs and elongation, were experimentally obtained. An analytical mathematical model was also established, and analysis was conducted, which determined the models of function of connection between force and elongation, and between electrical resistance and elongation. The connection between the measurement results and the mathematical model was confirmed. The connection between the mathematical model and the experimental results enables the design of ECY properties in woven materials, especially textile force and elongation sensors.

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Amorphous thin-film oxide power devices operating beyond bulk single-crystal silicon limit

Scientific Reports ◽

10.1038/s41598-021-88222-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yuki Tsuruma ◽

Emi Kawashima ◽

Yoshikazu Nagasaki ◽

Takashi Sekiya ◽

Gaku Imamura ◽

...

Keyword(s):

Thin Film ◽

Single Crystal ◽

Flexible Substrate ◽

Single Crystal Silicon ◽

Bulk Single Crystal ◽

Next Generation ◽

Power Devices ◽

Large Area ◽

Crystal Silicon ◽

Amorphous Thin Film

AbstractPower devices (PD) are ubiquitous elements of the modern electronics industry that must satisfy the rigorous and diverse demands for robust power conversion systems that are essential for emerging technologies including Internet of Things (IoT), mobile electronics, and wearable devices. However, conventional PDs based on “bulk” and “single-crystal” semiconductors require high temperature (> 1000 °C) fabrication processing and a thick (typically a few tens to 100 μm) drift layer, thereby preventing their applications to compact devices, where PDs must be fabricated on a heat sensitive and flexible substrate. Here we report next-generation PDs based on “thin-films” of “amorphous” oxide semiconductors with the performance exceeding the silicon limit (a theoretical limit for a PD based on bulk single-crystal silicon). The breakthrough was achieved by the creation of an ideal Schottky interface without Fermi-level pinning at the interface, resulting in low specific on-resistance Ron,sp (< 1 × 10–4 Ω cm2) and high breakdown voltage VBD (~ 100 V). To demonstrate the unprecedented capability of the amorphous thin-film oxide power devices (ATOPs), we successfully fabricated a prototype on a flexible polyimide film, which is not compatible with the fabrication process of bulk single-crystal devices. The ATOP will play a central role in the development of next generation advanced technologies where devices require large area fabrication on flexible substrates and three-dimensional integration.

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Protein Nanowires: the Electrification of the Microbial World and Maybe Our Own

Journal of Bacteriology ◽

10.1128/jb.00331-20 ◽

2020 ◽

Vol 202 (20) ◽

Cited By ~ 2

Author(s):

Derek R. Lovley ◽

Dawn E. Holmes

Keyword(s):

Electron Transport ◽

Long Range ◽

Electronic Devices ◽

Electricity Production ◽

Microbial World ◽

Electrically Conductive ◽

Anaerobic Digesters ◽

Content Type ◽

Type Iv ◽

Type Iv Pilin

ABSTRACT Electrically conductive protein nanowires appear to be widespread in the microbial world and are a revolutionary “green” material for the fabrication of electronic devices. Electrically conductive pili (e-pili) assembled from type IV pilin monomers have independently evolved multiple times in microbial history as have electrically conductive archaella (e-archaella) assembled from homologous archaellin monomers. A role for e-pili in long-range (micrometer) extracellular electron transport has been demonstrated in some microbes. The surprising finding of e-pili in syntrophic bacteria and the role of e-pili as conduits for direct interspecies electron transfer have necessitated a reassessment of routes for electron flux in important methanogenic environments, such as anaerobic digesters and terrestrial wetlands. Pilin monomers similar to those found in e-pili may also be a major building block of the conductive “cables” that transport electrons over centimeter distances through continuous filaments of cable bacteria consisting of a thousand cells or more. Protein nanowires harvested from microbes have many functional and sustainability advantages over traditional nanowire materials and have already yielded novel electronic devices for sustainable electricity production, neuromorphic memory, and sensing. e-pili can be mass produced with an Escherichia coli chassis, providing a ready source of material for electronics as well as for studies on the basic mechanisms for long-range electron transport along protein nanowires. Continued exploration is required to better understand the electrification of microbial communities with microbial nanowires and to expand the “green toolbox” of sustainable materials for wiring and powering the emerging “Internet of things.”

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