The researchers, Shinya Aikawa and coauthors from the University of
Tokyo and the Tokyo University of Science, have published their study in
a recent issue of Applied Physics Letters.
“The most important thing is that electronics might now be usable in
places or situations that were previously not possible,” coauthor Shigeo
Maruyama, a mechanical engineering professor at the University of
Tokyo, told PhysOrg.com. “Since our device is so flexible and
deformable it could potentially be stuck anywhere. This could lead to
active electronic devices that are applied like a sticker or an adhesive
bandage, as well as to wearable electronics.”
Unlike other field-effect transistors
(FETs), the new FET is unique in that all channels and electrodes are
made of carbon nanotubes (CNTs), while the substrate is made of highly
flexible and transparent poly(vinyl alcohol) (PVA). Previously, the
majority of flexible, transparent FETs have used gold or indium tin
oxide as electrodes. However, gold decreases the devices’ transparency
while brittle indium tin oxide limits the flexibility. A few recent FETs
have been made that consist entirely of CNTs, but so far these devices
have been built on thick plastic substrates, limiting their flexibility.
The present device (1 mm curvature) is the most bendable CNT-FET to date
without performance degradation. Image credit: Aikawa, et al. ©2012
American Institute of Physics
After patterning the components using standard photolithography and
laminating the device with the PVA, the final thickness of the new
all-CNT-FET was approximately 15 µm. This thinness made the device
highly pliable, with tests showing that the finished transistor could
withstand a 1-mm bending radius with almost no changes in electrical properties.
Although other transistors have been developed with bendable radii as
low as 0.1 mm, the new transistor is the most bendable that experiences
no performance degradation.
After subjecting the transistor to 100 wrinkling cycles, the
researchers observed a slight decrease in maximum drain current, which
may be due to some broken connections in the CNT network. However, the
minimal decrease in maximum drain current, which stabilizes after about
30 cycles, does not affect the overall transconductance, which was not
affected by the repeated bending.
In addition to its flexibility, the all-CNT-FET also has an optical
transmittance of more than 80%, which is sufficient to clearly see
through the device. The researchers attribute the high flexibility to
the inherent robustness of carbon nanotubes, and predict that they could
increase the flexibility even further by optimizing the positions of
the channels. Overall, the results demonstrate that flexible,
transparent all-carbon electronics are coming closer to commercial
reality.
“Ongoing topics are to control device properties and to integrate
them,” Maruyama said. “If these issues can be resolved, we would like to
realize flexible and transparent all-carbon working circuits.”
From physorg
1 comments:
Thank you for sharing the information.Thsi will help me i preparing the ppt on carbon nanotube :)
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