2. Ever wondered that you are travelling in
a car and you want to watch a movie or
video play and the glass shields i.e.
window panels will turn into a
television screen or working on a
computer that simply looks like a glass
sheet just like the future computer in
movie “Krrish” or holding a transparent
iPhone…!!!
Yeah you would have certainly…but
how is it possible!!!
That‟s what my topic “Transparent Electronics” is all about…!!!
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3. Introduction
Transparent electronics (also called as invisible
electronics) is an emerging technology.
It employs wide band-gap semiconductors for
the realization of invisible circuits and optoelectronic devices.
The first scientific goal of this technology must
be to discover, understand, and implement
transparent high-performance electronic materials.
The second goal is their implementation and
evaluation in transistor and circuit structures.
The third goal relates to achieving application-
specific properties since transistor performance and
materials property requirements vary, depending on
the final product device specifications.
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4. PRE-HISTORY
The two technologies which preceded and
underlie
transparent
electronics
are
Transparent Conductive Oxides (TCOs) and
Thin- Film Transistors (TFTs).
TCOs constitute an unusual class of
materials possessing two contradictory
physical properties- high optical transparency
and high electrical conductivity. The three
most common TCOs are indium oxide
In2O3, tin oxide SnO2 and zinc oxide ZnO2.
The thin-film transistor (TFTs) is another
technology
underlying
transparent
electronics, since it is a bridge between
passive electrical and active electronic
applications. But it does not evolve a fully
transparent transistor.
Electrical properties of common TCOs
Electron Mobil
Conducti
Concentr
ity
vity
ation (cm- (cm2V(Scm-1)
3)
1s-1)
Mate
rial
Band
gap
(eV)
In2O3
3.75
10,000
>1021
35
ZnO2
3.35
8,000
>1021
20
SnO2
3.6
5,000
>1020
15
Structure of TFTs
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5. HOW TRANSPARENT
ELECTRONIC DEVICES WORK?
The challenge for producing "invisible" electronic circuitry and opto-electronic
devices is that the transistor materials must be transparent to visible light yet have good
carrier mobilities which requires a special class of materials having "contra-indicated
properties".
Oxide semiconductors are very interesting materials because they combine
simultaneously high/low conductivity with high visual transparency.
Transparent oxide semiconductor based transistors have recently been proposed using
as active channel intrinsic zinc oxide (ZnO).
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6. Oxides play key role:
The main advantages of using ZnO are:
1. The fact that it is possible to growth at/near
room
temperature
high
quality
polycrystalline ZnO, which is a particular
advantage for electronic drivers, where the
response speed is of major importance.
2. Since ZnO is a wide band gap material (3.4
eV), it is transparent in the visible region of
the spectra and therefore, also less light
sensitive.
The second is amorphous oxides with heavy
metal content, such as amorphous InGaZnO4 (aIGZO) also used in this application.
A comparison of ZnO and a-IGZO shows that
ZnO has the lead when it comes to carrier
mobility. At present, though, a-IGZO is the
material
of
choice
for
large-area
displays, electronic paper utilizing lowtemperature processing, etc.
Oxides
ZnO
InGaZnO4
The major substrate used
for this purpose is Glass.
Diamond
Glass
7. ADVANCEMENTS MADE IN
TRANSPARENT ELECTRONICS
Significant advances in the emerging
science of transparent electronics, creating
transparent "p-type" semiconductors that
have more than 200 times the conductivity
of the best materials available for that
purpose a few years ago.
This basic research is opening the door to
new types of electronic circuits that, when
deposited onto glass, are literally invisible.
Researchers at Oregon State University and Hewlett Packard have reported
their first example of an entirely new class of materials which could be used to
make transparent transistors that are inexpensive, stable, and environmentally
benign.
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8. Lets consider the properties of materials other than
transparency and their applications…
Characteristics other than Transparency.
Transparent semiconductors, in addition to being transparent, have a number of useful
characteristics, including a wide band gap, relatively high carrier mobility, low-temperature
manufacturability, and low manufacturing costs thanks to the low-temperature process and
inexpensive materials. As a result, R&D into properties other than transparency is also active.
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9. APPLICATIONS OF
TRANSPARENT ELECTRONICS
Transparent
circuits
will
have
unprecedented applications in flat panel
displays and other electronic devices, such
as see through display or novel display
structures.
They have been widely used in a variety
of applications like:
1. Antistatic coatings
2. Touch display panels
3. Solar cells,
4. Flat panel displays
5. Heaters
6. Defrosters
7. Optical coatings.
and many more….
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10. MARKET OF TRANSPARENT
ELECTRONICS
The transparent electronic devices in the
market have two challenges to overcome in
order to capture the market. They are:
• Too cool to succeed
• Current apps for transparent electronics are
quite primitive.
These are the major distraction in the path of
these invisible devices…!!!
There are four critical aspects of “transparency” that the design and marketing of transparent
electronics products needs to focus on for it to become a serious revenue earner. These
factors are:
• Aesthetics
• Integration
• Improved economics
• Aspects of transparent materials that are not directly related to transparency.
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11. Future Scope
In the field of solar cells, although
much progress has been made in
developing new materials and
devices for high performance
transparent solar cells, there is still
plenty of opportunity to study and
improve device performance and
fabrication techniques compared with
the nontransparent solar cell devices.
It is likely that new scientific
discoveries
and
technological
advances will continue to cross
fertilize each other for the foreseeable
future.
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12. CONCLUSION
Oxides represent a relatively new class
of semiconductor materials applied to
active devices, such as TFTs, SWNT
transistors.
The combination of high field effect
mobility and low processing temperature
for oxide semiconductors makes them
attractive for high performance electronics
on flexible plastic substrates.
Let us hope that we are soon going to
see transparent technology being
implemented in our lives…!!!
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13. REFERENCES
„Transparent Electronics ‟, Springer
publications, J.F.Wager, D. A. Keszler, R. E.
Presley.
„Transparent electronics: from synthesis to
applications‟, Wiley publications: Antonio
Facchetti, Tobin J. Marks.
www.wikipedia.org
www.ieee.org
www.alternative-energy-news.info/transparenta-solar-energy-breakthrough/
www.nanomarkets.net
www.nikkeibp.co.jp
14. That’s all about Transparent
Electronics…!!!
Thank you and queries…!!!