The document discusses transparent electronics, which uses wide bandgap semiconductors to create invisible circuits and optoelectronic devices. It describes how transparent oxide semiconductors like indium oxide, tin oxide, and zinc oxide combine high conductivity with high visual transparency. Transparent thin-film transistors and recent advances in "p-type" semiconductors are enabling new types of electronic circuits that can be deposited on glass and are literally invisible. Potential applications of transparent electronics include see-through displays, touchscreens, solar cells, and heaters. Continued research aims to improve performance and fabrication techniques to bring this emerging technology into more widespread use.

1. PRESENTED BY :-
ASHISH RANJAN
1

2. 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 opto-electronic
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.

3. PRE-HISTORY
Material
Bandgap
(eV)
Conductivity
(Scm-1)
Electron
Concentration
(cm-3)
Mobility
(cm2V-1s-1)
In2O3 3.75 10,000 >1021 35
ZnO2 3.35 8,000 >1021 20
SnO2 3.6 5,000 >1020 15
Table 1: Electrical properties of common TCOs
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.

4.  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.
Fig 1: Structure of TFTs

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).

6.  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 (a-IGZO) also used
in this application.
OXIDES PLAY KEY ROLE :
Oxides
ZnO InGaZnO4
Fig 2:- The major substrate used
for this purpose is Glass.
Diamond
Glass
Fig 3:-Graph showing variation
of transmittance and wavelength
of Substrate.

7.  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.
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.
Fig 4: Generation of Transparent Electronics

8. 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.
Lets consider the properties of materials other
than transparency and their applications…

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….

10. 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.

11. 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…!!!

12. REFERENCES
1. ‘Transparent Electronics ’, Springer publications,
J.F.Wager, D. A. Keszler, R. E. Presley.
2. ‘Transparent electronics: from synthesis to applications’,
Wiley publications: Antonio Facchetti, Tobin J. Marks.
3. www.alternative-energy-news.info/transparent-a-solar-
energy-breakthrough/
4. www.nanomarkets.net
5. www.nikkeibp.co.jp

13. That’s all about Transparent Electronics…!!!
Thank you and queries…!!!