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TRANSPARENT

ELECTRONICSBy…

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Ever you wondered that you are travelling in a car and you want to watch a movie or play video 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…!!!

It is possible with the help of transparent electronics.

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TRANSPARENT WASHER

Content-»Introduction

»Pre-History

»How Transparent electronic devices work?

»Advancement made in transparent electronics

»Application

»Market

»Future scope

»Conclusion

»References

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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.

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PRE-HISTORYThe 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.

MaterialBandgap

(eV)

Conductivity(Scm-1)

(siemen/cm)

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

Electrical properties of common TCOs

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Transparent conductive oxides Transparent conductive oxides (TCO) are doped metal oxides used in optoelectronic

devices such as flat panel displays and photovoltaic. Most of these films are fabricated

with polycrystalline or amorphous microstructures.

Thin-film transistor (TFT)A thin-film transistor (TFT) is a special kind of field-effect transistor made by

depositing thin films  of an active semiconductor layer as well as the dielectric layer

and metallic contacts over a supporting (but non-conducting) substrate. A common

substrate is glass , because the primary application of TFTs is in liquid-crystal displays. 

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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).

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.

A comparison of ZnO and a-IGZO(indium gallium zinc oxide)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 low-temperature processing, etc.

Oxides play key role:Oxides

ZnO InGaZnO4

The major substrate used for this purpose is Glass. Diamo

nd

Glass

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ADVANCEMENTS MADE IN TRANSPARENT

ELECTRONICS

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 begin.

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.

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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…

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 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 coatings2. Touch display panels3. Solar cells,4. Flat panel displays5. Heaters6. Defrosters7. Optical coatings. and many more….

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MARKET OF TRANSPARENT ELECTRONICS

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:• Integration• Improved economics• Aspects of transparent materials that are not directly related to transparency.

The transparent electronic devices in the market have many challenges to overcome in order to capture the market like current apps for transparent electronics are quite primitive.This is the major distraction in the path of these invisible devices…!!!

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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.

# SOLAR AND PV CELLS

# TOUCH SURFACES

# MAINSTREAM DISPLAYS

# UNCONVENTIONAL SURFACES

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CONCLUSION Oxides represent a relatively new class of

semiconductor materials applied to active devices, such as TFTs.

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.

REFERENCES www.wikipedia.org www.ieee.org www.sciencemag.org  www.nanomarket.net

www.esciencenews.com 

Thank you

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