15-10-2016, 04:14 PM
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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!!!
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.
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.
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).
Oxides play key role:
The main advantages of using ZnO are:
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.
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 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.
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.
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!!!
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.
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.
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).
Oxides play key role:
The main advantages of using ZnO are:
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.
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 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.
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.