kissthatfrog-1334938865249-phpapp01-120420112250-phpapp01 (1)
presentation1-120412032430-phpapp01 (1)
-
Upload
krunal-ramkar -
Category
Documents
-
view
222 -
download
0
Transcript of presentation1-120412032430-phpapp01 (1)
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
1/23
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
2/23
Capable of transmitting light so that objects or images can
be seen as if there were no intervening material
OR
An element so fine in texture that it can be seen through
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
3/23
The branch of physics that deals
with the emission and effects of
electrons and with the use of
electronic devices
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
4/23
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
5/23
Transparent electronics is anemerging technology that employs
wide band-gap semiconductors for
the realization of invisible circuits.
This monograph provides the first
roadmap for transparent electronics,
identifying where the field is, where
it is going, and what needs to
happen to move it forward.
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
6/23
Our motive is to create a technology that is
electrically conductive and with that it is
optically transparent.
Researchers at Oregon State University and
Hewlett Packard have reported their first
example of an entirely new class of materialswhich could be used to make transparent
transistors that are inexpensive, stable, and
environmentally benign.
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
7/23
Earth being the mother nature provides
us with resources that can conduct
electricallyAnd can be seen optically transparent
this means that the elements or
compoundsAbsorb all the colors in the given
spectrum and does not reflect any.
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
8/23
Efficient transparent conductors find their niche in a
compromise between a sufficient transmission
within the visible spectral range and a moderate butuseful in practice electrical conductivity. This
combination is achieved in several commonly used
oxides
In2O3, SnO2, ZnO and CdO. In the undopedstoichiometric state, these materials are insulators with
optical band gap of about 3 eV.
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
9/23
Transparent conductors are neither 100% optically
transparent nor metallically conductive. From the band
structure point of view, the combination of the two
properties in the same material is contradictory: a
transparent material is an insulator which possesses
completely filled valence and empty conduction bands;
whereas metallic conductivity appears when the Fermi
level lies within a band with a large density of states to
provide high carrier concentration.
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
10/23
The device building block materials, the semiconductor, the electric
contacts, and the dielectric/passivation layers, must now be transparent
in the visible a true challenge Therefore, 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.
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
11/23
During the past 10 years, the classes of materials
available for transparent electronics applications
have grown dramatically. Historically, this area
was dominated by transparent conducting oxides
(oxide materials that are both electrically
conductive and optically transparent) because of
their wide use in antistatic coatings, touch display
panels, solar cells, flat panel displays, heaters,
defrosters, smart windows and optical coatings.
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
12/23
The band structure point of view the combinationof
the two properties in the same material is
contradictory: a transparent material is an insulator
which possesses completely filled valence and empty
conduction bands; whereas metallic conductivity appears
when the Fermi level lies within a band with a large
density of states to provide high carrier concentration.
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
13/23
A transparent conducting oxide (TCO), these TCO hosts must
be degenerately doped to displace the Fermi level up into the
conduction band. The key attribute of any conventional n-type
TCO host is a highly dispersed single free electron- likeconduction band. Degenerate doping then provides both .
(i) the high mobility of extra carriers (electrons) due to their
small effective mass and
(ii) low optical absorption due to the low density of states inthe conduction band.
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
14/23
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
15/23
Passive linear
devices
TTFT
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
16/23
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
17/23
Transparent thin-film resistors TTFRs) are
expected to operate at relatively low
frequencies, so that parasitic inductance is
not anticipated to be relevant. Additionally,
TTFRs will most likely be fabricated on
insulating substrates, so that parasitic
capacitance should be minimal. Finally, if
properly designed, a TTFR is expected to
exhibit linear or very near-linear behavior.
Thus, in most respects, we expect a TTFR to be
adequately modeled as an ideal resistor.
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
18/23
The TTFC capacitance is established by the capacitance density
i.e. the capacitance per unit area of the basic capacitance stack
i.e.
S/dI and the geometric area of the capacitor layout.
Usually a large capacitance density is desired in order to minimize
the size of a capacitor. Therefore a thin insulator with a high
dielectric constant sometimes referred to as a high-k dielectric
,where k denotes the relative dielectric constant) is best.
However a high-k dielectric typically has a smaller band gap which
usually results in a low breakdown electric field
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
19/23
TTFIs will possess a significant amount
of parasitic resistance. Second
efficient magnetic field coupling is
strongly facilitated by the use of a
magnetically-permeable insulator.
However we are not aware of a
transparent magnetically-permeable
insulator material. Thus realizing high
performance TTFIs and related
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
20/23
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
21/23
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
22/23
Actual applications have been reported exploitingthe transparency of TAOSs until now. Transparent
circuits will have unprecedented applications in
flat panel displays and other electronic devices,
such as see through display or novel displaystructures. Here, practical examples taking
advantage of the transparency of TAOS TFTs are:
Reversible Display,FrontDrive Structure for Color
Electronic Paper, Color Microencapsulated
Electrophoretic Display, Novel Display Structure
Front Drive Structure. Indiumoxide nanowire
mesh as well as indium oxide thin films were used
to detect different chemicals, including CWA
simulants.
-
8/11/2019 presentation1-120412032430-phpapp01 (1)
23/23