Miss Shahida Transparent Electronics Submitted by Sajas KK Roll no 18 S5 EC Introduction What is transparent electronics In transparent electronics the usual opaque semiconductor materials forming the basis for electronic devi ID: 575073
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Slide1
Guided by Miss. Shahida
Transparent Electronics
Submitted by,
Sajas
K.K.
Roll no: 18
S5 ECSlide2
IntroductionWhat is transparent electronics?
In transparent electronics the usual opaque semiconductor materials forming the basis for electronic device fabrication is replaced with transparent materials.Slide3
There are two technologies which preceded and underlie transparent electronics:
Transparent Conducting Oxides (TCOs)Thin Film Transistors (TFTs)Slide4
Transparent Conducting Oxides TCOs)
TCOs constitute an unusual class of materials possessing two physical properties (generally considered mutually exclusive):High optical transparency. ( Eg>3.1eV)
High electrical conductivity.
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Transparent Passive devices Transparent Thin Film Resistors
Transparent Thin Film Capacitors Transparent Thin Film InductorsSlide7
Transparent Thin Film ResistorsSlide8
Resistive material: ITO (Indium Tin Oxide)
Typical sheet resistance ~ 10-
Conductivity of TCO’s depends on number of oxygen vacancies (
and metal atoms occupying interstitial sites.
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Transparent Thin Film CapacitorsSlide10
Most insulators are transparent.
Contact layer is made of highly conducting TCOs (ITO).
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Transparent Thin Film Inductors
Hard to realize due to poor conductivity of TCO’s compared to metals.
High L requires larger number of turns which in turn results in increased parasitic resistance.
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Schottky Barriers
Formed from metal (anode)-semiconductor (cathode) junction.Space charge region (depletion region) and potential barrier formation due to difference in work function of metal and semiconductor.Schottky barrier height
, where
Schottky barrier height
work function of
metal
Electron affinity of semiconductor
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Energy band in a Schottky barrierSlide14
Transparent Thin Film TransistorsConstitutes the heart of transparent electronics
Channel is formed from highly insulating, wide band gap transparent semiconductor(ZnO).Source, drain and gate contacts are made from highly conductive TCO (ITO).
Two possible configurations are:
Bottom gate
Top gateSlide15
Possible structure, (a) Bottom gate, and
(b) Top gate.Slide16
Operation of a bottom gate TFTSlide17
Strengths and Weaknesses
Strengths
Weaknesses
Visible transparency
High resistance of TCO’s
Large area
Lack of complementary devices
Low
cost (solution based deposition and printing)
Low frequency of operation.(KHz
to few MHz).
f
T
=
Low temperature processing
Technological immaturity
Free real estate
Passive availability (R & C)
Robust stable inorganic materials
Safe, nontoxic materials
Strengths
Weaknesses
Visible transparency
High resistance of TCO’s
Large area
Lack of complementary devices
Low
cost (solution based deposition and printing)
Low temperature processing
Technological immaturity
Free real estate
Passive availability (R & C)
Robust stable inorganic materials
Safe, nontoxic materials
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ApplicationsActive Matrix LCD (AMLCD).
Active Matrix Organic Light Emitting Device display backplane (AMOLED).Value added glass.
Transparent electronics on opaque substrates.Slide19
UV detectors and arrays
Transparent solar cellsUV detectors for spectrally resolved imaging.Security applications:
Invisible cameras and
Invisible RFID’sSlide20
ConclusionStarted as a mere electrical device technology during world war 2, transparent electronics now holds the key for many future advancements in security, entertainment efficient utilization of energy.Slide21
Reference‘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. MarksSlide22
Thank you