Organic Semiconductor
Gaojie Lu
ECE423 Presentation
12-16-2006
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Outline For Organic Semiconductor
Introduction to Organic Semiconductor
Relation of Organic Semiconductors to
Inorganic
Characteristics of Organic Semiconductor
Organic Semiconductor Devices
Future Applications
Summary
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Introduction to Organic Semiconductor
Introduction to Organic Semiconductor
 Organic Semiconductors are semiconductors which
use organic molecules rather than silicon for their
active material. This active material can be
composed of a wide variety of molecules
Low cost of the technology
 Compatibility with plastic substances
 Lower temperature manufacturing (60-120° C)
 Possible to achieve flexible structures
 Low voltages, comparable with the performance
for solution monitoring and some innovative
applications

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Relation of Organic Semiconductors to
Inorganic
 Also studied for more than 50 years
 Huge variety of choices for organic molecules for
use in semiconductors
 Charge transport significantly different
 Usually comprised of many individual molecules
held together by Van der Waals forces
 Many different fabrication techniques on different
substrates
C60
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Relation of Organic Semiconductors to
Inorganic Cont.
 Generally operate under accumulation mode, not inversion mode
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Mobilities of organic semiconductors have improved
by five orders of magnitude over the past 15 years.
Large research efforts using materials such as
these led to some of this increase.
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Organic Semiconductors Device-OLED
 An organic light-emitting diode
(OLED) is a special type of lightemitting diode (LED) in which the
emissive layer comprises a thin-film
of certain organic compounds. The
emissive electroluminescent layer
can include a polymeric substance
that allows the deposition of very
suitable organic compounds
 For example, in rows and
columns on a flat carrier by
using a simple "printing" method
to create a matrix of pixels
which can emit different colored
light.
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Organic Semiconductors Device-OTFT
 TFTs are transistors created using thin films, usually of silicon
deposited on glass. The deposited silicon must be crystallized using
laser pulses at high temperatures.
 For organics to compete with a-S:H, their mobility should be greater
than 0.1 cm²/V s and their on/off current ratio of greater than 106
 OTFTs active layers can be thermally evaporated and deposited at
much lower temperatures (i.e. 60° C)
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Organic TFT Tightness
 Benefits
 Does not require a glass
substrate as amorphous
silicon does
 Low temperature
manufacture
 Could be made on a piece of
plastic
 Deposition techniques could
reduce costs dramatically
 Challenges
 Workarounds for
complications with
photoresists
 Finding organic
semiconductors with high
enough mobilities &
switching times
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Future Outlook
OTFTs for active-matrix displays
Flexible view screens (or anything…)
New generations of smart cards
Organic smart pixels with OLEDs
Large-area display electronics
Organic semiconductor advances in
mobility, switching time, and manufacturing
may lead to many possibilities
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References
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Thank you!
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