A detailed description of the basic concepts involved in transparent electronics.

1. SPEAKER: AKSHAY K
Sunday, February 28, 2016 1IEEE Electron Devices Society

2. WHAT GOOGLE SAYS….
 Transparent electronics is an
emerging science and technology field
focused on producing
'invisible' electronic circuitry and
opto-electronic devices
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3. Why become invisible?
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4. APPLICATIONS
 Smart car wind shield
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5.  SOLAR PANEL EMBEDDED WINDOW
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6. CONCEPT VIDEO
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7. ASSOCIATED FIELDS
INVOLVED
 Multi disciplinary study involving
material science ,chemistry, physics,
band engineering ,device
engineering, circuit engineering etc:
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8. TRANSPARENT
ELECTRONICS
 When do you say something is
transparent?
*Conditions on bandgap for transparency
Bandgap>3.1eV(violet)e
*Conditions on bandgap for non transparency
Bandgap <3.1eV(violet)e
Transparency Vs Conductivity
CONTRODICTORY
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9. Transparent Conducting
Oxide(TCO)
 WHY TCO? Is it naturally occurring?
 ITO- A common TCO (TCO host-In2O3)
 Other potential TCO host: SnO2, CdO
and ZnO
 ITO on glass and ITO on
plastic –Electrodes in
transparent electronics
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10. QUESTIONS CORNER!!!
 How does something become a TCO
host?
 How we make a TCO Host into an
actual Transparent Conducting Oxide?
SOLN: BAND GAP ENGINEERING
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11. Band formation
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12. BAND GAP ENGINEERING
 Band-gap engineering is the process
of controlling or altering the band gap of
a material.
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13. Why band engineering needed
here?
 Transparent because their energy gap is
large.
 Large bandgap => very less intrinsic
concentration.
 So an intelligent band diagram alteration
required to increase conductivity and still
maintain optical transparency.
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14. BAND DIAGRAM
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HOW DO WE INCREASE CONDUCTIVITY?
SOLN: DOPING

15. Where should the donor level
be placed?
 Closer to CBM?
 Closer to VBM?
 Middle of Band gap?
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16. MODIFIED CONDITION FOR
OPTICAL TRANSPARENCY
All following energy gaps must be out of
visible spectral energies.
 CBM-Ed
 Ed-VBM
 CBM-VBM
<1.77eV
>3.1eV
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17. How much doping required?
 Degenerate doping required to improve
conductivity.
ISSUE WITH DEG: DOPING
 Donor level splits up to form donor band
 How much split? What is the limit?
soln: Donor band width< 1.77eV
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18. IDEAL TCO
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19. Another band gap engineering
brilliance !!!!
PROBLEM:
 CdO (a material of high industrial use)
has band gap 2.3 eV.
 Lies in visible spectral energy range.
 What do we do to make it transparent?
Soln: BURSTEIN MOSS EFFECT
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20. Sunday, February 28, 2016 IEEE Electron Devices Society 20

21. BURSTEIN MOSS
EFFECT
 On degenerate doping, all available states in CBM
is fully occupied.
 So the effective band gap increases and it comes
out of the optical transparency window.
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22. PRODUCT FLOW
PATH IN
TRANSPARENT
ELECTRONICS
materials→
devices → circuits
→ systems
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23. CIRCUIT COMPONENTS
ACTIVE
 Bipolar transistors,
Mosfets, Finfets
PASSIVE
 Eg: resistor, capacitor,
inductor
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24. PASSIVE LINEAR DEVICES
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25. TTFR (Transparent Thin Film
Resistors)
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(a) Plan-view of a straight-line
or linear transparent thin-film
resistor
(TTFR) (16 squares)
(b) a meander TTFR. (36
squares, still same area)
(c) Cross-sectional view of a
TTFR in which
contacts and passivisation are
also indicated

26. SCOPE OF RESEARCH!!!!
 For Thin Film Resistors(TFR) laser
trimming is performed for precision and
accuracy and reduce tolerance. Nothing
similar is discovered in transparent
electronics domain. So industry is
waiting for an efficient method to
improve accuracy of TTFR.
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27. LASER TRIMMING
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28. TTFC
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29. TTFT
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30. REFERENCES
 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. Marks.
 www.ieee.org
 www.wiley.com
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31. THANK YOU
FOR PATIENT LISTENING!!
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