ZnO-nanostructures based devices_Cortes

1. ZnO nanostructure
ZnO-nanostructure based devices
Jean P. Cortes

2. Outline
What is ZnO?
Wh t i Z O?
Applications
Nano-LEDs
Principle
Synthesize Optics.org/cws/article/research/26557
Proposal and applications
Nano generator
Nano-generator
Principle
Synthesize
Proposal and applications
Why? See Ref. [4]

3. What is ZnO?
•I
Inorganic compound
i d
• metal oxide
• M lti l f
Multiple forms:
• semiconductor (p- and n- type)
• with wide band gap
gp
• powder
• nanostructures http://4.bp.blogspot.com/_TZ4zYEBSw1I/RjZEF1
FkGCI/AAAAAAAAA8s/-
Vxz6PVYVtI/s320/nano_zinc_1.jpg
• Non-toxic
• Found on:
• paints
it
• cosmetics
• lotions/sunscreens http://www.zxzinc.com/UploadFiles/200
p p
71015195726571.gif

4. Applications
Energy production
Sensors
nano-generator
gas sensors
Coatings
bio sensors
Optoelectronics wear resistance
Filtering
emission device (LED,
(LED
laser diodes)
desalination
non linear optical
Photovoltaic
devices
di
detector device (UV-
nanostructure Solar
detector))
cells
ll
Metrology
AFM cantilever

5. Case 1 Principles of LED
Diode that emits light by the movement of electrons in
a semiconductor.
Emission UV, visible or infrared regions.
, g
Unlike ordinary incandescent bulbs, they don't have a
filament that will burn out and they don't get hot.
= p-n Electrical
junction
j ti Contacts
Ctt

6. Case 1 flexible Nano-LEDs by Ref. 1
Flexible Nanowire Light-Emitting Diode
Polymer ZnO LED
See Ref. [1]
Au PS ( l t
(polystyrene)
)
ZnO nanowires/nanorods
ITO (indium-tin-oxide)
PET foil (polyethylene terephatate)

7. Case 1 Nano-LEDs synthesis
See Ref. [1]
(Pt)
ED advantages:
ITO - Electrolyte:
onto
3 mM ZnCl2, 5μM AlCl3, and
PET
Gas
0.1 M KCl.
input
(O2, N2) - AlCl3 to improve
T=80oC
conductivity on the
nanorods increase
emission intensities
intensities.
- very good adhesion
between ZnO nanowires
Electrolyte
and substrate
substrate.
** Typical electrodeposition (ED) cell with
aqueous chemical growth **

8. Case 1 Proposal
- ED with aqueous chemical that will
produce ZnO nanowires.
- use any type of polymer carrier
material (i.e. PDMS)
( )
- use the DC magnetron sputtering
(for anode and cathode)
- characterize fi t nanostructure and
h t i first t t d See Ref. [2]
then see how can we improve light.
- package our device for further
applications:
– Low cost
– Large surfaces
– Industrial compatibility
p y
– Highly ordered vertical ZnO
nanowires
source Cree Inc.
– Flexible and robust substrate.

9. Case 1 Applications
Incandescent LED Light Fixture
5135 W Total 948 W Total
source Philips source Cree Inc.

10. Case 2 Principle of Nano-generator
PZ: piezoelectric effect (inside of semiconductors such as
p (
ZnO) is the ability of a crystalline structure to generate an
electrical current with applied stress and backwards.
Mechanical energy
Vibrational energy
Chemical energy (glucose)
hydraulic energy
= Direct Current
http://www.school-for-
p
champions.com/science/images/static_c
auses-piezoelectric.gif

11. Case 2 Nano-generator by Ref. 3.
Schematic of the interacting between AFM tip with ZnO
nanowires. See ref [4]
Nanowires
The pioneer
Dr. Zhong Lin Wang
A prototype direct‐current
nanogenerator was
developed by Georgia Tech researchers
using an array of zinc oxide nanowires. See Ref. [3]
Nanobelts
ZnO NW / NB Pros:
- Simple / Cost Efficient / Non-toxic
- C b subjected to extremely l
Can be bj d l large elastic d f
l i deformation without
i ih
deformation or fracture
- Can be bent with little force
- Small diameter free of dislocation higher resistant of fatigue

12. Case 2 Proposal (I)
Thermal Evaporation
-V
Vapor S lid (VS)
Solid Nanobelts
N b lt
1. Small tube furnace low cost
2. Zn atoms evaporate from Zn powder under
a heating process
3. Zn + 02 ZnO vapor deposited on the
walls of the quartz tube
4. No catalyst needed
- Fabrication Techniques = f (T and Distance)
http://nano.materials.drexel.edu/Facilities/FacilitiesImage/TubeFurnace.jpg

13. Case 2 Proposal (II)
Metal-Organic Chemical Vapor Deposition
(MOCVD)
– uses a metal-organic gas source (Zn
precursor Zn(C2H5)2 or
(CH3)2Zn-N(CH2CH3)3), O source = N2O)
– Precursor is heated to its gas phase
– Carried to a heated substrate by a carrier
gas
– react with the substrate to deposit the
solid product ZnO nanowires
Why preferred?
– High purity RF Micro Devices of Charlotte. The machine is a custom-built flow
– Large area growth
modulation epitaxial (FME) metal organic chemical vapor deposition
(MOCVD) reactort
– Control of film thickness
– High growth rates
– Preferred structural orientation

14. Case 2 Applications
Power to biomedical detection and monitoring
g
devices
Portable Electronics
Long Term applications
Alternative Energy Applications

15. Why ZnO nanowires?
Case 1. Nano-LEDs 160 lumens/W.
- reduce the amount/consumption of electricity compared
with incandescent lights (20 lumens/W).
- l CO2 and di ti l li ht emission.
less d directional light ii
- device stability
- ultra-low current / voltage / power operation
- reliability and long lifetime
- maintance avoidance
- rugged
Case 2. Nano-generator
- convenient/portable alternative to battery packs
- Provides power to nanodevices
- Portable electronics
- Implantable medical devices
- Biosensors

16. References
Case 1.
1. Nadarajah Athavan, Robert Word, and Jan Meiss. quot;Flexible inorganic nanowire Light-
Emitting diode.quot; Nano Letters 8.2 (2008): 534-537.
2. Park, S.-H, Kim S.-H, and Han S.-W. quot;Structural Properties of Nitrogen-Ion implanted
ZnO Nanorods.quot; k
Z ON d quot; korean Ph i l S i t 50 (2007) 1557-156.
Physical Society (2007): 1557 156
Case 2.
3.
3 Wang,
Wang Zhong Lin quot;Piezoelectric Nanostructures: From Growth Phenomena to Electric
Lin. Piezoelectric
Nanogenerators.quot; MRS Bulletin 32 (2007): 109-116.
4. Wang, Xudong, Jinhui Song, Jin Liu, and Zhong Wang. quot;Direct-Current Nanogenerator
Driven by Ultrasonic Waves.quot; Science 316.5821 (2007): 102-105.
5.
5 Cheng , S J G R Whang and Y.C. Liu. quot;the structure and photoluminescense
S.J., G.R. Whang, Y C Liu
properties of ZnO nanobelts prepared by thermal evaporation.quot; Journal of
Luminescense 129 (2008): 340-343.
6. Li, J. Y., Q. Zhang, et al. (2009). quot;Diameter-Controlled Vapor-Solid Epitaxial Growth and
Properties of Aligned ZnO Nanowire Arrays quot; Journal of Physical Chemistry C 113(10):
Arrays.
3950-3954.
7. Wang, Z. L. (2008). quot;Towards Self-Powered Nanosystems: From Nanogenerators to
Nanopiezotronics.quot; Advanced Functional Materials 18(22): 3553-3567.

17. That’s ll F lk !
Th t’ all Folks!