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Nanoparticle Synthesis
1. TOP DOWN AND BOTTOM UP
APPROACH FOR NANOPARTICLE
SYNTHESIS
-for 0D,1D,2D,3D particle
A Presentation By
Md .Tariqul Islam-1111030
Muntaseer Bunian-1111001
2. Outlines of the lecture
• Approach to Nanoscale Structure
• Classification of Nanomaterials
• Classification Top-down approach
• TOP-DOWN fabrication of 1D devices
• Bottom-up approach
• Bottom Up Approach of 1D Devices
3. Classification of Nanomaterials
0D, 1D, 2D and 3D
nanostructured
materials
Zero dimensional (atomic
clusters, filaments and cluster
assemblies
one dimensional (multilayers)
two dimensional (ultrafine-
grained overlayers or buried
layers)
three dimensional nanostructures
(nanophase materials consisting
of equiaxed nanometer sized
grains)
8. TOP-DOWN fabrication of 1D devices
A top-down approach to making one-
dimensional quantum devices. Like resonant
tunneling via quantum dots. Method
pioneered by Randall and Reed at Texas
instruments in the late 1980s. However,
rather unsatisfactory device properties due
to fabrication induced damage and poor
lateral control.
9. Bottom-up approach
The opposite of the top-down approach.
• Instead of taking material away to make structures, the bottom-up
approach selectively adds atoms to create structures.
11. Bottom -up approach
-Basic MechanismStart with bulk wafer
Alter area of wafer
where structure is to be
created by adding
polymer or seed
crystals or other
techniques.
Grow or assemble
the structure on the
area determined by
the seed crystals or
polymer. (self
assembly)
Process
Similar results can be
obtained through
bottom-up and top-
down processes
13. Bottom-up fabrication of 1D devices
We have developed an alternative approach, to form
1D nanowires (NWs) by a bottom-up, or
selfassembling, method, allowing simple as well as
highly complex structures to be formed. In most cases
we combine a lithographic step such that the
fabrication can be described as guided self-assembly.
A special benefit of the seeded NW growth approach
is that III-V materials and devices can be grown on
silicon
Array if Zn blend InAs
nanowires with perfectly
periodic twin-plane super
lattice.
14. References
Hench, L. L.; West, J. K. (1990). "The sol-gel process". Chemical Reviews 90: 33.
doi:10.1021/cr00099a003.
Buzea, C.; Pacheco, I. I.; Robbie, K. (2007). "Nanomaterials and nanoparticles: Sources
and toxicity". Biointerphases 2 (4): MR17–MR71. doi:10.1116/1.2815690. PMID
20419892.
Mnyusiwalla, Anisa; Daar, Abdallah S; Singer, Peter A (2003). "Mind the gap : science and
ethics in nanotechnology". Nanotechnology 14 (3): R9. Bibcode:2003Nanot..14R...9M.
doi:10.1088/0957-4484/14/3/201
Alemán, J.; Chadwick, A. V.; He, J.; Hess, M.; Horie, K.; Jones, R. G.; Kratochvíl, P.; Meisel,
I.; Mita, I.; Moad, G.; Penczek, S.; Stepto, R. F. T. (2007). "Definitions of terms relating to
the structure and processing of sols, gels, networks, and inorganic-organic hybrid
materials (IUPAC Recommendations 2007)". Pure and Applied Chemistry 79 (10): 1801.
doi:10.1351/pac200779101801.