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Magnetic nanoparticles of CoFe2O4 have been synthesized under an applied magnetic field through a co-precipitation
method followed by thermal treatments at different temperatures, producing nanoparticles of varying size. The
magnetic behavior of these nanoparticles of varying size was investigated. As-grown nanoparticles demonstrate
superparamagnetism above the blocking temperature, which is dependent on the particle size. The anomalous
magnetic behavior is attributed to the preferred Co ions and vacancies arrangements when the CoFe2O4 nanoparticles
were synthesized under applied magnetic field. Furthermore, this magnetic property is strongly dependent on the high
temperature heat treatments, which produce Co ions and vacancies disorder. We performed the fabrication of
condensed and mesoporous silica coated CoFe2O4 magnetic nanocomposites. The CoFe2O4 magnetic nanoparticles
were encapsulated with well-defined silica layer. The mesopores in the shell were fabricated as a consequence of
removal of organic group of the precursor through annealing. The NiO nanoparticles were loaded into the
mesoporous silica. The mesoporous silica coated magnetic nanostructure loaded with NiO as a final product may
have potential use in the field of biomedical applications.
Growth mechanism of ZnO nanorod arrays on ZnO seed layer investigated by electric and Kelvin probe
force microscopy. Both electric and Kelvin force probe microscopy was used to investigate the surface potentials on
the ZnO seed layer, which shows a remarkable dependence on the annealing temperature. The optimum temperature
for the growth of nanorod arrays normal to the surface was found to be at 600 °C, which is in the range of right
surface potentials and energy measured between 500 °C and 700 °C. We demonstrated from both EFM and Kelvin
force probe microscopy studies that surface potential controls the growth of ZnO nanorods. This study will provide
important understanding of growth of other nanostructures. ZnO nanolayers were also grown by atomic layer
deposition techniques. These nanolayers of ZnO demonstrate remarkable optical and electrical properties. These
nanolayers were patterned by the Electron Beam Lithography (EBL) technique.
A major goal of nanotechnology is to couple the self-assembly of molecular nanostructures with
conventional lithography, using either or both bottom-up and top-down fabrication methods, that would enable us to
register individual molecular nanostructures onto the functional devices. However, combining the nanofabrication
technique with high resolution Electron Beam Lithography, we can achieve 3D bimolecular or/and DNA origami that
will be able to identify nucleic acid sequences, antigen targets, and other molecules, as for a perfect nano-biosensor.
We have explored some of the nanopatterning using EBL in order to fabricate biomolecule sensing on a single chip
with sub nm pitch. The applications are not limited for the bioactivity, but for enhancing immunoreactions, cell
culture dishes, and tissue engineering applications.
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