1. Babes-Bolyai University Molecular Spectroscopy Group
PHOTONIC NANOSTRUCTURES WITH CONTROLLABLE AND MULTIFUNCTIONAL PROPERTIES
Simion Astilean
Babes-Bolyai University
Faculty of Physics
Molecular Spectroscopy Group
Cluj-Napoca

2. Current challenge of nanofabrication
To control: the size, shape, composition, spatial organization and chemical (biological) function of nanostructures
Artificial nanostructures meet biomolecules

3. Main points of our research
Developing an experimentally inexpensive method of controlled nanofabrication:
The method is based on self-assembling process and nanosphere lithography and is able to fabricate large-area of highly ordered and shape-size-controlled nanostructures.
Fabrication of multifunctional photonic nanostructures:
Periodic arrays of noble-metal nanoparticles,
Periodic arrays of nanoholes in metallic films,
Photonic crystals,
Self-assemblies of functionalized polymer nanospheres,
Etc.
Using light (photons) to extract and process information on the nanoscale:
Optical bio-chemo-sensing,
Ultrasensitive spectroscopic analysis,
Photonics application,

4. Work on progress

5. Starting with self-assembly of polystyrene nanospheres
1. Drop ~120 L colloid soln.
onto hydrophillic substrate.
2. Dry in oven, spheres self assemble
at meniscus edge.

6. SEM pictures of self-assembled monolayer of polystyrene nanospheres
Starting with self-assembly of polystyrene nanospheres
SEM pictures of self-assembled monolayer of polystyrene nanospheres

7. AFM and SEM pictures of self-assembled multi-layers of polystyrene nanospheres

8. Using self-assemblies of polystyrene nanospheres as templates for nanolithography
1. Thermally evaporate layer
of silver or gold onto
the polystyrene nanosphere
array.
2. Combining nanosphere lithography with Reactive Ion Etching (RIE)

9. Using self-assemblies of polystyrene nanospheres as templates for nanolithography
1. Regular Arrays of Noble-Metal Nanoparticles
2. Regular Nanoscale Hole-Arrays
in Noble-Metal Films

10. Photonics Properties of Regular Arrays of Noble-Metal Nanoparticles
Optical response of noble metal nanoparticles is dominated by the Localized Surface Plasmon Resonance (LSPR).
Large near-field enhancement relative to incident field.
Tunable Optical Response by altering particle size, shape, environment and proximity.

11. Photonic Properties of Nanoscale Hole-Arrays in Metallic Films
Periodic structure of hole-arrays enables coupling light to surface plasmon (SP) mode.
Evanescent field emerges through holes and is coupled to radiative modes.
Giant optical transmission of sub-wavelength apertures.

12. (C) Combining Nanosphere Lithography with Reactive Ion Etching (RIE)
1. Etch nanosphere array in an oxygen plasma
2. Remove nanospheres leaving hexagonal array of holes in a metal film

15. Applications

16. Nanostructures for optical chemo-bio-sensing applications
Metal
Light
Plasmon
100 nm
Linker
Biomolecule FG
Nanosized optical biosensors based on surface plasmons resonances (SPR)
Biomedical applications
Conventional instruments
Advantages of this approach
receptor-ligand interactions;
DNA hybridization;
enzyme-substrate interaction
protein conformation studies
label-free immunoassay;
high-throughput screening in pharmaceutical industry;
uses expensive sensor chips;
limited reuse capacity;
complex chemistry for ligand or protein immobilization
nanostructured support is cheap and easily synthesize;
can be coated with various proteins or protein-ligand complexes by charge adsorption;
monitored in any UV-vis spectrophotometre;

17. Surface Plasmon Resonances

18. Nanostructures for photonic applications
Controlling the propagation, emission and detection of light on the nanoscale
Novel spectroscopic tools for ultrasensitive analysis
Novel class of optical materials
Novel light sources
Single Molecules Spectroscopic Fingerprint
Fluorescence decay control
Surface Enhanced Raman Scattering (SERS)
Surface Enhanced IR Absorption (SEIRA)
Photonic Crystals
Photonic Integrated Circuits
Telecommunication Devices
Zero-Threshold Lasers
Single - Photon Light Sources
Quantum Information Devices

19. SERS Results

20. Fluorescence Decay Control

21. Interdisciplinary approach

22. Required techniques for fabrication, processing and characterization of nanostructures
Structural
Chemical
Optical
Other
TEM
AFM
XRD
Confocal optical microscopy
Surface chemistry*
Nanosphere synthesis
and functionalization
Bioconjugation and linkage
UV-vis spectroscopy*
Fluorescence spectroscopy and lifetime measurements
Raman spectroscopy* (microRaman, SERS)
Infrared spectroscopy*
Reactive ion etching
Metal film deposition
Modeling and Computing techniques*
RMN
EPR
* Our laboratory facilities

23. We are looking for partners…
Groups already contacted and interested in this research
National
1. Centrul de Biologie Moleculara (Institutul de Cercetari Experimentale interdisciplinare al Univ Babes-Bolyai, Cluj-Napoca)
2. Laboratorul de Materiale Nanostructurate Avansate (INCDTIM, Cluj-Napoca)
3. Catedra de Macromolecule (Univ Tehnica Gh Asachi, Iasi)
4. Institutul National de Chimie Macromoleculara P. Poni (Iasi)
5. Centrul de Fizica Plasmei, (Facultatea de Fizica, Univ. Al I Cuza, Iasi)
International
1.Prof Sigrid Avrillier, Lasers Physics Laboratories, Paris University and SOPRA, France
2.Prof Gerard Bidan, Laboratoire d’Electrochimie Moleculaire et Structures des Interfaces, DRFMC, CEA, Grenoble, France.
3.Dr Anne Corval and Dr Patrice Baldeck, Laboratoire de Spectrometrie Physique, Univ Joseph Fourier Grenoble France
4.Prof Arnulf Materny, School of Engineering and Science, International University Bremen, Germany
5. Prof WL Barnes, School of Physics, University of Exeter, UK
6.Dr Gilad Haran, Single Molecule Laboratory,Weizmann Institute, Rehovot, Israel
7.Dr Victor Weiss, Optronic Center, ELOP Electrooptics Industries Ltd, Rehovot, Israel
8.Dr Peter Persephonis, University of Patras,
Patras, Greece
We are looking for partners…

24. Conclusions and Perspectives
This project develops an experimentally simple technique for controlling the fabrication of nanostructures.
The fabricated nanostructures have a real potential for relevant biosensing, photonics and ultrasensitive spectroscopic applications.
This method of nanofabrication could be extended to semiconductors, polymer, ceramics and magnetic materials.