Hybrid Materials: a bottom-up approach for nanotechnology
applications
Laura Brigo, Erika Zanchetta, Gioia Della Giustina, Giovanna Brusatin
*
Industrial Engineering Department and INSTM, Via Marzolo 9, 35131 Padova, Italy
ABSTRACT
Engineered organic-inorganic hybrid materials, HyMat, offer new opportunities for the easy, fast and cheap development
of miniaturized functional devices. The integration of inorganic oxide networks, organic functional groups and optically
active molecules or nanoparticles allows to obtain combinations of properties and structures otherwise impossible with
traditional materials.
In particular, a simple and highly versatile synthesis platform enabling preparation of HyMat is presented, which is built
up by a bottom-up sol-gel approach at low processing temperatures. A few types of key building blocks pave the way for
accessing HyMat and make up their formulation, providing a means to synthesize innovative materials enabling to get:
- optically active micro and nanostructures;
- miniaturized sensors for analytes in gaseous or liquid media;
- direct patternability with a range of lithographic techniques;
- variable inorganic and organic compositions, and controlled porosity.
Examples of micro and nanostructures based on these spin-on materials with ceramic (i.e. SiO
2
, GeO
2
, Al
2
O
3
, ZrO
2
,
TiO
2
,) and hybrid compositions will be presented for different applications including plasmonic or fluorescent sensors,
dry-etching masks with outstanding resistance, optically active micro and nanostructured platforms and high resolution
patterns.
Keywords: hybrid materials, sol-gel, lithography, resist, inorganic oxides, direct patterning
1. INTRODUCTION
Structuring surfaces by a direct lithographic process is uncommon. A functional organic or inorganic material is
generally indirectly patterned, by patterning a sacrificial resist deposited on it first, and then by transferring the image of
the sacrificial layer to the functional material, in a pattern-transfer step (Figure 1a). Nevertheless, this multi-step process
often causes a deterioration of lithographic performance, is time-consuming, and makes the process complicated.
Alternative procedures, mainly used to pattern inorganic films, attempt to simplify the traditional complex process using
an organic resist pattern as a mould, depositing the film on it and then removing the organic resist by a lift-off process,
leaving the patterned structures on the substrate.
1
Therefore, it is essential to broaden the spectrum of spin-on materials
that behave as resists (as they proficiently interact with radiation or undergo modifications under specific thermal and
pressure conditions and are further processable with development steps) but that can also be employed as final device
materials (Figure 1b and c).
Organic–inorganic hybrid materials are emerging as an alternative to organic polymers for micro and nanolithography,
guaranteeing both solution processability and higher lithographic performance, stability and a wider choice of
properties:
3-7
thermal resistance (up to 300 °C), mechanical resistance (antiscratch), chemical endurance (resistance to
dissolution). Furthermore, functional properties such as optical (i.e. refractive index), electrical, porosity, etc. can be
tuned, and specific functions can be achieved by embedding nanoparticles, dyes or other active molecules, for
*
giovanna.brusatin@unipd.it; phone +39-049-8275723; www.hymat.dii.unipd.it
Invited Paper
Nanophotonic Materials XI, edited by Stefano Cabrini, Gilles Lérondel, Adam M. Schwartzberg, Taleb Mokari,
Proc. of SPIE Vol. 9161, 91610B · © 2014 SPIE · CCC code: 0277-786X/14/$18 · doi: 10.1117/12.2066677
Proc. of SPIE Vol. 9161 91610B-1
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