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Page 39
Nano Research & Applications
ISSN 2471-9838
September 11-12, 2017 Amsterdam, Netherlands
20
th
International Conference on
Advanced Nanotechnology
Notes:
Advanced Nano 2017
Technology of nano-structuring of GaN for
surface enhanced Raman spectroscopy
measurements
I
t is commonly accepted that the presence of so-called
hot-spots is necessary for obtaining high enhancement
factor (EF) of Raman signal from individual molecules
attached to the plasmonic metal particles. It was
experimentally confirmed that organic (biological,
chemical) molecules located at hot-spots contribute
most significantly to the overall surface enhanced
Raman spectroscopy measurements (SERS) intensity.
Two approaches are usually used in order to deliver
SERS platforms, namely planar and nano-structured
substrates, both with plasmonic metal particles on
the top surface. It has been shown experimentally
that 3D SERS substrates are more efficient for SERS
measurements compared with planar substrates. The
aim of this presentation is to demonstrate the technology
of nano-structuring of hetero-epitaxial GaN substrates
using different (photo)-etching methods as well as
tailoring of plasmonic metal surfaces for increased
SERS efficiency. Highly rough and stable GaN surface
are formed by defect-selective photo-etching of GaN
layers containing dislocations. The resultant nano-
pillars contribute to the formation of hot-spots and high
EF. It will be shown that orthodox etching yielding well
developed pits also leads to the formation of hot-spots
and EF up to 10E6 for the examined test molecules
of para-mercaptobenzoic acid (pMBA). The efficiency
of SERS platforms can also be tailored by chemical
treatment (dealloying) of sputtered alloyed metal layer
of Au-Ag and Au-Cu and by thermal treatment leading
to recrystallization of metal clusters. The novel SERS
platforms based on etched GaN show very good
mechanical and chemical stability and high EF up to
10E7. This feature enabled time-lapse measurements
of various biological systems such as Hepatitis B virus
antigen and DNA and recently of different bacteria (BC,
BT, and BS).
Biography
J L Weyher has completed his PhD at Military Academy of Technology in Warsaw,
Poland and received Habilitation at University of Montpellier in France in 1995. He
is an Associate Professor at Institute of High Pressure Physics in Warsaw. He has
published more than 200 papers in reputed journals.
weyher@unipress.waw.plJ L Weyher
Institute of High Pressure Physics - Polish Academy of Sciences, Poland
J L Weyher, Nano Res Appl 2017, 3:3
DOI: 10.21767/2471-9838-C1-001