Wednesday, August 3, 2016 3:00 pm
-
4:00 pm
EDT (GMT -04:00)
The Waterloo Institute for Nanotechnology (WIN) presents a seminar by Professor Jan Dubowski, holder of the Canada Research Chair in Quantum Semiconductors and a Fellow of the International Society for Optical Engineering from the Department of Electrical and Computer Engineering at Universite de Sherbrooke, Quebec.
Photocorrosion of fictionalised GaAs/AlGaAs nano-heterostructures
Abstract
III-V
semiconductors
have
played
key
role
in
the
development
of
optoelectronic,
fast
speed
microelectronic,
photovoltaics
and
some
other
photonic
devices.
However,
the
sensitivity
of
these
materials
to
moisture
and
oxygen,
e.g.,
the
photocorrosion
of
GaAs
in
aqueous
solutions
is
a
known
drawback
limiting
the
use
of
this
material
for
solar
energy-conversion,
requires
application
of
surface
protecting
physical
and/or
chemical
methods.
If
induced
to
proceed
at
a
nanoscale
rate,
the
photocorrosion
of
GaAs/AlGaAs
heterostructures
reveals
a
measurable
sensitivity
to
the
presence
of
electric
charge
accumulating
at
their
surfaces.
Functionalization
of
the
GaAs
surface
with
alkanethiol
self-assembled
monolayers
allows
working
with
architectures
designed
for
specific
immobilization
of
charged
molecules
in
the
vicinity
of
a
photocorroding
surface.
I
will
discuss
the
conditions
required
to
control
photocorrosion
of
GaAs/AlGaAs
heterostructures
at
the
nanoscale
rate,
and
I
will
demonstrate
the
application
of
a
photoluminescence
monitored
photocorrosion
to
sensing
electrically
charged
bacteria
immobilized
on
functionalized
surfaces
of
GaAs/AlGaAs
nano-heterostructures.
In
addition
to
the
rapid
detection
of
bacteria,
the
photocorrosion-based
approach
has
enabled
us
to
investigate
the
reaction
of
bacteria
captured
on
the
GaAs
surface
(yes,
bacteria
can
grow
on
GaAs)
to
ciprofloxacin
and
penicillin
environments.
The
mechanisms
of
electric
charge
moderated
photocorrosion
and
a
perspective
of
this
approach
for
rapid
evaluation
of
bacterial
reactions
with
different
antibiotics
will
also
be
discussed.