Director of CAMOS
Dr. Kurt W. Kolasinski
Kurt W. Kolasinski ,
Director CAMOS Ultrafast Laser Facility since July 2004. Moving to the Department
of Chemistry, West Chester University in August 2006.
science / reaction
dynamics / laser
photochemistry / laser-surface
interactions / nanotechnology / physical
chemistry / chemical
My research centers on the study of dynamical processes at the surfaces
of metals and semiconductors with a special emphasis on structure formation
and laser-surface interactions. Along these lines we are studying photochemical
and thermal reactive processes on surfaces. Of special interest are etching
and growth reactions to form nanoscale and larger structures.
Dynamics of Adsorption and Desorption
I've long studied the simplest of surface chemical reactions, the adsorption
and thermal desorption of small molecules from surfaces,
on silicon. I've also recently reviewed stimulated
desorption of hydrogen from silicon.
Currently together with Professor Ian
Harrison, we are examining the dynamics of methane adsorption on metal surfaces.
CH4 is a molecule that is very important in a range of catalytic chemistry.
Methane is the primary component of natural
gas and steam reforming of methane over a nickel catalyst is the primary industrial source
Photochemical & Chemical
Modification of Si and Porous
Si is a pure elemental semiconductor, the most widely used in integrated circuit
applications. Irradiation with laser light fundamentally alters the surface chemistry
of silicon. For instance, whereas clean crystalline Si is virtually inert to
aqueous hydrofluoric acid,
irradiation of a Si
crystal immersed in HF(aq) with a cw visible laser can lead to the formation
Si . Once formed, the reactivity of porous Si can
also be altered by irradiation. We are studying these processes in order to determine
what factors affect the photochemical reactivity of Si surface and to develop
a mechanistic understanding of the
We have also extended this work to investigate the formation of porous silicon
by purely chemical methods, so-called stain etching. In stain etching an oxidant
is mixed with fluoride to form an aqueous solution that spontaneously produces
porous silicon once a silicon crystal has
been dipped in it. We have already shown that
the fluoride can be provided not only by HF but also by NH4HF2.
We are now investigating the role of the oxidant and how it can be used to
control both the photoluminescence spectrum and the morphology of
the por-Si film.
There is great interest in obtaining light from nanoscale Si [see links
( 1 ), ( 2 )
and ( 3 )]
structures for optoelectronic, nanoelectronic and biomedical applications,
even fuel cells .
Working with porous silicon has
its advantages. Not only is there a lively community
of researchers in the field but we also like to meet at
the beach in Tenerife or Catalonia or sometimes
on a volcano such as El Teide in Tenerife.
Silicon Pillar formation
irradiation of Si crystals under the appropriate conditions can lead to the
spontaneous formation of conical structures. When made with a femtosecond laser,
can be ten or so micrometers long. The tips, however, are on the order of a
few hundred nanometers or less. Using a nanosecond laser, the pillars are much
up to 100 µm or more and a few micrometers at their tip.
We are currently investigating the optical and chemical parameters that influence
the growth and morphology of these pillar films. We will also study the geometric
and electronic structure of these films by means of scanning
tunneling microscopy, Raman
spectrsocpy and electron microscopy,
among other techniques.
We are studying methods of pretreatment that lead to ordered arrays of pillars
and post-irradiation chemical treatments that lead to porous
pillars or sharpened
pillars. As shown in the micrograph, we have used to KOH etching of the
pillars to produce 10 nm tips on 100 µm tall pillars. These are perhaps
the highest aspect ratio features ever made in silicon.
Ultrafast Surface Photochemistry in the VUV
In a collaborative effort with Professor RE Palmer (Nanoscale Physics Research
Laboratory, Birmingham) and Dr JS Foord (Physical & Theoretical Chemistry
Laboratory , Oxford), a rather unique machine to study ultrafast (about 1
ps or less) photochemistry in the vacuum ultraviolet regime has
been constructed. We make the required photons through a
laser-based technique: high harmonic
generation with an Ar-ion-pumped Ti:sapphire
laser . This laser produces roughly 80 fs pulses at a wavelength near 800
nm. The output of the Ti:sapphire laser is focused into a rare gas. A nonlinear
interaction between the laser field and the atoms in the rare gas jet creates
the photons that we are after: ~10-40 eV or 120-30 nm.
We have studied the photochemistry
of O 2 adsorbed on graphite. This
was the first use of HHG to initiate surface photochemistry. To learn more about
lasers, try this tutorial.
This project is part of a TMR Network which you can learn more about here .
Being part of a TMR network is often hard work, including walking up snowy
moutain roads and skiing.
Selected Recent Publications:
Laser assisted and wet chemical etching of silicon nanostructures, Kurt W.
Kolasinski, David Mills and Mona Nahidi, J.
Vac. Sci. Technol. A 24, 1474-1479 (2006).
Silicon nanostructures from electroless electrochemical etching, Kurt W. Kolasinski,Curr.
Op. Solid State & Mater. Sci. 9, 73-83 (2005).
Surface photochemistry in the VUV and XUV: High harmonic generation, H2O
and O2, Kurt W. Kolasinski, J.
Phys Cond. Matter 18, S1655-S1675 (2006).
Solidification driven extrusion of spikes during laser melting of silicon pillars,
David Mills and Kurt W. Kolasinski, Nanotechnology 17,
Using effusive molecular beams and microcanonical unimolecular rate theory to
characterize CH4 adsorption on Pt(111), Kristy M. DeWitt, Leticia
Valadez, Heather Abbott, Kurt W. Kolasinski and Ian Harrison, J.
Phys. Chem. B 110, 6705-6713 (2006).
Effusive molecular beam study of C2H6 dissociation on Pt(111),
Kristy M. DeWitt, Leticia Valadez, Heather Abbott, Kurt W. Kolasinski and Ian
Harrison, J. Phys. Chem. B
110, 6714-6720 (2006).
The effects of stain etchant composition on the photoluminescence and morphology
of porous silicon, Mona Nahidi and Kurt W. Kolasinski, J. Electrochem. Soc., 153, C19–C26
The Composition of Fluoride Solutions, Kurt W. Kolasinski, J.
Electrochem. Soc., 152 (9), J99–J104 (2005).
Non-Adiabatic and Ultrafast Dynamics of Hydrogen Adsorbed on Silicon, K.W. Kolasinski, Curr. Op. Solid State & Mater.
Sci, 8, 332-333 (2004).
Non-lithographic method to form ordered arrays of silicon pillars and macropores,
David Mills and Kurt W. Kolasinski, J. Phys D. 38 (2005)
Laser-assisted restructuring of silicon over nano-, meso- and macro-scales, K.W.
Kolasinski, in Recent Research Developments in Applied Physics, edited by S.G.
Pandalai (Transworld Research Network, Kerala, India, 2004), Vol. 7, pp. 267-292.
Laser-etched silicon pillars and their porosification, David Mills and Kurt W.
Vac. Sci. Technol. A 22, 1647 (2004).
Arranged silicon conical
spike structures from optical diffraction and ultrafast laser etching in
halogen gas, D. Riedel, J.L. Hernández-Pozos,
K.W. Kolasinski and R.E. Palmer, Appl. Phys. A 78, 381
The mechanism of Si etching in fluoride solutions, K.W. Kolasinski, Phys.
Chem. Chem. Phys., 5, 1270 (2003) .
Textbook on Surface Science:
Kurt W. Kolasinski, Surface
Science: Foundations of Catalysis and Nanoscience ( John
Wiley & Sons , Chichester, 2002).
Accompanying website for
the book , including the figures in pdf format
Take A Course in Surface Science Electronically
Iowa State University : Chemistry
(Chem) 586X--Surface Science
Course: Chemistry (Chem) 586X, section XW
For a full list of publications click here .
For further information on related topics, try these sites:
Sites in Surface
Science, Nanotechnology and Catalysis
Web Resources in
Surface Science, Nanotechnology and Catalysis
Surface Science, Nanotechnology and Catalysis
in Surface Science, Nanotechnology and Catalysis
Physics and Catalysis Societies
The Pittsburgh Penguins
Dynamics of Gas-Surface Interactions
Last update : 7 August 2006