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Dr. K.W. Kolasinski Dr.Kurt W. Kolasinski
Department of Chemistry
West Chester University
West Chester, PA 19383 USA 

Tel: (610) 436-2968 (office)
Tel: (610) 738-0386 (lab)
Fax: (610) 436-2890
E-mail: kkolasinski@wcupa.edu 

Surface Science

Kurt W Kolasinski , BA (Pittsburgh) PhD (Stanford) CChem MRSC, Professor of Chemistry, joined WCU 2006.

Academic genealogy
Founding member of the American Physical Society Mid-Atlantic Section.


[Course Information] [Research Interests]  [Publications]  [Useful Links]  [WCU Homepage]  [WCU Chemistry]


Courses Taught

CHE341 Physical Chemistry I

CHE342 Physical Chemistry II

CRL 341 Experimental Physical Chemistry I

CRL 103-104 Experimental General Chemistry I-II

CHE433 Special Topics: Surface Science

          Physical chemistry education resources

Research Interests & Student Research Opportunities


  surface science / reaction dynamics / laser photochemistry / laser-surface interactions / nanotechnology / physical chemistry / chemical physics


Femtosecond Dye Laser
Titanium Sapphire Laser
Ablation YAG

My research concentrates 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 my co-workers and I are studying photochemical and thermal reactive processes on surfaces. Of special interest are etching and growth reactions to form nanoscale and larger structures.

A great deal of my work has involved pointing lasers at or near surfaces and observing what happens. We use lasers to investigate what is occurring at the surface; to probe the properties of interfaces and porous materials; and to initiate chemical reactions and physical changes in interfaces and porous materials.

The red image on the left is a photo I took of an ultrafast dye laser that I used at NIST. The green image in the middle is a photo of a femtosecond Ti:sapphire of the type I used in Birmingham and at UVa. The image on the right is of the nanosecond Nd:YAG laser we use for ablation at WCU.

Photochemical & Chemical Modification of Si and Porous Si

UV/Vis of V2O5 Etch

The stoichiometry of Si electroless etching in V2O5 + HF solutions

Angew. Chem. Int. Ed. Eng., 52, 6731-6734 (2013)

Si Nanowires

The stoichiometry of metal assisted etching of Si in V2O5 + HF and HOOH + HF solutions

Electrochim. Acta, 158, 219–228 (2015)

Electron transfer

Electron transfer during metal-assisted and stain etching of silicon
Semicond. Sci. Technol. 31, 014002 (2016)

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 of porous 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 photochemical reactions involved. An example can be found here in J. Amer. Chem. Soc.

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 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. We have demonstrated that several ions work well, including Fe(III), Ce(IV) and IrCl62- and we now have a quantitative understanding of charge transfer in terms of Marcus theory. The V(V) ion has been used to form uniform films that can be as much as 20 µm thick and well as por-Si powder in collaboration with Vesta Ceramics.

As described below, we make macroporous silicon (porous silicon with very large pores) by etching pillar-covered Si substrates in alkaline solutions.

For more on porous silicon click here.

Pillar Formation & Modification

Etched Hexagon

Hexagonal macropore etched into pillar-covered Si crystal

Laser irradiation of semicondutors and metals, under the appropriate conditions can lead to the spontaneous formation of conical structures. When made with a femtosecond laser, these pillars 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 larger, up to 100 µm or more and a few micrometers at their tip. We have shown that we can make such pillars in silicon, germanium as well as titanium and a number of other metals including Zn, Sn and Ni.
We have used alkaline solutions (concentrated KOH or tetramethylammonium hydroxide, TMAH) to etch silicon pillars. Short etching times produce sharpended pillars. When the pillars are overetched, they disappear leaving behind macropores that are several micrometers wide, such as the hexagon shown left.

ZnO nanorods

ZnO nanorods grown on a Zn laser ablation pillar

More on pillars and macropores can be found here.

Anodic Titania Nanotubes & Porous Alumina

Nanoscepters

NH4AlF4 nanoscepters

This project involves electrochemically etching Ti or Al to created arrays of nanotubes or pores while simultaneously oxidizing the metal to its oxide (titania, TiO2, or alumina, Al2O3). Read more about it here.

TiO2 nanotubes

Dynamics of Adsorption and Desorption


I have long studied the simplest of surface chemical reactions, the adsorption and thermal desorption of small molecules from surfaces, particularly hydrogen on silicon. I have also reviewed stimulated desorption of hydrogen from silicon. While this work has laid the foundation for much of my research, currently these are not the types of studies that I'm performing in my lab in West Chester. Rather they are part of what of do when I work with, for instance, Eckart Hasselbrink in Essen, Germany.
Read more about the my studies of surface dynamics here.

Solidification Driven Extrusion (Nanospikes)

While making silicon and germanium pillars, we noticed that nanoscales spikes form atop the pillars. We subsequently showed that the same physics that is behind this phenomenon is also active in your freezer and can result in the formation of centimeter long ice spikes. Read more about this here.

Ultrafast Surface Photochemistry in the VUV

This was a project I worked on while at the University of Birmingham that involves the use of femtosecond pulsed lasers to create vacuum ultraviolet photons via high harmonic generation.
Read more about it here.

Selected Recent Publications:

For a nearly full list of publications click here.


Textbooks

K. W. Kolasinski, Physical Chemistry: How Chemistry Works. (John Wiley & Sons, Chichester, to be published 2016)

Kurt W. Kolasinski, Surface Science: Foundations of Catalysis and Nanoscience, 3rd Edition ( John Wiley & Sons , Chichester, 2012).

Accompanying website for the book, including the figures in pdf format, supplemental material and exercises.


For further information on related topics, try these sites:

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