Although there is no Surface Canada meeting in 1994, there will be relevant symposia at the CSC meeting in Winnipeg - see elsewhere in this newsletter. The division is finalizing plans for the Surface Canada meeting in 1995 - most probably in Waterloo. It is hope that Sydney Davison (U Waterloo) will organize a special surface science symposium for the journal "Progress in Surface Science" and that the two meetings will be held in the same week. This will also fit in nicely with the CSC meeting in Guelph; it will be a good year for surface science.
As past chair, my duty includes fingering people to agree to stand for election to the position of vice-chair. I will also be trying to determine the criteria and conditions for an award in the area of surface science. I am also considering designs for division tee-shirts. I need some help with this one - suggestions for designs, logos, etc would be much appreciated (how about "We don't just scratch the Surface"!).
I would like to thank the outgoing Secretary/Treasurer Tom Ellis for all his work for the division. This job is the executive's most onerous one, and Tom has done a wonderful job. Welcome to Leo Lau, who is going to take over this position for the next three years. Now I can bow out and not have to write any more of these pieces. Hope you all have a good 1994.
Love, Dave Harrington
1994 is likely to be another challenging year for those of us in the business of science, and business is really the operative word in this sentence. In the government laboratory where I work, we have been keenly aware, for about the past three years, of the complex relationship between economic productivity and scientific freedom. We would like to believe that scientific freedom results in economic productivity, and it certainly is true that science has fed industry. History also shows that scientists have only enjoyed the license to select their own topics of investigation during times of prosperity, especially if the cost of conducting the the science is high. During this decade and the next, we may witness a long-anticipated chronic slowdown in the economy, which comes as something of a shock to those of us who were educated and found our first jobs in a period of unprecedented growth. We are all concerned for the future employment prospects of our children, our graduate students and even ourselves!
Luckily, surface science is one of those areas which offers both exciting intellectual challenge and genuine industrial opportunity, with applications in catalysis, corrosion, wear, packaging, optics and electronics, to name just a few. The Surface Science Division has recognized the essential need to "pay the piper", and we can point to our own finances as evidence of our fiscal awareness. Thanks to the prudent business acumen of former chairmen, the Division operates relatively free of financial strain, to the point where we can consider setting up a trust fund to provide for a continuing award series, in addition to our prestigious Hobson Award. Past Surface Canada conferences have always sought participation from individuals involved in industrial applications of surface science. The meetings we are sponsoring for 1994 are no different, and we hope all of you will be able to participate in the Symposia on Surface and Solid-State Chemistry which are being held during the CSC Meeting in Winnipeg next May. Members of the Surface Science Division are heavily involved in organizing the sessions, including one on Applied Surface Science for Industry which is being organized by Bill Hocking and Stewart McIntyre. These and other activities are described in the following newsletter.
All in all, we think we can "throw our shoulders to the plough" to meet the economic challenges of the present era, and enjoy ourselves while we're at it! I wish you all an enriching 1994 and I hope to see many of you in Winnipeg.
Yours sincerely,
Jenny Jackman
Obviously scanning probe microscopy was not the only subject of the meeting. Many talks and posters were presented in the areas including electrochemical interfaces, oxidation and corrosion, surface modification of materials by plasmas and particle beams, soft surfaces, semiconductor interfaces and surfaces, and mass spectroscopy of surfaces.
The Hobson Award winner in this meeting was G.W. Anderson from UWO. A personal profile of Anderson will appear in the next newsletter.
(by Leo Lau)
The conference had a very strong surface science component with 8 oral and 19 posters directly in our field and many others of interest. Averbach (Argonne) and Garrison (Penn St) each discussed results of recent molecular dynamics calculations of low energy ions ( few eV to 10s of keV) interacting with surfaces. Structure of surfaces and overlayers was the common theme to presentations by O'Connor (Newcastle), Varga (Wien) and Sack (Rutgers). Charge exchange processes, always a dominate theme at this conference, was represented at the surface by talks by Narmann (Odense) and Auth (Munster). The last of the oral presentations was by Kalish (Technion) who discussed ion-induced mixing of buried interfaces. The many posters represented just as broad spectrum of activities and material systems.
These contributions, together with talks which ranged from channeling of GeV ions to plasmon excitation in an electron gas to the amorphization of semiconductors, made for a conference filled with stimulating 'corridor' discussions.
A big thanks to the Division for helping to make it happen.
(by Willy Lennard and Tom Jackman)
Dr. J. Polanyi (Toronto) opened the Symposium with a description of recent experiments that provided the first direct evidence of photoinduced charge transfer from metal surfaces to adsorbates, and how this transfer can lead to molecular dissociation and secondary reaction pathways in adsorbed multilayers. This was followed by the presentation of Dr. Ph. Avouris (IBM/Yorktown), who discussed how scanning tunneling microscopy can be used to probe, on an atomic scale, the chemical and physical properties of metal and semiconductor surfaces. He also provided examples of molecular fragmentations that were induced by the electron current passing between the STM tip and the surface, providing a mechanism for the control of surface processes on Angstrom length scales. Dr. M. Morin (Ottawa) reported on his studies of vibrational energy relaxation processes on hydrogen terminated Si(111) surfaces, and how sum frequency generation spectroscopy can be used to directly probe the redistribution of energy on these surfaces. Dr. J. Yates (Pittsburgh) presented the results of his infrared absorption and angularly resolved electron stimulated desorption studies that showed the site selectivity for O2/Pt and CO/Pt adsorptions; this information provided important clues for the interpretation of the observed reaction rates of coadsorbates on Pt surfaces. Dr. S. Kaliaguine (Laval) discussed measurements of the N1s binding energy of chemisorbed pyrrole as a sensor of the Lewis basicity of cation exchange zeolites, and presented the correlations between XPS results, catalytic activity, and the selectivity of basic zeolites as catalysts in several reactions. Dr. P. McBreen (Laval) described the use of infrared spectroscopy to investigate the surface chemistry of esters and related compounds on Ni(111). He also reported on the sensitivity of the adsorption geometries to the electronic structure of the surface by using Cu and Pd substrates. Dr. L. Sanche (Sherbrooke) provided a description of the mechanisms of energy and charge transfer that can be induced by exposure of surfaces and adsorbates to low-energy electron beams; specific examples included the rare gas solids and the interaction of atomic and molecular targets with the excited states of these substrates.
In addition to the above Invited presentations, two excellent student presentations were made. H. Donsig (Texas A&M) described her work on the desorption of alcohols and alkanes from surfaces during laser excitation of adsorbates, while M. Lam (Dalhousie) described her theoretical investigations of the dehydrogenation of ethane to acetylene on Ni(111) surfaces.
On behalf of myself and Dr. M. Poirier (CANMET), we would like to thank all of the participants, all of the attendants, and all of the sponsors for their contributions to the success of this Symposium.
For the description of a heterojunction formation, the most critical parameters are the interfacial chemistry and strain. These, in turn, determine the atomic diffusion and segregation during growth and annealing. Such a picture was clearly conveyed by Jean-Marc Baribeau (Institute for Microstructural Sciences, NRC) who showed many recent results on some MBE grown Si-Ge heterostructures.
The main applications of heterostructures are undoubtedly microelectronics and optoelectronics. Here the correlations between electronic and geometric structures are most relevant. This was elaborated by Scott Chamber (Pacific Northwest Lab., Battelle) and Tony van Buren (Physics, UBC). Scott used XPS to measure the valence band offset of Si/GaAs as the heterojunction evolved, and the band bending of such structures as a function of As-doping. These electrical properties were correlated to geometric structural data obtained by photoelectron and Auger electron diffraction, LEED and AFM. The theme of the symposium was then further expanded by Tony who showed some interesting synchrotron radiation XPS and absorption data on porous Si. The electronic structures thus obtained were used to support the quantum confinement model for the anomalous optical properties of porous Si.
Magnetic properties of materials are rather mysterious to many of us. In the symposium, S.S.P. Parkin (IBM, Almaden) showed further that when ultrathin metallic magnetic structures are put together, a giant magnetoresistance may be exhibited. Ultrathin Co/Cu multilayers on Si(100) were used as a typical example in this invited talk. The characteristic interfacial layer thickness was shown to be about 2 . The origin of the anomalous magnetic properties was attributed to scattering of spin-up and spin-down electrons of the ultrathin heterostructures.
ISW is complemented by provincial funding via the Ontario Centre for Materials Research (OCMR), providing a second surface and materials science laboratory in the newly constructed Western Science Centre.
In summary, the research program focuses on:
SSW functions as a consulting laboratory to industry in many aspects of material surface development and analysis. The laboratory also serves the needs of the research community within the University, in addition to carrying out its own research and development projects. SSW functions as a training ground for young scientists and engineers through graduate research programs operated under the faculties of science and engineering.
SSW laboratories and offices cover over 700 m2 of the ground floor of the Laurene O. Paterson Building, also called the Western Science Centre. Its instrumental facilities for surface analysis are the most comprehensive of any university-based laboratory in North America. Some of these are summarized as follows:
Microscopy: Optical microscopy, SEM, AFM, and scanning Auger (PHI-600).
XPS: Surface Science Laboratories Model SSX-100 with several peripheral chambers for in situ surface reactions.
SIMS: Modified Cameca 3-f Model dynamic SIMS and a UHV static SIMS.
Raman: Dilor OMARS89 Raman microprobe.
Electrochemical analysis facilities: DC and AC meters, and microprobe-electrodes.
Polymer surface modification facilities: Plasma and UV/ozone systems.
Thin film deposition facilities: Plasma CVD and sputtering systems.
SSW is operated under a multi-user policy. The scientific staff of 12 has over 90 years experience in surface science and related fields, and is trained to assist external users to obtain their research results at SSW. Access to SSW's services is arranged through the Manager of Scientific Operations (Mr. Ross Davidson, Tel: 519-661-2173).
Electrochemistry of Materials and Films (D.W. Shoesmith and J.J. Noel/AECL)
Invited: D. Wiesler
Spectroscopy of Surfaces (S. Sunder/AECL)
Invited: J.C. Polanyi, M. Moskovits, P. Norton, C. Colmenares
Bill Hocking is pleased to answer/redirect any enquiries about these symposia. He can be reached by tel: 204-753-2311, fax: 204-753-8404, and mail: AECL Research, Whiteshell Laboratories, Pinawa, Manitoba, Canada R0E 1L0.
**Bill is still accepting abstracts!
Dr. Christopher Hunt, Division of Materials metrology, National Physical Laboratory, Teddington, Middlesex, UK TW11 0LW Tel: 011-44-81-943-7027; Fax: 943-2989
Sometime in 1994 Biomaterials applications of surface science techniques - a workshop organized by Dr. Rana Sodhi, Centre for Biomaterials, University of Toronto; Tel: 416-978-5381.
Our fundamental work focuses on the interface formation and growth dynamics of III-V heterostructures. We study phase separation kinetics of metastable or instable monolayer deposits, which are dominated by nucleation, ripening and coalescence phenomena. A common topic is the relevance of self-similarity of the cluster size distributions and scaling behaviour of the growth laws. Most recently we test several systems which should violate that concept due to microscopic processes of single clusters, such as shape oscillations for In on InP (001).
Such studies are the natural extension of my previous work over the past 8 years. I started at the max-Planck-Institute for Nuclear Physics in Heidelberg, where I learned to apply ion beam methods to analyze questions in solid state physics. As a PDF at Bell Laboratories in Murray Hill (1986-88) the emphasis was shifted toward thin film growth in group IV heterosystems. We investigated the breakdown of uniform layers during post-deposition annealing and found that Ostwald ripening described these effects very well. At the Research Centre in Julich, where I held a tenured staff position form 1988 to 1990, I investigated the role of cluster formation and surface diffusion in these processes, resulting in reliable surface diffusion data for Ge on a strained Ge/Si substrate. When I came to the Physics Department of the University of Western Ontario late 1990 (thanks to Tom Jackman who lured me away from relocating to the US) we started to work on III-V substrates. The interest in this direction had emerged during a sabbatical stay at Bell Laboratories during 1989 when we saw that a much wider range of microscopic processes interact with the growth of clusters and that the coalescence growth range becomes easier accessible.
I kept my contacts to the group IV research (and to Bell Laboratories) alive over the last few years and with new contacts I made in the meantime at Northern Telecom it became interesting to follow up a few topics on silicon substrates, one being the formation of silicide layers and buried silicide layers, which we pursue with a Strategic NSERC program, and one being the formation of the Ge/Si interface which we pursue with funds from the OCMR.
Liji obtained his BSc in Solid State Physics and Materials Science in 85, MSc in Materials Science in 86, and PhD in Metal Physics in 88, all from Tsinghua University in Beijing (the MIT in China). After his PhD graduation, he was recruited as a Faculty member in Materials Science and Engineering at the same university. Since 1990, he has been working in my research group initially as a postdoctoral fellow and later as a research associate. In the past three years, he has made many contributions to my research projects on ion bombardment of diamond, ultrashallow doping, and surface passivation of semiconductors. In this period, he has also collaborated closely with Peter Schultz on defect studies using positron annihilation spectroscopy, with Ian Mitchell on ion beam analyses, and with Sid Ingrey and Dolf Landheer on passivation of semiconductors.
Liji certainly has an outstanding research calibre. He earned an Excellent Student Award from the Tsinghua University in 1985, a Graduate Student Award from the Materials Research Society in 1988, and a Young Researcher Prize from the Fok Ying Tung Education Foundation in 1989. At an age of 30, he has already published about 50 articles, one book chapter (Topic: New directions in modern sciences), and edited two books ("Thin Films and Beam-Solid Interactions" (Elsevier, 1991); "Electronic materials/Frontiers of Materials Research" (Elsevier, 1991)).
Liji's wife came to Canada two years ago and is about to finish her Master degree in Library and Information Sciences. Both of them spend most of their time at work. Otherwise, they listen to music and do some leisure reading. They are both quiet yet very friendly people.
