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SSL Seminar Series 2001 No. 10
Title: RHEED Rocking Curves and Determination of Surface Structures
Speaker: Dr Nikolai Yakovlev (IMRE, Singapore)
Date: 25th April 2001
Time: 5:00-6:00pm
Venue: Physics Resource Room S13, 02-16
Abstract
RHEED is reflection high energy electron diffraction. With electron
energy in the range of 3 to 30 keV, diffraction images from crystal
surfaces can be obtained at incident angles of several degrees with
respect to the surface. Thus this technique is widely used to study
surfaces during film growth in vacuum. Analysis of atomic structure
of the surface is done measuring rocking curves, that are dependences
of diffracted intensity on the incident angle, and comparing them
with calculated curves. The presentation will give a brief introduction
to RHEED calculations using dynamical theory developed at the University
of Leicester [1]. Then the Marquardt algorithm of adjusting atomic
positions to fit the rocking curves [2] will be discussed. It will
be shown how the RHEED anaylsis was applied to Si, CaF2 and MnF2 surfaces
[3].
[1] P.A.Maksym, J.L.Beeby, Surf.Sci. v.110, 423 (1981),
v.140, 77 (1984)
[2] U.Korte, G.Meyer-Ehmsen, Surf.Sci. v.271, 616 (1992)
[3] N.L.Yakovlev, A.G.Banshchikov, M.M.Moisseeva, N.S.Sokolov, J.L.Beeby,
P.A.Maksym, Surf.Interface Anal. v.28, 264 (1999)
About the speaker
Dr. Nikolai Yakovlev obtained his MSc degree at Leningrad Polytechnic
Institute and PhD degree at Ioffe Physico-Technical Institute, Russia.
Then he worked as a researcher at the Ioffe Institute in the field
of epitaxial insulators. During recent years he collaborated in molecular
beam epitaxy with Rensselaer Polytechnic Institute, USA, in optical
studies of fluorides with the University of Georgia, USA, in RHEED
with the University of Leicester, UK, and Nagoya Univeristy, Japan.
At present, he works on SIMS at the Institute of Materials Research
and Engineering, NUS. |
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