surface x-ray diffraction in
transmission geometry
Hiroo Tajiri,a Osami Sakata,a and Toshio Takahashib
aMaterials Science Division, Japan Synchrotron
Radiation Research Institute, SPring-8, 1-1-1 Mikazuki-cho, Sayo, Hyogo
679-5198, Japan; bInstitute
for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi,
Chiba 277-8581, Japan,
(tajiri@spring8.or.jp)
Surface x-ray
diffraction technique combined with 3rd generation synchrotron
source and well-established surface x-ray diffractometer now becomes one of
reliable tools to solve surface crystal structure. However, it does not mean we
can easily obtain not only atomic structure but also electron density
distribution on surface. Demands for ÔpreciseÕ structure analyses become severe
according to complexity in surface system that surface scientists are
interested in.
We focus
attention on transmission x-ray diffraction to meet such demands. Although a
surface structure analysis by transmission x-ray diffraction was performed
successfully more than ten years ago[1], No further experimental report in
transmission geometry has followed because of instrumental problems and its
limits in applications. Now, we can easily access two-dimentional detectors
such as an image plate and an x-ray CCD camera with large diameter. The
progress in the x-ray detectors makes us possible to investigate large areas in
reciprocal space simultaneously as electron diffraction techniques. Therefore,
it is worth studying the capabilities of transmission x-ray diffraction in
surface structure analysis.
We performed
preliminary experiments in air with using chemically etched Si(111) thin wafers
and image plates. They provided us with precise intensities along a crystal
truncation rod. Further progress in the method with an ultra-high vacuum
condition will also be discussed.
References
1
Takahashi, T.,
Nakatani, S., Okamoto, N., Ishikawa, T., Kikuta, S. (1991) Surf. Sci. 242, 54