The study of condensed matter using optical techniques, where photons
act as both probe and signal, has a long history. It is only recently,
however, that the extraction of surface and interface information, with
submonolayer resolution, has been shown to be possible using optical
techniques (where "optical" applies to electromagnetic radiation in and
around the visible region of the spectrum). This book describes these
"epioptic" techniques, which have now been quite widely applied to
semiconductor surfaces and interfaces. Particular emphasis in the book
is placed on recent studies of submonolayer growth on well-characterised
semiconductor surfaces, many of which have arisen from CEC DGJGII ESPRIT
Basic Research Action No. 3177 "EPIOPTIC", and CEU DGIII ESPRIT Basic
Research Action No. 6878 "EASI". Techniques using other areas of the
spectrum such as the infra-red region (IR spectroscopy, in its various
surface configurations), and the x-ray region (surface x-ray
diffraction, x-ray standing wave), are omitted. The optical techniques
described use simple lamp or small laser sources and are thus, in
principle, easily accessible. Epioptic probes can provide new
information on solid-gas, solid-liquid and liquid-liquid interfaces.
They are particularly suited to growth monitoring. Emerging process
technologies for fabricating submicron and nanoscale semiconductor
devices and novel multilayer materials, whether based on silicon or
compound semiconductors, all require extremely precise control of growth
at surfaces. In situ, non-destructive, real-time monitoring and
characterisation of surfaces under growth conditions is needed for
further progress. Both atomic scale resolution, and non-destructive
characterisation of buried structures, are required.
