Speaker
Description
Extending ellipsometry to the vacuum-ultraviolet spectral region, i.e., photon energies larger than 6.5 eV, is not only demanding in terms of the instrumentation but also with regard to the mathematical modelling of the measured data in order to obtain a physical interpretation in terms of the dielectric function or the optical constants of a material. In particular the extreme surface sensitivity of the measurement at these energies makes this a valuable tool for investigation of surfaces and thin film materials.
In this contribution we present results on experimental investigations of the optical properties of bulk semiconductors, Si, Ge and SiC, and thin solid films (graphene and h-BN) grown on them.
The ellipsometric angles of these material systems have been measured at different incidence angles and photon energies ranging from 1.6 eV up to 25 eV, in order to characterise the full electronic structure.
In a subsequent step, we extracted the optical constants and the dielectric function of the materials using a fitting method and a methodology which is compliant with international metrological practice.
