Reflectance anisotropies of polycrystalline Ce1?x Gdx O2?x?2 /Si(001) interfaces
Sprache des Titels:
Englisch
Original Kurzfassung:
Ce1???Gd??O2????2 thin films were deposited by spin coating on oxidized Si(001) substrates. Two strain regimes are
observed by ??? Raman spectroscopy: for ?? < 0.1 the films are tensile strained, whereas a strain component of
the wave number shift of ?71.2?? cm?1 compensates with a 32.6?? cm?1 bond component for ?? > 0.1. Reflectance
anisotropy spectroscopy (RAS) measurements were carried out on these films in which interface-related optical
anisotropies signatures appearing in the 1.5 eV to 3.6 eV photon energy range are found dependent on the
incorporation of Gd in the lattice. To explain the observed RAS signatures with a complex reflectance threephase
model, we resorted to spectroscopic ellipsometry (SE) to retrieve the interface optical anisotropies (IOA)
related to the changes in refractive index, < ???? >, between interface formed by both the oxidized Si(001) and
polycrystalline CeO2:Gd films, and to assess the CeO2 energy gap variation from 3.2 to 2.8 eV in the 0 < ?? <
0.4 composition range. This study renders the combination of RAS, Raman, and SE versatile tools to optimize
the growth parameters during the fabrication of devices based on polycrystalline CeO2 on a quantitative basis.
Forschungs-