Temperature-dependent high-resolution X-ray photoelectron spectroscopic study on Ge1Sb2Te4
Journal
THIN SOLID FILMS
Date
2010.09.26
Abstract
Oxygen-free and amorphous Ge1Sb2Te4 thin film was obtained in
an ultra-high vacuum and then annealed in situ to the stable-
phase temperature. High-resolution X-ray photoelectron
spectroscopy using synchrotron radiation was performed on the
film at the different annealing temperatures of 100, 130,
150, 180, and 250 ?C. The Te 4d, Sb 4d, and Ge 3d shallow
core levels as well as the valence-band spectra were
acquired. In the shallow core-level spectra, we observed
distinguishable changes in the Sb 4d and Ge 3d levels as the
film phase changed. As the temperature increased, a higher
binding-energy (BE) component appeared at the Sb 4d level,
the intensity of the component increased, and the spin-orbit
split feature was enhanced at the Ge 3d level. In the valence-
band spectra, a slight increase was observed at 0?1, ~3, ~9,
and ~12 eV BE, and a decrease, at ~1.5 and ~4.5 eV BE. The
energy resolution employed in this study was about 150 meV.