Temperature-dependent high-resolution X-ray photoelectron spectroscopic study on Ge1Sb2Te4

• Published in: Thin solid films Vol. 518; no. 20; pp. 5670 - 5672
• Main Authors: LEE, Y. M, JUNG, M.-C, SHIN, H. J, KIM, K, SONG, S. A, JEONG, H. S, KO, C, HAN, M
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Amsterdam Elsevier 02-08-2010
• Subjects: Annealing; Antimony; Boundary element method; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Germanium; Mathematical analysis; Physics; Spectra; Surface and interface electron states; Surface states, band structure, electron density of states; Thin films; X-rays; Valence bands; Amorphous thin film; Annealing temperature; PRAM; Photoelectron spectroscopy; High vacuum; Thin films; Te; Temperature effects; Shallow level; Thermal annealing; Antimony tellurides; Synchrotron radiation; Temperature dependence; Antimony; Core levels; HR-XPS; Sb; Electronic structure; Binding energy; Germanium tellurides; Core-level spectra; Germanium; Ge; X-ray photoelectron spectra
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2009.10.028

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 250AC. 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 ~12eV BE, and a decrease, at ~1.5 and ~4.5eV BE. The energy resolution employed in this study was about 150meV.