Dresden 2014 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 37: Posters: Plasmonics, Electronic Structure and Spin-Orbit Interaction, Semiconductor and Insulator Surfaces, Nanostructures
O 37.45: Poster
Dienstag, 1. April 2014, 18:30–22:00, P2
Scanning tunneling microscopy investigation of the phase change material Ge2Sb2Te5 — •Jens Kellner1, Christian Pauly1, Marcus Liebmann1, Alessandro Giussani2, Volker Deringer3, Raffaella Calarco2, Richard Dronskowski3, and Markus Morgenstern1 — 1II. Physikalisches Institut B, RWTH Aachen University and JARA-FIT, Germany — 2Paul Drude Institut für Festkörpelektronik, Berlin, Germany — 3Institute of Inorganic Chemistry, RWTH Aachen University, Germany
We investigated the phase change material GST-225. Despite the fact that GST is already commercially used, there is still no complete theory which can explain the ultra fast switching speed, the strong contrast and the high endurance of the Ge-Sb-Te alloys. One ingredient of such a theory is an atomic scale understanding of the electronic properties of GST.
Scanning tunneling microscopy (STM) measurements are used to achieve atomic resolution on metastable cubic GST. The STM data show the regular hexagonal Te lattice, which exhibits an additional irregular contrast. Comparison with DFT calculations reveals that subsurface defects create such contrast. For different subsurface arrangements of Ge, Sb and vacancies, simulated STM images show good agreement with experimental data. Scanning tunneling spectroscopy (STS) data revealed p-type doping and a band gap of 0.4 eV.