Epitaxial phase change materials
GST on GaSb
Phase change materials such as Ge2Sb2Te5 (GST) are currently investigated as a replacement for FLASH memory and even as (PC)RAM. The reason is their fast switching speed and good scalability. Despite their widespread use e.g. in rewritable DVD technology, the detailed mechanism of the transition between the crystalline and the amorphous state is not yet understood.
We grow epitaxial layers of GST and analyze their structure using in situ x-ray diffraction. The phase transition is induced either by annealing or by applying a high-power laser pulse. By synthesizing MBE purity material with epitaxy-induced long-range order, we intend to clarify the role of GST's intrinsic vacancies in the switching process.

