Free-running Sn precipitates: an efficient phase separation mechanism for metastable Ge_1-xSn_x epilayers.

ABSTRACT: The revival of interest in Ge_1-xSn_x alloys with x ≥ 10% is mainly owed to the recent demonstration of optical gain in this group-IV heterosystem. Yet, Ge and Sn are immiscible over about 98% of the composition range, which renders epilayers based on this material system inherently metastable. Here, we address the temperature stability of pseudomorphic Ge_1-xSn_x films grown by molecular beam epitaxy. Both the growth temperature dependence and the influence of post-growth annealing steps were investigated. In either case we observe that the decomposition of epilayers with Sn concentrations of around 10% sets in above ≈230 °C, the eutectic temperature of the Ge/Sn system. Time-resolved in-situ annealing experiments in a scanning electron microscope r

SUBMITTER: Groiss H 

PROVIDER: S-EPMC5700949 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature