title: Size-dependent surface-induced heterogeneous nucleation driven phase-change in Ge2Sb2Te5 nanowires.
abstract: By combining electron microscopy and size-dependent electrical measurements, we demonstrate surface-induced heterogeneous nucleation-dominant mechanism for recrystallization of amorphous phase-change Ge2Sb2Te5 nanowires. Heterogeneous nucleation theory quantitatively predicts the nucleation rates that vary by 5 orders of magnitude from 190 to 20 nm lengthscales. Our work demonstrates that increasing the surface-to-volume ratio of nanowires has two effects: lowering of the activation energy barrier due to phonon instability and providing nucleation sites for recrystallization. The systematic study of the effect of surface in phase-change behavior is critical for understanding nanoscale phase-transitions and design of nonvolatile memory devices.
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Se-Ho
authors.initials: SH
authors.lastname: Lee
authors.forename: Yeonwoong
authors.initials: Y
authors.lastname: Jung
authors.forename: Ritesh
authors.initials: R
authors.lastname: Agarwal