Size-Dependent Surface-Induced Heterogeneous Nucleation Driven Phase-Change in Ge2Sb2Te5 Nanowires

作者：Lee Se Ho; Jung Yeonwoong; Agarwal Ritesh^*

来源：Nano Letters, 2008, 8(10): 3303-3309.

DOI：10.1021/nl801698h

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.

• 出版日期2008-10