Anomalous nucleation of crystals within amorphous germanium nanowires during thermal annealing

In this work, germanium nanowires rendered fully amorphous via xenon ion irradiation have been annealed within a transmission electron microscope to induce crystallization. During annealing crystallites appeared in some whilst others remained amorphous. Remarkably, even when nucleation occurred, large sections of the though few embedded phase were formed at minimum 200 °C above temperature for epitaxial growth and 100 random bulk germanium. Furthermore, presence was observed depend on diameter nanowire. Indeed, formation occurred higher thin compared with thicker ones. Additionally, 55 nm made entirely crystalline performed normally required crystallization (i.e. 500 °C). It is proposed that oxygen atoms hinder both crystallites. as must reach size survive grow nanowires, instability may also play limited role thinnest nanowires.