Interfacial intermixing of Ge/Si core-shell nanowires by thermal annealing

Ge/Si core-shell nanowires (NWs) have huge potential for the realization of high mobility channels in NW field-effect transistors. Thermal annealing is a crucial process for optimizing electrical properties in many applications because it affects the NWs' morphology, crystallinity, dopant activation, and interface intermixing. In this study, we investigated the structural transformation of core-shell NWs at the interface and their thermal stability. The intermixing of Ge and Si atoms at the interface closely depends on, and is enhanced by, the temperature and pressure during annealing, while no intermixing occurred at pressures lower than 6 × 10^-6 Pa.