Cu nanoparticle induced crystallization of amorphous Ge film using ferritin

The metal-induced lateral crystallization (MILC) of an amorphous Ge (a-Ge) thin film using Cu nanoparticles (NPs) was investigated. Cu-NPs were formed by a cage-shaped protein. After complete elimination of protein shell, crystal growth was performed at 300°C. Raman spectra and TEM studies revealed that a poly-Ge film was formed at low temperature. The crystallization temperature depends on the metal-NP because of the different activation energy for crystallizing the a-Ge into the poly-Ge. As the result, the Cu-NP MILC method is more efficient for the low temperature crystallization and the low metal contamination.