The metal-induced lateral crystallization (MILC) of an amorphous Ge (a-Ge) thin film using Ni nanoparticles (NPs) was investigated. Ni-NPs were formed and evenly distributed onto a 30 nm thick a-Ge film by cage-shaped protein. After complete elimination of protein shell, crystal growth was performed at 400 degrees C. Raman spectra and electron backscatter diffraction (EBSD) studies revealed that a poly-Ge film with a maximum grain size approximately 1 mu m was successfully formed. The Ni contamination in the poly-Ge film was reduced by more than one order of magnitude compared with that in the case of a conventional MILC process. (C) 2011 Elsevier B.V. All rights reserved.