Indentation-induced crystallization and phase transformation of amorphous germanium

It has been known for about 15 years that when a Vickers indenter is loaded on to a crystalline semiconductor, such as silicon, a semiconductor to metallic phase transition occurs during indenter loading and on removal of the indenter the material within the residual indentation becomes amorphous. Here we report a completely opposite effect: when a Berkovich or Vickers diamond indenter is loaded onto a submicrometer thick film of amorphous germanium, it crystallizes and undergoes structural phase transitions. These observations are based on our transmission electron microscopy and Raman scattering investigations, which have been described. It has also been shown that the indentation-induced crystallization and phase transitions occur close to the indenter tip, where the plastic strains are the highest. (C) 2004 American Institute of Physics.