Micro-Raman mapping and analysis of indentation-induced phase transformations in germanium

Jae Il Jang, M. J. Lance, Songqing Wen, J. J. Huening, R. J. Nemanich, G. M. Pharr

Research output: Contribution to journalConference articlepeer-review

2 Scopus citations

Abstract

Although it has been confirmed by diamond anvil cell experiments that germanium transforms under hydrostatic pressure from the normal diamond cubic phase (Ge-I) to the metallic β-tin phase (Ge-II) and re-transforms to Ge-III (ST12 structure) or Ge-IV (BC8 structure) during release of the pressure, there are still controversies about whether the same transformations occur during nanoindentation. Here, we present new evidence of indentation-induced phase transformations in germanium. Nanoindentation experiments were performed on a (100) Ge single crystal using two triangular pyramidal indenters with different tip angles - the common Berkovich and the sharper cube-corner. Although the indentation load-displacement curves do not show any of the characteristics of phase transformation that are well-known for silicon, micro-Raman spectroscopy in conjunction with scanning electron microscopy reveals that phase transformations to amorphous and metastable crystalline phases do indeed occur. However, the transformations are observed reproducibly only for the cube-corner indenter.

Original languageEnglish
Article numberR10.9/T6.9
Pages (from-to)291-296
Number of pages6
JournalMaterials Research Society Symposium Proceedings
Volume841
StatePublished - 2005
Event2004 MRS Fall Meeting - Boston, MA, United States
Duration: Nov 29 2004Dec 3 2004

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