Bradby, J. E.Williams, J. S.Wong-Leung, JenniferSwain, M. V.Munroe, P.2015-10-212015-10-210003-6951http://hdl.handle.net/1885/15992The deformation mechanisms of crystalline (100) Ge were studied using nanoindentation, cross sectional transmission electron microscopy (XTEM) and Raman microspectroscopy. For a wide range of indentation conditions using both spherical and pointed indenters, multiple discontinuities were found in the force–displacement curves on loading, but no discontinuities were found on unloading. Raman microspectroscopy, measured from samples which had plastically deformed on loading, showed a spectrum shift from that in pristine Ge, suggesting only residual strain. No evidence (such as extra Raman bands) was found to suggest that any pressure-induced phase transformations had occurred, despite the fact that the material had undergone severe plastic deformation.Selected area diffraction pattern studies of the mechanically damaged regions also confirmed the absence of additional phases. Moreover, XTEM showed that, at low loads, plastic deformation occurs by twinning and dislocation motion. This indicates that the hardness of Gemeasured by indentation is not primarily dominated by phase transformation, rather by the nucleation and propagation of twin bands and/or dislocations.http://www.sherpa.ac.uk/romeo/issn/0003-6951..."Publishers version/PDF may be used on author's personal website, institutional website or institutional repository" from SHERPA/RoMEO site (as at 21/10/15). Copyright 2002 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters and may be found at https://doi.org/10.1063/1.1469660Keywords: Cross-sectional transmission electron microscopy; Damaged region; Deformation mechanism; Dislocation motion; Force-displacement curves; Indenters; Low load; Phase transformation; Pressure-induced phase transformations; Raman bands; Raman microspectroscopy2002-04-1510.1063/1.14696602016-02-24