Microstructural comparison of material damage in GaAs caused by Berkovich and wedge nanoindentation and nanoscratching

Nanoindentations and nanoscratches in GaAs under Berkovich and 60° wedge indenters were investigated via transmission electron microscopy. Dislocations, twins and slip bands are convergent under the Berkovich indenter, whereas they are only divergent under the 60° wedge. This difference is explained in terms of crystallography and geometry. Median cracks were created under the wedge indenter although only diverging bands are observed. Finally, twinning was found to be the main deformation process occurring during indentation, whereas only slip bands and perfect dislocations are observed during scratching.