A study was made of polarity-induced changes in the nano-indentation response of GaAs{111}. The nano-indentations were made using a large range of loads, Fmax, of between 0.2 and 50mN at room temperature on {111} faces of A (Ga) or B (As) character. The loading-unloading curves were compared, with particular attention being paid to pop-in events and hardness values. Transmission electron microscopy was used to observe the nano-indentation structures generated at the 2 polar surfaces. The size of the dense plastic zone which was generated around the indentation site was found to increase linearly, with √Fmax, similarly for both polar surfaces. The indentation rosettes had threefold symmetry, with arms being developed along <110> directions parallel to the surface. The sizes were very close for both polar surfaces, and for the entire load range. For the A-polar face, the rosette arms were made up of 2 arms: a long arm (α dislocations) and a short arm (β dislocations). At the B surface, only the long arm (β dislocations) was formed. Micro-twinning was observed only for the A-polar face, as for previous observations of anisotropic micro-twinning at GaAs(001) surfaces.

Polarity-Induced Changes in the Nano-Indentation Response of GaAs. E.Le Bourhis, G.Patriarche, L.Largeau, J.P.Rivière: Journal of Materials Research, 2004, 19[1], 131-6