ABSTRACT
Abstract. Compound semiconductors, such as GaAs, have a similar hardness to Si, even though their flow stresses (as a proportion of their shear modulus) are lower. Previous observations under nanoindents in Si have shown that deformation occurs by a phase transformation while deformation in GaAs is dominated by twinning [1]. In this paper we have studied the influence of temperature on the deformation of GaAs under a Berkovich indenter, using an atomic force microscope and a transmission electron microscope to characterise the deformation behaviour. Electron transparent cross-sections through the deformed region were prepared using a focused ion beam. It is shown that at low temperatures, the hardness impression is accommodated within the material, deformation occurring predominantly by twinning. At higher temperatures (300 °C) pile up around the indent is observed with deformation occurring predominantly by dislocation motion.
