Creating surface nanostructures in GaAs by MeV Au2+ ions

GaAs(100) samples were exposed to 1.5 MeV Au2+ ions at room temperature. Changes in the surface morphology and the structural properties of ion irradiated GaAs samples were studied as a function of ion fluence in the range of 1 × 1014–1 × 1015 ions cm− 2 at an incident angle of 75°. The samples were investigated by atomic force microscopy and micro-Raman spectroscopy. We observe the formation of nanodots on the irradiated surfaces. The room-temperature micro-Raman investigation of these nanostructures reveals optical phonon softening due to phonon confinement in the surface nanostructures. The observed features are discussed in the framework of ion-matter interaction in the MeV regime.