Craters, bumps and onion structures in MoS2 irradiated with MeV C-60 ions

In the scope of a general study of damage creation under high energy deposi tion by electronic excitation in various types of materials, we present her e results relative to irradiations of a lamellar compound with energetic cl uster ions. The projectiles are 20-40 MeV C-60 ions delivered by the tandem accelerator located in Orsay (France). Thin samples suitable for Transmiss ion Electron Microscopy (TEM) are irradiated at 300 K. The damage is charac terised by various TEM techniques, in particular Topographical Contrast Ima ging. We study the influence of the angle of incidence of the projectiles ( varied from normal to grazing incidence) on the morphology of the surface f eatures (craters and bumps). We also characterise the structural modificati ons occurring in the vicinity of the projectile path. We observe in particu lar the formation of "onion like structures" either inside the latent track s or deposited on the surface of the specimens. (C) 1998 Elsevier Science B .V. All rights reserved.