Ion–solid interactions at the extremes of electronic energy loss: Examples for amorphous semiconductors and embedded nanostructures

•Identification and characterisation of ion tracks in amorphous Si and Ge.•Mechanistic understanding of porous layer formation in amorphous Ge.•Insight into the shape transformation in semiconductor and metal nanoparticles.•Demonstration of the synergies between experiment, modelling and simulation. A selection of ion–solid interactions in the swift heavy-ion irradiation regime is reviewed. We consider the effects of electronic energy loss at tens of keV/nm on both bulk material and nanostructures embedded in a matrix. Specific examples include ion track formation at low ion fluences in bulk Si and Ge and porous layer formation at high ion fluences in bulk Ge. In addition, the intriguing shape and phase transformations observable at high ion fluences in Ge and metallic nanoparticles embedded in bulk SiO2 are examined and compared. Experiment, modelling and simulation are combined synergistically as we seek fundamental atomistic insight into these unique yet poorly understood processes operative only at the extremes of electronic energy loss.