Indium antimonide (InSb) and gallium antimonide (GaSb) are narrow-bandgap III–V semiconductors whose structures can be strongly modified by energetic heavy ions. As an ion passes through a material, it deposits energy along a narrow path, creating local damage known as an ion track. At a threshold fluence, where overlapping tracks provide near-complete coverage of the irradiated region, the accumulated damage reorganizes into a porous structure.

This seminar examines how ion irradiation induces porosity in bulk and thin-film InSb and GaSb. The irradiations use ion energies ranging from 125 to 185 MeV. At these energies, nuclear collisions are unlikely; instead, energy is transferred predominantly through electronic excitations, enabling investigation of the effects of different energy-deposition profiles. Ion energy influences both the amount of energy deposited and the depth at which it is deposited, thereby affecting defect production, defect accumulation, and pore formation. In bulk InSb, porosity develops beneath the surface, where the local energy deposition and defect concentration are favourable for pore growth.

The thin films have thicknesses much smaller than the projected range of the incident ions at the selected irradiation energies. The ions therefore traverse the entire film before reaching the end of-range region, where nuclear stopping becomes significant. This geometry isolates the structural effects of electronic stopping, allowing it role in porosity formation to be examined independently. At the same time, the limited thickness and proximity of free surfaces modify defect migration and pore evolution, leading to swelling, restructuring, and the formation of single or multiple crumpled sheets. Understanding these differences is important for controlling irradiation-induced porosity and tailoring semiconductor nanostructures. Overall, this work shows how energetic ions can be used to transform dense semiconductor materials into porous nanostructures, while highlighting the importance of the material type and geometry in controlling that transformation.