Impact of He⁺ ion irradiation on CuO nanostructures

Copper (II) oxide (CuO) is a stable, abundant and p-type semiconductor with a narrow bandgap (1.21–1.55 eV). It is a promising material for optoelectronic applications due to its electrochemical, photovoltaic, and catalytic properties. Tailoring its properties through defect engineering—via thermal treatment, doping, and irradiation—has become a key strategy. This study investigates the effects of He⁺ ion irradiation (3.13 × 10¹³ – 3.38 × 10¹⁶ ions/cm²) on nanostructured CuO layers. Scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and positron annihilation spectroscopy were used to correlate morphological, structural, vibrational and defect-related changes. The results reveal an evolution of competing radiation-induced processes: at low doses, irradiation promotes lattice relaxation and defect recombination, while at higher doses it leads to vacancy formation and complex defects, especially in the surface layer.
Overall, these results provide a deeper understanding of defect engineering in nanostructured CuO. Future work will focus on defect engineering through thermal treatments and the development of CuO based heterostructures for applications in sensors and solar cells.