Formation of antireflection Zn/ZnO core–shell nano-pyramidal arrays by O2 + ion bombardment of Zn surfaces

ZnO is probably one of the most studied oxides since ZnO nanostructures are a very rich family of nanomaterials with a broad variety of technological applications. Although several chemical techniques offer the possibility to obtain such ZnO nanostructures, here we show that the controlled modification of the zinc surface by low-energy O2 + bombardment leads to the formation of core–shell Zn/ZnO nanopyramidal arrays that suppress the reflection of light decreasing the reflectivity below 6% in the wavelength range of 300–900 nm. This controlled and scalable protocol opens the door to a broad range of possibilities for the use of ion bombardment to produce surface modifications for technological applications in the field of photoelectric devices and solar cells.