Effective photoluminescence modification of ZnO nanocombs by plasma immersion ion implantation

Surface defects passivation of ZnO nanocombs was performed through a Ti plasma immersion ion implantation (PIII) with low bias voltages ranging from 0-10 kV. The room temperature near-band-edge emission was enhanced for modified ZnO nanostructures while the defect-related green band was completely quenched. Detailed temperature dependence PL revealed that the deep-level emissions were surface related and it was the most affected recombination processes by PHI, whereas the surface exciton related emission was slowly quenched as the ion energy increased. Time-resolved PL shows that the lifetime of the UV emission has been enhanced whereas the long lifetime of visible emission of the untreated ZnO nanocombs has been largely shortened. Our work demonstrates that metal ion PIII can be an effective way for surface modification/passivation of ZnO nanostructures to improve the optical properties.