Quenching of surface-exciton emission from ZnO nanocombs by plasma immersion ion implantation

Abstract

Surface modification of ZnO nanocombs was performed through a Ti plasma immersion ion implantation (PIII) with low bias voltages ranging from 0to5kV to quench surface-originated exciton emission. The ion energy dependent surface modification on ZnO was investigated using transmission electron microscopy and temperature-dependent photoluminescence (PL). The surface exciton (SX) was clearly identified for the as-grown sample at 4.5K, and complete quenching was observed for sample treated with 5kV PIII due to surface state passivation. The SX related surface states were located within 5nm in depth from the surface corresponding to the implantation depth of 5kV PIII. Room-temperature PL enhancement of these surface-modified ZnO nanocombs was observed and discussed. The results show that PIII can become a viable technique for nanostructure surface passivation.