Effects of Pt capping and annealing on the photoluminescence properties of ZnO nanorods

摘要

Pt-capped ZnO nanorods were synthesized by the thermal evaporation of a mixture of ZnO and graphite powder at 900℃ followed by Pt sputter-deposition and thermal annealing. Photoluminescence (PL) showed that the intensity of near-band edge (NBE) emission of ZnO nanorods was enhanced significantly by Pt-capping and annealing in a H_2 atmosphere. The intensity ratio of NBE emission to the deep level emission, I_(nbe)/1_(dl) of the Pt-capped ZnO nanorods after annealing in a H_2 atmosphere was -11 times higher than that of the unannealed, uncapped ZnO nanorods. The increase of the I_(nbe)/I_(dl) might be due to a combination of carrier transfer from the defect level to the Fermi level of Pt nanopartides, surface plasmon resonance in Pt nanopartides and hydrogen passivating deep level defects.