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Open Access Nano Express

Hexagonal core-shell and alloy Au/Ag nanodisks on ZnO nanorods and their optical enhancement effect

Junming Zhang1, Boya Lai1, Zuxin Chen1, Sheng Chu1*, Guang Chu2 and Rufang Peng3

Author Affiliations

1 State Key Laboratory of Optoelectronic Materials and Technology, Sun Yat-sen University, Guangzhou 510275, China

2 School of Metallurgy Engineering, Central South University, Changsha 41008, China

3 School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang615082, China

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Nanoscale Research Letters 2014, 9:237  doi:10.1186/1556-276X-9-237

Published: 14 May 2014

Abstract

Au and Ag hybrid hexagonal nanodisks were synthesized on ZnO nanorods' (0002) surface via a new two-step deposition-annealing method. The structural, compositional, as well as optical investigations were carried out systematically to find out the nanodisks' formation mechanism and optical enhancement effect. It was shown that the core-shell Au/Ag nanodisk can be formed under rapid annealing temperature of 500°C, while Au/Ag alloy nanodisks are formed if higher temperatures (>550°C) are applied. The optical effect from these nanodisks was studied through photoluminescence and absorption spectroscopy. It was found that the carrier-plasmon coupling together and carrier transfer between metal and ZnO contribute to the emission enhancement. Furthermore, the results suggest that the composition of nanodisk on the vicinity of metal/ZnO interface plays an important role in terms of the enhancement factors.

Keywords:
Metal nanoparticle; Nanodisk; Zinc oxide; Plasmonic