Hexagonal core-shell and alloy Au/Ag nanodisks on ZnO nanorods and their optical enhancement effect
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
Nanoscale Research Letters 2014, 9:237 doi:10.1186/1556-276X-9-237Published: 14 May 2014
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.