Scale bar = 20 nm. EDS mapping for (b) Au and (c) Ag elements. It is also known that with sufficient thermal energy, Au and Ag can easily intermix due to similar lattice structure and high inter-diffusion rate. In solution-synthesized AZ 628 price nanoparticles, generally under relatively low annealing temperature (<200°C), Au/Ag core-shell nanoparticles start to convert to alloy nanoparticles [26]. In the solution process, annealing always needs hours to complete.

As a contrary, the rapid annealing here only takes tens of seconds; thus, the status of Ag atoms will be dynamically determined by the thermal energy. In this case, relatively low temperature may not provide enough thermal energy for intermixing. As a result, with 500°C rapid annealing, sample A still displays a quasi ‘core-shell’ morphology. With longer duration of annealing or higher annealing temperatures, the mixing of Au and Ag will become much more obvious. Figure 5a,b,c,d shows the STEM images and EDS mapping of Au, Ag, and Zn for composite nanodisk sample C. In contrary to sample A, the EDS mapping signal results indicate that the Au and Ag signals SBI-0206965 cell line are almost totally intermixed.

The ratio of the AuM and AgL intensity is approximately 1.2:1. Considering that the Cliff-Lorimer factor (K AB for Au and Ag) of this EDS system is 1.52, this suggests that this alloy nanodisk is Au0.51Ag0.49. Sample B is an intermediate sample, and the STEM characterization yields an elemental distribution in between A and C (not shown here). Figure 5 TEM image of sample C and EDS mapping for Au, Ag, and Zn elements. (a) TEM image of one nanodisk in sample C (high temperature annealing). Scale bar = 5 nm. EDS mapping for (b) Au, (c) Ag, Calpain and (d) Zn elements. Besides, the material characteristics and the optical properties of metal/semiconductors are

also with profound interest. Previous studies suggest that the ability to tune ZnO’s PL recombination by Au and Ag nanoparticles depends on the efficiency of carrier and plasmon coupling as well as carrier transfer between metal and ZnO [27–31]. Particularly, the authors in [31] shows that the alignment of metal energy bands with ZnO also plays an important role. Here, samples with different annealing conditions were employed to test the optical properties. The samples used in the optical characterization are aligned nanorods with relative short length to highlight metal/ZnO interface effect (approximately 1 μm), as shown in Figure 6a. In order to exclude the formation of metal nanoparticles on the side walls of ZnO nanorods, poly (methyl methacrylate) (PMMA) was spun on the sample to fill the inter-nanorod space (Figure 6a). The top surface was then rapidly cleaned by acetone and deposited with metal nanodisks. The PMMA was subsequently removed by hot acetone for the annealing process. The TEM image in Figure 6b suggests that the metal nanodots are greatly suppressed on the side walls of ZnO nanorods.