Fabrication and Comparison of Self-Organized Ag and Au Nanodots on Ti/MgO(001) Substrates

• Published in: Journal of nanoscience and nanotechnology Vol. 20; no. 5; p. 3231
• Main Authors: Kim, Woo-Seong, Oh, Kwang-Hun, Kim, Tae-Hwan, Shin, Seung-Hyun, Um, Tae-Woong, Koh, Jung-Hyuk, Kamiko, Masao, Ha, Jae-Geun
• Format: Journal Article
• Language: English
• Published: United States 01.05.2020
• ISSN: 1533-4899
• DOI: 10.1166/jnn.2020.17385

We analyze and compare the differences in the dewetting phenomena and crystal structure between Ag(5.0 nm) and Au(5.0 nm) layers deposited on a Ti(1.0 nm) seed layer coated onto a MgO(001) substrate. The samples are deposited at room temperature and annealed at 350-450 °C for 5 h. The surfaces of both Ag/Ti and Au/Ti films exhibit a completely separated island structure, subsequently leading to the formation of a nanodot array after annealing. Based on atomic force microscopy (AFM) analysis, we conclude that the dewetting progression speed of Ag/Ti films is higher than that of Au/Ti films. Based on X-ray diffraction (XRD) results, the Ti thin film acts as a seed layer, assisting the epitaxial growth of fcc-Ag(001) nanodots on the MgO(001) substrate, whereas in the case of Au/Ti, the Au layer grows non-epitaxially on the MgO(001) substrate, which is related to the difference in the surface energies of Ag and Au. Furthermore, the optical absorbance spectra of the self-organized Ag and Au nanodots with the Ti seed layer are obtained in the visible light range and the optical properties of Ag and Au nanodots are compared.