| Summary: | 碩士 === 國立臺灣大學 === 光電工程學研究所 === 106 === The behaviors of Ag nanoparticle (NP) reorganization on various templates are demonstrated. The reorganization of Ag NPs may lead to the clustering of Ag NPs to form larger particles or the formation of a networked snowflake-like Ag pattern. Such a phenomenon is caused by the generation of hot electrons in Ag NPs and their migration into the template such that Ag+ ions are formed and dissolved in the adsorbed water for diffusing around. When the Ag+ ions combine with the electrons in the template, it can settle for forming a new Ag NP or connecting neighboring Ag NPs. Therefore, this reorganization process requires the critical factors of (1) the illumination of photons with energy higher than the interband or intraband transition energy of Ag for generating hot electrons in an Ag NP; (2) low enough potential barrier between an Ag NP and the substrate for hot electrons to overcome; (3) conductive substrate for lateral electron transport; and (4) available water vapor around the Ag NP for being adsorbed onto the Ag NP and the template surface. For testing these required factors, we use Ga- and N-face GaN, Si- and C-face SiC templates for observing different Ag NP reorganization behaviors. Two emission wavelengths are used for understanding the effects of electron excitations in Ag NP and template.
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