Precise control of configuration, size and density of self-assembled Au nanostructures on 4H-SiC (0001) by systematic variation of deposition amount, annealing temperature and duration

• Published in: CrystEngComm 2016-01, Vol.18 (19), p.3347-3357
• Main Authors: Li, Ming-Yu, Sui, Mao, Pandey, Puran, Zhang, Quan-zhen, Kunwar, Sundar, Salamo, Gregory. J, Lee, Jihoon
• Format: Article
• Language: English
• Subjects: Annealing; Density; Deposition; Droplets; Dwellings; Evolution; Nanoparticles; Nanostructure
• ISSN: 1466-8033; 1466-8033
• DOI: 10.1039/c5ce02439k

Precise control over the configuration, size and density of Au nanoparticles (NPs) has offered an efficient route to enhance and optimize the performance and usability of various NP-based applications. In this study we successfully demonstrate precise control of the configuration, size and density of self-assembled Au nanostructures on 4H-SiC (0001) via systematic variation of the deposition amount, annealing temperature and duration. Depending on the deposition amount at a fixed annealing temperature and duration, the self-assembled Au NPs are successfully fabricated based on the Volmer-Weber growth model, and the NPs nucleate as round dome shapes and evolve into hexagonal nano-crystals with facet formation along with the increased deposition amounts. For the variation of annealing temperature, the Au nanostructures radically develop into two distinct regimes: i.e. irregular Au nano-mounds (regime I) between 400 and 700 °C based on the diffusion limited agglomeration (DLA) model and round dome-shaped droplets (DPs) (regime II) between 750 and 1000 °C. The dwelling time, size and density evolution of the round dome-shaped Au DPs are discussed based on the Ostwald ripening theory. Hexagonal Au nano-crystals, round dome-shaped droplets and irregular nano-mounds were fabricated on GaN (0001) based on the combinational effects of thermal dewetting and surface free energy minimization.