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

Abstract

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.