The influence of cyclic deposition and anneal on growth of isolated and well-dispersed Au nanoisland arrays

Isolated and well-dispersed Au nanoisland arrays were prepared with sputter deposition and post-deposition anneal in a cyclic fashion. Scanning electron microscopy (SEM) characterization and associated image analysis in aspects of nanoisland size, coverage, circularity, and density were performed to investigate the influence of cyclic deposition and anneal (DAA) on the morphology of as-prepared Au nanoisland arrays. This study revealed that, given a fixed amount of Au deposition per cycle, increasing the number of DAA cycles drove Au nanoislands' gradual growth that was interpreted with the increase of their size and coverage and decrease of their density and circularity. In addition, given a fixed amount of total Au deposition, dividing the growth process into more cycles was shown to lower the growth rate of Au nanoislands. Moreover, the as-prepared Au nanoisland arrays were demonstrated to be a viable option as surface-enhanced Raman spectroscopy (SERS) sensing platform whose SERS enhancement was found to be highly dependent upon the size of nanoislands.