AFM images of ringlike structures before and after As exposure of Ga droplets. (a) 600 × 300 nm2 AFM image of the ring structure, formed at a substrate temperature of 500°C, remaining after the Ga droplet was removed by HCl. (b) 3D representation of the ring structure. (c) 600 × 300 nm2 AFM image of the ring structure and nanohole obtained after annealing the Ga droplet under an As flux of 0.70 ML/s for 30 s. (d) 3D image of the same structure where the facets of the highest structure (main sector) surrounding the ring are clearly seen.
Fuster et al. Nanoscale Research Letters 2014 9:309 doi:10.1186/1556-276X-9-309