AFM images of different stages of the nanodrilling process and profiles along thedirection. (a-e) 500 × 500 nm2 AFM images of different stages of the nanodrilling process during the Ga droplet consumption. (f) Profiles along the direction [dashed line marked in (e)], normalized to the smallest ring diameter, showing the progressive droplet reduction, the local etching of the GaAs substrate, and the progressive filling of the part of the hole free of Ga droplet.
Fuster et al. Nanoscale Research Letters 2014 9:309 doi:10.1186/1556-276X-9-309