Figure 2
From: Dynamics of mass transport during nanohole drilling by local droplet etching
Schematic representation of the different steps of a Ga on AlGaAs droplet etching process. (a) Planar deposition of Ga with flux F Ga yielding an increase of the Ga adatom density n 1. Ga droplets are nucleated by collisions between diffusing Ga adatoms. (b) Droplet shape establishment with increasing coverage and increase of the droplet volume by adatom attachment with rate R A . (c) Etching and removal of substrate material by As diffusion with rate R E and droplet material detachment with rate R D during post-growth annealing. The detached Ga atoms crystallize a thin GaAs layer with background As of flux F As. (d) Final hole with depth d and side-facet angle α surrounded by a GaAs wall.