Lithography

Quantum wells are covered with a polymer mask and exposed to an electron or ion beam. The surface is covered with a thin layer of metal, then cleaned and only the exposed areas keep the metal layer. Pillars are etched into the entire surface. Multiple layers are applied this way to build up the properties and size wanted. Disadvantages: slow, contamination, low density, defect formation.

Resulting quantum dot etched in GaAs/AlGaAs superlattice.
L. Jacak, P. Hawrylak, A. Wojs. Quantum dots fig. 2.2