We give an overview on the fabrication and applications of deep nanoholes in semiconductor surfaces generated by self-assembled drilling with liquid metal droplets as etchant. The method is fully compatible with conventional molecular beam epitaxy equipment. We discuss the mechanism of nanohole formation and two applications: the creation of GaAs quantum rings and of GaAs quantum dots by nanohole filling. (C) 2010 Elsevier B.V. All rights reserved.