Supersonic molecular beams can provide an alternative method of epitaxy and nucleation at lower temperatures as required for the current drive towards smaller device dimensions. Through seeding techniques, it is possible to increase the translational energy of supersonic molecules from the thermal to the hyperthermal region accompanied by a narrow energy distribution. High translational energy makes it possible for supersonic molecules to directly react with substrate atoms and to migrate on the surface with very high speed. We have demonstrated that small-sized GaAs quantum dots (<5 nm) with extremely high density (>10(12)/cm(2)) are forced on the GaAs(0 0 1) surface by a tri-isobutylgallium (TIBGa) supersonic molecular beam.