Gallium-assisted deoxidation of patterned substrates for site-controlled growth of InAs quantum dots

In-situ gallium-assisted deoxidation of ex-situ patterned GaAs (1 0 0) substrates has been investigated, and compared with the more conventionally used hydrogen-assisted deoxidation. A total of 6–8 ML of gallium supplied at a substrate temperature of 420–460 °C has been shown to remove the surface oxide without significantly damaging shallow electron-beam patterned holes. These holes, ∼20 nm deep and ∼100 nm wide, have then been successfully used to control the nucleation site of single InAs quantum dots.