AFM Lithography of Antidot Arrays on GaSb

摘要

We have performed local anodic oxidation (LAO) on the free GaSb surface of a GaSb–InAs–GsSb double heterostructure (DHET) with the help of an atomic force microscope(AFM). Patterns are created by applying a voltage in the range 10–20V to a conducting tip.We have succeeded in drawing both rectangular and hexagonal arrays of oxide dots withdiameters of as little as 30nm and heights of 4–6nm, while deoxidation suggests an oxidationdepth of approximately twice this height. This has allowed lattice periods of 75nm whilemaintaining a high uniformity.The use of gold coated probes has enabled us to reduce the required time per dot to 100–250ms, facilitating the creation of larger arrays within the constraints imposed by instrumentdrift.The minimum feature size available with this method is of the same order of magnitudeas the estimated Fermi wavelength of the electron gas in the InAs layer of the DHET.The effective potential modulation imposed by the dots therefore promises to lead to theobservation of novel quantum effects in the magnetoresistance of the devices.