AFM fabrication and characterization of InAs/AlGaSb nanostructures

Abstract

We describe two distinct fabrication processes based on atomic force microscope (AFM) oxidation for nanoscale device fabrication which are particularly useful for GaSb/AlGaSb/InAs heterostructures. One utilizes water immersion which selectively removes the oxidized GaSb region. The other makes use of the enhanced etching rate for oxidized GaSb and AlGaSb layers for a developer solution resulting in the formation of deep grooves down to the InAs channel layer. The latter is used together with a selective InAs etching for the formation of a narrow constricted structure. A 0.3- μm-period corrugation on the GaSb surface is fabricated by the former process in order to make a two-dimensional electron gas (2DEG) with its electron concentration laterally modified. The magnetotransport measurements of the structure show Weiss oscillations corresponding to the corrugation period verifying the successful formation of the laterally modified 2DEG. A single electronic device structure fabricated by the latter shows non-linear I– V characteristic behavior indicating the capability of these AFM oxidation processes for the fabrication of various types of nanostructure devices.