Atomic force microscope nanofabrication of InAs/AlGaSb heterostructures

We employ an atomic force microscope (AFM) for the fabrication of InAs/Al(Ga)Sb nanostructures. In order to make nanoscale modifications in the two-dimensional electron gas (2DEG) system, we apply an AFM oxidation process for GaSb, for the first time. We found that the oxidation of GaSb occurs for tip voltages over 7-8 V and that the oxidized GaSb region can be selectively removed by immersion in water for 10 min. We successfully fabricate a lateral periodic structure on the GaSb cap layer using AFM oxidation with a 0.3 mu m spacing. The induced increase in the 2DEG concentration is as high as 80% due to the surface modification. The magnetotransport measurement also implies structural modification of the 2DEG system.