Nano-oxidation of semiconductor heterostructures with atomic force microscopes:: technology and applications

Tunable nanostructures can be patterned in Ga[A1]As heterostructures with an atomic force microscope (AFM). Oxidizing the GaAs cap layer locally by applying a voltage to the AFM tip leads to depletion of the electron gas underneath the oxide. Here, we describe this type of AFM lithography as a tool to fabricate tunable nanostructures. Novel technological options are discussed, and the electronic properties of the resulting confinement is characterized. As an example for the versatility of this technique, we present electronic transport measurements on quantum wires.