Desorption dynamics of oxide nanostructures fabricated by local anodic oxidation nanolithography

We studied the properties of GaAs oxides which were grown by local anodic oxidation (LAO) nanolithography using an atomic force microscope. We find that the LAO structures desorb under irradiation with soft x-rays (130 eV). We analyzed the desorption process in detail by time-resolved photoelectron spectroscopy. We observe that even in the first stages of light exposure the LAO oxide is mainly composed of Ga2O, with a small fraction of Ga2O3 and As oxides. The As oxides are located only in the surface layers of the LAO oxide where they account for 10% of the oxide. Within 160 minutes of exposure they completely desorb. Moreover, we find evidence for the presence of unoxidized GaAs embedded in the LAO oxide