Formation of nanostructures in a heterojunction with a deeply located 2D electron gas via the method of high-voltage anodic-oxidation lithography using an atomic-force microscope

Abstract

A technique of high-voltage local anodic oxidation of the surfaces of Ga[Al]As-based heterostructures with the use of an atomic-force microscope is described. The application of a pulsed voltage and use of semicontact operating regime of the atomic-force microscope allowed obtainment of a locally depleted 2D electron gas (2DEG) at an unusually large depth of 80 nm from the surface. This circumstance makes it possible to create 2DEG-based ballistic nanostructures characterized by a high mobility of carriers. The technique of preparing an open quantum dot in the 2DEG with a mobility of μ ≈ 3 × 106 cm2/(V s) at 4.2 K is described and the results of low-temperature test measurements of its conductivity are presented.