Erasable electrostatic lithography for quantum components

Abstract

Erasable electrostatic lithography (EEL) is a new lithographic technique where patterns of charge are drawn on a GaAs surface with a low-temperature scanning probe. The surface charge locally depletes electrons from a subsurface 2D electron system to define a quantum component ready for measurement in the same low-temperature high-vacuum environment, enabling short lithography to measurement cycles and high productivity. Charge patterns are erased locally with the scanning probe or globally by illuminating the sample with red light. This paper provides background and characterization for the EEL technique, then describes the construction and measurement of a quantum billiard. A quantum billiard is a large open quantum dot which exhibits both chaotic behaviour and classical orbits. Scanning probe images, made with the same apparatus in the same environment, reveal features associated with the classical closed-loop electron trajectories inside the quantum billiard.