Electronic structure of nanometer-scale quantum dots created by a conductive atomic force microscope tip in resonant tunneling structures

Abstract

We report on a self-consistent electronic structure calculation for an AlAs/InGaAs/AlAs near-surface quantum well with a conductive atomic force microscope tip placed immediately above and biased at a positive voltage. The result indicates that the application of a modest voltage (∼V) to the tip creates zero-dimensional electron states (quantum dot) in the well with lateral confinement size <10 nm. These discrete states can be directly probed by resonant tunneling using the tip as an electrode. We also propose that p doping in the cap layer is very useful for the achievement of tighter lateral confinement.