Band-Gap Determination of the Native Oxide Capping Quantum Dots by Use of Different Kinds of Conductive AFM Probes: Example of InAs/GaAs Quantum Dots

In most of quantum-dot (QD) systems, the electrical behavior of a single QD is directly linked to the native oxide grown on their surface. Obtaining quantitative electrical measurements requires identifying this oxide well, which is not a trivial task. Due to the use of two conductive atomic force microscopy (C-AFM) probes of different behaviors, C-AFM experiments and local electrical measurements allow one to determine the barrier heights at the interface between InAs QD and the native oxide and then to deduce the oxide band gap. In the case of InAs/GaAs QDs, based on our work and on literature results, it may be assumed that the capping oxide is an InAs oxide enriched in indium.