Electron and hole tunneling in a moderate density quantum dot ensemble with shallow confinement potentials

Abstract

Data are presented on InAlGaAs quantum dot ensembles that possess different degrees of lateral tunnel coupling for electrons and holes. Atomic force microscope images show that even for moderate densities (∼4.8×1010 cm−2), but with shallow potentials, many dots of an ensemble can be in such close proximity that tunneling is expected for both electrons and holes. On average, however, holes remain confined while electrons freely tunnel. Even with electron tunneling, single dot emission is observed for small area light emitting diodes.