Tuning of the interdot resonance in stacked InAs quantum dot arrays by an external electric field

Optoelectronic properties of vertically stacked InAs∕GaAs quantum dot (QD) arrays are analyzed. The arrays are grown by molecular beam epitaxy into the intrinsic region of GaAs p-i-n junctions. The structures are extensively characterized by transmission electron microscopy and steady-state and transient photoluminescences. The application of an external bias along growth direction is found to substantially impact the photoluminescence properties. Our results allow for establishing a semiquantitative model for the band structure of biased QD structure, which is used for a consistent interpretation of all data. In particular, we interpret the photoluminescence properties of the structures, which are fully explained by the bias tuning the energetic states of the QDs with respect to each other. Tuning through resonances between the ground states of QDs is found to substantially modify luminescence intensities as well as rise and decay times. This bias sensitivity paves the way for photonic applications of such structures.