Controlling quantum dot emission by integration of semiconductor nanomembranes onto piezoelectric actuators

Abstract

Abstract This paper reviews the recent advances obtained by integrating semiconductor epitaxial films with embedded self‐assembled quantum dots (QDs) on top of single‐crystal piezoelectric substrates made of lead magnesium niobate–lead titanate (PMN‐PT). This combination allows us to study in detail the effects produced by variable strains (up to about ± 0.2%) on the excitonic emission of single QDs and to add a powerful “tuning knob” to QDs. Biaxial stress can be used to reversibly shift the emission wavelength of QDs in a spectral range wider than 10 meV and to modify the relative binding energies of excitonic species. Anisotropic stress has instead a strong influence on the fine structure splitting of neutral excitons. Finally, we present experimental results on the effect of biaxial strain on the optical modes of microring optical resonators and show a simple approach enabling the compensation of piezo‐creep via a closed‐loop system. magnified image Schematic illustration of a QD membrane integrated on top of a PMN‐PT substrate. Stress provided by the piezoelectric substrate allows broad range tuning of the emission properties of the overlying dots.