Observation of increased photoluminescence decay time in strain-induced quantum-well dots

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Abstract
We report on the observation of increased photoluminescence (PL) decay time in strain‐induced quantum‐well dots (SIQWDs), 120 nm in diameter. Lateral confinement was generated in a GaAs quantum well (QW) by etching a doubly exposed grating pattern into a pseudomorphic, strained layer of In0.35Ga0.65As which overlies the QWs. By spacing three QWs of different widths at varying depths from the In0.35Ga0.65As stressor, lateral strain confinement and vertical strain propagation are directly resolved by the PL spectra. The decay time of the heavy‐hole‐like excitons in the SIQWDs from the uppermost QW is 420 ps at 2 K, which is longer than the 270 ps PL decay time of the heavy‐hole exciton in the reference QW sample.