Quantum efficiency and oscillator strength of site-controlled InAs quantum dots

We report on time-resolved photoluminescence spectroscopy to determine the oscillator strength (OS) and the quantum efficiency (QE) of site-controlled InAs quantum dots nucleating on patterned nanoholes. These two quantities are determined by measurements on site-controlled quantum dot (SCQD) samples with varying thickness of the capping layer. We determine radiative and nonradiative decay rates, from which we calculate an OS of 10.1±2.6 and an encouragingly high QE of (47±14)% for the SCQDs. The nonideal QE is attributed to nonradiative recombination at the etched nanohole interface.