Multiple time scale blinking in InAs quantum dot single-photon sources

We use photon correlation measurements to study blinking in single, epitaxially grown self-assembled InAs quantum dots situated in circular Bragg grating and microdisk cavities. The normalized second-order correlation function g⁽²⁾(τ) is studied across 11 orders of magnitude in time, and shows signatures of blinking over time scales ranging from tens of nanoseconds to tens of milliseconds. The g⁽²⁾(τ) data is fit to a multilevel system rate equation model that includes multiple nonradiating (dark) states, from which radiative quantum yields significantly less than 1 are obtained. This behavior is observed even in situations for which a direct histogramming analysis of the emission time-trace data produces inconclusive results.