Real-time detection of every Auger recombination in a self-assembled quantum dot

TL;DR

This paper demonstrates real-time detection of Auger recombination events in a self-assembled quantum dot using two-color laser excitation, revealing tunable charge control and statistical properties of the process.

Contribution

It introduces a method for real-time monitoring of Auger recombination in self-assembled quantum dots and explores its potential for optical charge control.

Findings

Real-time detection of Auger events achieved.

Fano factor tunability from Poissonian to sub-Poissonian.

Auger process enables optical control of charge state.

Abstract

Auger recombination is a non-radiative process, where the recombination energy of an electron-hole pair is transferred to a third charge carrier. It is a common effect in colloidal quantum dots that quenches the radiative emission with an Auger recombination time below nanoseconds. In self-assembled QDs, the Auger recombination has been observed with a much longer recombination time in the order of microseconds. Here, we use two-color laser excitation on the exciton and trion transition in resonance fluorescence on a single self-assembled quantum dot to monitor in real-time every quantum event of the Auger process. Full counting statistics on the random telegraph signal give access to the cumulants and demonstrate the tunability of the Fano factor from a Poissonian to a sub-Poissonian distribution by Auger-mediated electron emission from the dot. Therefore, the Auger process can be used to tune optically the charge carrier occupation of the dot by the incident laser intensity; independently from the electron tunneling from the reservoir by the gate voltage. Our findings are not only highly relevant for the understanding of the Auger process, it also demonstrates the perspective of the Auger effect for controlling precisely the charge state in a quantum system by optical means.