Efficient electron spin detection with positively charged quantum dots

TL;DR

This paper demonstrates that positively charged InAs quantum dots exhibit fast carrier capture, long spin lifetime, and high radiative efficiency, making them promising for spintronics and spin detection applications.

Contribution

It introduces a novel application of time- and polarization-resolved photoluminescence up-conversion spectroscopy to study spin dynamics in charged quantum dots, highlighting their advantages over other structures.

Findings

Carrier capture is faster in highly charged dots.

Positively charged dots have long spin lifetimes.

These dots show high radiative efficiency.

Abstract

We report the application of time- and polarization-resolved photoluminescence up-conversion spectroscopy to the study of spin capture and energy relaxation in positively and negatively charged, as well as neutral, InAs self-assembled quantum dots. When compared to the neutral dots, we find that carrier capture and relaxation to the ground state is much faster in the highly charged dots, suggesting that electron-hole scattering dominates this process. The long spin lifetime, short capture time, and high radiative efficiency of the positively charged dots, indicates that these structures are superior to both quantum well and neutral quantum dot light-emitting diode (LED) spin detectors for spintronics applications.