Electrical spin injection into p-doped quantum dots through a tunnel barrier

TL;DR

This paper demonstrates electrical spin injection into p-doped quantum dots via a tunnel barrier, with measurable spin polarization and stability up to 70 K, advancing spintronic device development.

Contribution

It provides experimental evidence of spin-polarized electron injection into quantum dots through a tunnel barrier, with characterization of spin relaxation and polarization stability.

Findings

Electroluminescence circular polarization of 15% at low temperature

Electrical spin injection yield estimated at 35%

Polarization remains stable up to 70 K

Abstract

We have demonstrated by electroluminescence the injection of spin polarized electrons through Co/Al2O3/GaAs tunnel barrier into p-doped InAs/GaAs quantum dots embedded in a PIN GaAs light emitting diode. The spin relaxation processes in the p-doped quantum dots are characterized independently by optical measurements (time and polarization resolved photoluminescence). The measured electroluminescence circular polarization is about 15 % at low temperature in a 2T magnetic field, leading to an estimation of the electrical spin injection yield of 35%. Moreover, this electroluminescence circular polarization is stable up to 70 K.