Epitaxial growth and Photoluminescence Excitation spectroscopy of CdSe Quantum Dots in (Zn,Cd)Se barrier

TL;DR

This paper reports on the epitaxial growth and optical characterization of CdSe quantum dots embedded in a novel (Zn,Cd)Se barrier, demonstrating tunable emission, polarization transfer, and Mn ion doping for potential magnetooptical applications.

Contribution

It introduces a new epitaxial structure enabling emission tuning below Mn$^{2+}$ transition energy and demonstrates doping with single Mn ions in CdSe quantum dots.

Findings

Emission shifted down to 1.87 eV below Mn$^{2+}$ transition energy

Achieved polarization transfer efficiency of 26%

Successfully doped quantum dots with single Mn$^{2+}$ ions

Abstract

Design, epitaxial growth, and resonant spectroscopy of CdSe Quantum Dots (QDs) embedded in an innovative (Zn,Cd)Se barrier are presented. The (Zn,Cd)Se barrier enables shifting of QDs energy emission down to 1.87 eV, that is below the energy of Mn$^{2+}$ ions internal transition (2.1 eV). This opens a perspective for implementation of epitaxial CdSe QDs doped with several Mn ions as, e. g., the light sources in high quantum yield magnetooptical devices. Polarization resolved Photoluminescence Excitation measurements of individual QDs reveal sharp ($\Gamma <$ 150 $\mu$eV) maxima and transfer of optical polarization to QD confining charged exciton state with efficiency attaining 26 %. The QD doping with single Mn$^{2+}$ ions is achieved.