Influence of ZnTe based distributed Bragg reflectors on the yellow range luminescence of self assembled CdTe QDs

TL;DR

This study examines how ZnTe-based distributed Bragg reflectors affect the yellow-range photoluminescence of self-assembled CdTe quantum dots, revealing significant intensity enhancement and effects of growth interruptions on emission line sharpness.

Contribution

It demonstrates the impact of ZnTe-based DBRs on QD luminescence and identifies growth interruptions as a factor influencing emission line broadening.

Findings

Photoluminescence intensity increases by over tenfold with DBRs.

Growth interruptions cause broadening of QD emission lines.

Thicker ZnTe layers help recover sharp emission lines.

Abstract

The influence of a distributed Bragg reflector composed of ZnTe, MgTe, and MgSe superlattices on photoluminescence of self assembled CdTe quantum dots (QD) emitting in the yellow spectral range is investigated. In the case of QDs grown on a distributed Bragg reflector the photoluminescence intensity is enhanced by more than one order of magnitude, whereas the single QD lines are broadened as compared to the case of QDs grown on a ZnTe buffer. Structural and chemical analysis reveal an unintentional formation of a thin ZnSe layer induced by the growth interruption needed for the deposition of the QDs sheet. Sharp emission lines from individual quantum dots are recovered in the case of a thicker ZnTe layer grown prior to the QDs. This indicates that growth interruptions might be responsible for the QD emission line broadening.