Influences of Si sheet doping densities on the morphological, conductive and optical characteristics of InAs/GaAs quantum dots

TL;DR

This study examines how different Si sheet doping densities affect the morphology, conductivity, and optical properties of InAs/GaAs quantum dots, revealing significant enhancements in photoluminescence without morphological changes.

Contribution

It demonstrates that Si doping enhances PL intensity in InAs QDs and clarifies the doping level's impact on electrical and optical properties, with detailed analysis of morphology and conductivity.

Findings

Si doping does not alter QD morphology.

PL intensity increases up to 35 times at optimal doping.

Conductivity decreases sharply at high doping levels.

Abstract

The influences of Si sheet doping levels on the properties of InAs/GaAs quantum dots (QDs) are investigated by atomic force microscopy (AFM) and photoluminescence (PL). AFM measurements reveal that Si sheet doping doesn't change the morphology of InAs QDs. Conductive AFM exhibits a quick current decrease when the Si doping density reaches 5\times1011cm-2. PL measurements show that the Si doping can significantly enhance the PL intensity. The PL peak intensity of InAs QDs doped to 5\times1011cm-2 is increased about thirty-five times from that of the undoped ones at 300K. The results observed here can be explained by a supposed positive-charged, strain-relaxed Si-doped thin InAs layer inside the InAs QDs.