GaAs/GaP quantum dots: Ensemble of direct and indirect heterostructures with room temperature optical emission

TL;DR

This study investigates GaAs/GaP quantum dots, revealing their optical emission properties and carrier dynamics, with larger dots emitting at room temperature and showing less thermal quenching, highlighting potential optoelectronic applications.

Contribution

It provides detailed analysis of ensemble optical emission and carrier behavior in self-assembled GaAs quantum dots embedded in GaP, emphasizing room temperature luminescence.

Findings

Large quantum dots emit at room temperature.

Emission peaks are at 1.7 and 2.1 eV.

Larger dots show less thermal quenching.

Abstract

We describe the optical emission and the carrier dynamics of an ensemble of self-assembled GaAs quantum dots embedded in GaP(001). The QD formation is driven by the 3.6 % lattice mismatch between GaAs and GaP in Stranski-Krastanow mode after deposition of more than 1.2 monolayers of GaAs. The quantum dots have an areal density between 6 and 7.6x1010 per cm-2 and multimodal size distribution. The luminescence spectra show two peaks in the range of 1.7 and 2.1 eV. The samples with larger quantum dots have red emission and show less thermal quenching compared to the samples with smaller QDs. The large QDs luminescence up to room temperature. We attribute the high energy emission to indirect carrier recombination in the thin quantum wells or small strained quantum dots, whereas the low energy red emission is due to the direct electron-hole recombination in the relaxed quantum dots.