Abstract

InAs quantum dots (QDs) are grown on an In0.53Ga0.47As interlayer and embedded in an InP(100) matrix. They are fabricated via droplet epitaxy (DE) in a metal organic vapor phase epitaxy (MOVPE) reactor. Formation of metallic indium droplets on the In0.53Ga0.47As lattice-matched layer and their crystallization into QDs is demonstrated for the first time in MOVPE. The presence of the In0.53Ga0.47As layer prevents the formation of an unintentional non-stoichiometric 2D layer underneath and around the QDs, via suppression of the As-P exchange. The In0.53Ga0.47As layer affects the surface diffusion leading to a modified droplet crystallization process, where unexpectedly the size of the resulting QDs is found to be inversely proportional to the indium supply. Bright single dot emission is detected via micro-photoluminescence at low temperature, ranging from 1440 to 1600 nm, covering the technologically relevant telecom C-band. Transmission electron microscopy investigations reveal buried quantum dots with truncated pyramid shape without defects or dislocations.

Highlights

  • In the last decade, III–V quantum dots (QDs) fabricated by droplet epitaxy (DE) have attracted great interest due to their suitability for a wide range of applications, ranging from quantum photonics, where they can be employed as efficient quantum emitters of single and entangled photon pairs [1], to photodetectors [2], lasers [3], and solar cells [4]

  • We have investigated the growth of InAs QDs by droplet epitaxy in a metal organic vapor phase epitaxy (MOVPE) environment, for the first time on an In0.53Ga0.47As layer lattice-matched to InP

  • We have shown that the formation of indium droplets appears to be strongly affected by the presence of the interlayer, which modifies the indium surface diffusion

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Summary

Introduction

III–V quantum dots (QDs) fabricated by droplet epitaxy (DE) have attracted great interest due to their suitability for a wide range of applications, ranging from quantum photonics, where they can be employed as efficient quantum emitters of single and entangled photon pairs [1], to photodetectors [2], lasers [3], and solar cells [4]. Very recently DE in combination with droplet etching of InAs/InP QDs emitting at the telecom C-band has been demonstrated [16] and [25], showing an additional and promising approach for nanostructure tuning during MOVPE growth. Such QDs can be employed as fundamental units for the fast-developing quantum information technology, for quantum networks [17,18,19]. Additional promising design strategies include, for instance, embedding InAs QDs in an InGaAs quantum well (QW) This allowed for an efficient post-growth tuning of the QD emission in the telecom O-band via the quantum-confined Stark effect in an entangled light emitting diode (ELED) [17]. This is the first report of the use of this approach with DE by MOVPE

Sample fabrication
Structural and optical investigation via AFM and PL
TEM investigations
Conclusions

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