Nanostructures grown by MOVPE InAs/InGaAs/Ga(Sb)As quantum dot and GaN/InGaN quantum well structures

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Nanostructures grown by MOVPE InAs/InGaAs/Ga(Sb)As quantum dot and GaN/InGaN quantum well structures

Popis výsledku v původním jazyce

This review talk summarizes some of results achieved during last years of our quantum dot(QD) research. We show that the QD shape (aspect ratio and elongation) significantly influence the QD photoluminescence (PL) spectrum. Magnetophotoluminescence (MPL) cannbe used for determination of the anisotropy of QDs. While the calculated shifts in magnetic field of the energies of higher radiative transitions are found to be sensitive to the lateral elongation, the shift of the lowest transition is determined mainly by the exciton effective mass. This can be used for determining the effective mass and the elongation fairly reliably from the MPL spectra displaying at least two resolved bands. We found the ways to control the QD elongation for vertically correlated InAs/GaAs QDs and consequently the energy difference between PL transitions by adjusting properly the spacer layer thickness. The main goal was to redshift QD PL emission to telecommunication wavelengths of MOVPE prepared InAs/GaAs QDs using InGaAs or GaAsSb strain reducing layer (SRL).The simulation of electron structure in InAs QDs covered by GaAsSb SRL and our experimental results reveal the importance of increasing QD size for obtaining a longer wavelength PL from the type I heterostructure. The type II structure covered by GaAsSb SRL with Sb content near 30 % enabled us to achieve extremely long emission wavelength at 1.8 μm. The high amount of antimony in the SRL causes the preservation of QD size. Increased QD size prolongs the PL wavelength. The type II structures with ground state electrons confined in InAs QDs and ground state holes in GaAsSb SRL have a strong potential in detector and solar cell applicationsnas is demonstrated by photocurrent measurement.

Název v anglickém jazyce

Nanostructures grown by MOVPE InAs/InGaAs/Ga(Sb)As quantum dot and GaN/InGaN quantum well structures

Popis výsledku anglicky

This review talk summarizes some of results achieved during last years of our quantum dot(QD) research. We show that the QD shape (aspect ratio and elongation) significantly influence the QD photoluminescence (PL) spectrum. Magnetophotoluminescence (MPL) cannbe used for determination of the anisotropy of QDs. While the calculated shifts in magnetic field of the energies of higher radiative transitions are found to be sensitive to the lateral elongation, the shift of the lowest transition is determined mainly by the exciton effective mass. This can be used for determining the effective mass and the elongation fairly reliably from the MPL spectra displaying at least two resolved bands. We found the ways to control the QD elongation for vertically correlated InAs/GaAs QDs and consequently the energy difference between PL transitions by adjusting properly the spacer layer thickness. The main goal was to redshift QD PL emission to telecommunication wavelengths of MOVPE prepared InAs/GaAs QDs using InGaAs or GaAsSb strain reducing layer (SRL).The simulation of electron structure in InAs QDs covered by GaAsSb SRL and our experimental results reveal the importance of increasing QD size for obtaining a longer wavelength PL from the type I heterostructure. The type II structure covered by GaAsSb SRL with Sb content near 30 % enabled us to achieve extremely long emission wavelength at 1.8 μm. The high amount of antimony in the SRL causes the preservation of QD size. Increased QD size prolongs the PL wavelength. The type II structures with ground state electrons confined in InAs QDs and ground state holes in GaAsSb SRL have a strong potential in detector and solar cell applicationsnas is demonstrated by photocurrent measurement.

Druh

O - Ostatní výsledky

CEP obor

BM - Fyzika pevných látek a magnetismus

OECD FORD obor

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Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů