Band structure engineering in strain-free GaAs mesoscopic systems

Nanotechnology
Vanessa Orsi GordoChristoph Deneke

Abstract

We investigate the optical properties of strain-free mesoscopic GaAs/Al x Ga1 - x As structures (MGS) coupled to thin GaAs/Al x Ga1 - x As quantum wells (QWs) with varying Al content (x). We demonstrate that quenching the QW emission by controlling the band crossover between AlGaAs (X-point) and GaAs (Γ-point) gives rise to long carrier lifetimes and enhanced optical emission from the MGS. For x = 0.33, QW and MGS show typical type-I band alignment with strong QW photoluminescence emission and much weaker sharp recombination lines from the MGS localized exciton states. For x ≥ 0.50, the QW emission is considerably quenched due to the change from type-I to type-II structure while the MGS emission is enhanced due to carrier injection from the QW. For x ≥ 0.70, we observe PL quenching from the MGS higher energy states also due to the crossover of X and Γ bands, demonstrating spectral filtering of the MGS emission. Time-resolved measurements reveal two recombination processes in the MGS emission dynamics. The fast component depends mainly on the X - Γ mixing of the MGS states and can be increased from 0.3 to 2.5 ns by changing the Al content. The slower component, however, depends on the X - Γ mixing of the QW states and is associa...Continue Reading

References

Nov 15, 1995·Physical Review. B, Condensed Matter·A Franceschetti, A Zunger
Jan 22, 2014·Nanoscale·Xinlei LiGregory J Salamo
Jun 13, 2014·Optics Express·Sabina HatchHuiyun Liu
Jan 23, 2017·Nanoscale Research Letters·Saimon Filipe Covre da SilvaChristoph Deneke
May 27, 2017·Nature Communications·Robert KeilOliver G Schmidt
Jun 19, 2018·Nanotechnology·Sergio BiettiStefano Sanguinetti
Dec 18, 2018·Science Advances·Marcus ReindlRinaldo Trotta

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