Surface potential effect on excitons in AlGaN/GaN quantum well structures

Pozina, Galia; Hemmingsson, Carl; Amano, Hiroshi; Ḿonemar, B.

doi:10.1063/1.4793568

Cited by 10 publications

(7 citation statements)

References 22 publications

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“…The band profile of the QW structures have been calculated using a self-consistent solution of the Schrödinger and Poisson equations 13 with the same material parameters for AlGaN and GaN as used in Ref. 17 . Calculations were performed for structures having d = 3, 6 and 9 nm for different surface potentials between 0.1 and 0.5 eV.…”

Section: Methodsmentioning

confidence: 99%

Dynamic properties of excitons in ZnO/AlGaN/GaN hybrid nanostructures

Forsberg

Hemmingsson

Amano

et al. 2015

Sci Rep

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Hybrid samples based on ZnO colloidal nanocrystals (NCs) deposited on AlGaN/GaN quantum well (QW) structures with different top barrier thickness d = 3, 6 and 9 nm are studied by time-resolved photoluminescence. Thermal behavior of the QW exciton lifetime in the hybrids and in the bare QW structures has been compared and it has been found that the QW exciton recombination rate increases in the hybrid having d = 3 nm and decreases in the hybrid with d = 6 nm, while no change has been observed for the structure with d = 9 nm. It is suggested that non-radiative resonance energy transfer from the QW excitons to the ZnO NCs and a variation of the surface potential can both influence the QW exciton lifetime in the hybrids.

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Section: Methodsmentioning

confidence: 99%

Dynamic properties of excitons in ZnO/AlGaN/GaN hybrid nanostructures

Forsberg

Hemmingsson

Amano

et al. 2015

Sci Rep

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“…In this case, the overlap between electron and hole wavefunctions is reduced compared to the ground state and, thus, the radiative recombination time becomes longer. Clearly, the effect can be observed at enhanced temperatures only if the contribution of radiative recombination rate exceeds the nonradiative recombination, which requires a high structural quality of heterostructures and have been observed in other high‐quality QW structures . The structural quality was also confirmed by the temperature dependence of spectrally and time‐integrated PL intensity showing only a weak decrease of ∼10% at 100 K compared to low temperatures.…”

Section: Resultsmentioning

confidence: 78%

Nonlinear behavior of the emission in the periodic structure of InAs monolayers embedded in a GaAs matrix

Pozina

Kaliteevski

Nikitina

et al. 2016

Phys. Status Solidi B

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We report time‐resolved photoluminescence (TRPL) measurements performed at different temperatures for the Bragg structure containing 60 InAs monolayer‐based quantum wells (QWs) periodically arranged in a GaAs matrix. TRPL data reveal an appearance of the additional superradiant (SR) mode originated from coherent collective interaction of QWs. The SR mode is not manifested in the case if a small number of QWs is excited, then only an exciton emission related to the InAs QWs dominates the PL spectrum. The SR mode demonstrates a superlinear dependence of the intensity and radiative decay rate on the excitation power and its intensity increases at elevated temperatures compared to the excitonic emission. The photoluminescence delay time is much shorter for the SR mode indicating that the relaxation of hot excitons can occur via stimulated scattering processes. The specific behavior of the SR emission can have a strong potential for different applications such as optical logic devices, superluminescent diodes, optical switches, and low‐threshold lasers. Time‐resolved photoluminescence image at low temperature for the Bragg structure consisting of InAs monolayer‐based quantum wells (inset).

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“…This is a rather reasonable approximation though a small deviation from the law at temperatures QWs near the surface and the effect might be opposite compared to NRET. The influence of the surface potential on luminescence properties in polar III-nitride heterostructures has been considered previously [7,8]. The TRPL measurements have been repeated for the hybrid structures after a period of 1 year to check if the samples fabricated using colloidal NCs are stable.…”

Section: Resultsmentioning

confidence: 99%

Time-resolved photoluminescence properties of hybrids based on inorganic AlGaN/GaN quantum wells and colloidal ZnO nanocrystals

Forsberg

Hemmingsson

Amano

et al. 2015

Superlattices and Microstructures

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Dynamic properties are studied for the AlGaN/GaN quantum well (QW) structures with and without the coating of colloidal ZnO nanocrystals (NCs). The QW exciton recombination rate was reduced in such hybrids compared to the bare QW structure only in the sample with the thinnest cap layer of 3 nm. Assuming that one of the recombination mechanisms in this hybrid is non-radiative resonant energy transfer (NRET) between the QW and the energy acceptor material i.e. ZnO NCs, the maximum pumping efficiency was estimated to be 42% at 60 K. The NRET effect is, however, vanished after several months despite that the hybrid structures are composed of chemically stable components.

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Surface potential effect on excitons in AlGaN/GaN quantum well structures

Cited by 10 publications

References 22 publications

Dynamic properties of excitons in ZnO/AlGaN/GaN hybrid nanostructures

Dynamic properties of excitons in ZnO/AlGaN/GaN hybrid nanostructures

Nonlinear behavior of the emission in the periodic structure of InAs monolayers embedded in a GaAs matrix

Time-resolved photoluminescence properties of hybrids based on inorganic AlGaN/GaN quantum wells and colloidal ZnO nanocrystals

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