Direct measurement of heavy-hole exciton transport in type-II GaAs/AlAs superlattices

Gilliland, G. D.; Antonelli, Alex; Wolford, D. J.; Bajaj, K. K.; Klem, John F.; Bradley, J. A.

doi:10.1103/physrevlett.71.3717

Cited by 34 publications

(20 citation statements)

References 18 publications

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“…19͑b͔͒ starts to decrease at even higher excitation intensities of about 100 W/cm 2 , indicating that the mobility is high enough to reach the sparsely distributed nonradiative recombination sites. 65 This implies that the QB PL is saturated, in agreement with the experimental data ͓dots in Fig. 19b͔.…”

Section: Samples With Strong Type-ii Charactersupporting

confidence: 80%

“…Thus the decay of the QB PL is mainly controlled by the decay of the (X z 1-hh1͒ exciton density via the QB's and nonradiative traps. 65 A similar case evolves at higher excitation densities ͓Figs. 18͑e͒ and ͑f͔͒ of about 1ϫ10 12 /cm 2 .…”

Section: Samples With Strong Type-ii Charactermentioning

confidence: 88%

“…This attribution is confirmed by the vanishing intensity of the phonon replicas. The simultaneous reduction of the total PL intensity indicates the enhanced trapping of excitons also by nonradiative defects 65 . The PL of the QB's is redshifted in comparison to the (X z 1-hh1͒ zero-phonon transition, and shows an exponential low energy tail with an slope comparable to the tail in the PLE ͑compare Fig.…”

Section: Samples With Strong Type-ii Charactermentioning

confidence: 99%

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Influence of the interface corrugation on the subband dispersions and the optical properties of (113)-oriented GaAs/AlAs superlattices

et al. 1996

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We report on the influence of the interface corrugation in ͑113͒-grown GaAs/AlAs superlattices on their band-edge optical properties both in theory and experiment. We calculate the subband dispersions and the optical anisotropies in a multiband k•p formalism. The dominating contribution to the optical anisotropies is found to be due to the intrinsic properties of the valence-band structure. The corrugation modifies the density of states only slightly, giving no evidence of a quantum-wire behavior. By comparing the calculation with the experimental optical anisotropy, we can estimate the corrugation height to be at most 2 monolayers. The experiments show that deviations from the regular corrugation lead to an anisotropic interface disorder. This gives rise to an enhanced anisotropy of the band-edge states, which was so far attributed to the corrugation itself. The luminescence of the localized type-I states at the band-edge show an enhanced optical anisotropy in comparison to the luminescence of the extended states, revealing the anisotropic nature of their localization sites. In type-II samples, deeply localized, isolated type-I states (⌫ quantum boxes͒ dominate the luminescence at short delays after pulsed excitation and at higher lattice temperatures or excitation densities, due to their strong radiative decay compared to the type-II states. These quantum boxes are observed individually by high spatial and spectral resolution. ͓S0163-1829͑96͒06039-0͔

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Section: Samples With Strong Type-ii Charactersupporting

confidence: 80%

Section: Samples With Strong Type-ii Charactermentioning

confidence: 88%

Section: Samples With Strong Type-ii Charactermentioning

confidence: 99%

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Influence of the interface corrugation on the subband dispersions and the optical properties of (113)-oriented GaAs/AlAs superlattices

et al. 1996

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“…These decay characteristics are explained by our recently proposed defect-trapping model. 10,14 At low temperatures, the excitons are in localized states and decay radiatively. At higher temperatures, the excitons begin to populate mobile states, and they may diffuse along the interface until they interact with defects which cause them to decay nonradiatively.…”

Section: Resultsmentioning

confidence: 99%

Optical studies of heterointerfacial growth interrupts in type-II GaAs/AlAs superlattices by time resolved photoluminescence imaging

Chang¹

1995

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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We have quantitatively characterized the heterointerfaces in type-II GaAs/AlAs short-period structures with various types of growth interrupts. The quality of the heterointerfaces is governed by two factors: the magnitude of the potential fluctuations or interface roughness and the density of nonradiative defect centers incorporated at the heterointerfaces during growth. We have quantified these aspects of the heterointerfaces through photoluminescence ͑PL͒, PL time-decay, and time-resolved PL-imaging measurements. We find that growth interrupts at the normal heterointerfaces significantly improves the quality of the interfaces over growth with no interrupts in regard to the interface roughness. Further, the transport of the excitons along the heterointerfaces may be explained by interface roughness induced scattering. We also find that growth interrupts at only the normal interfaces substantially reduces the nonradiative trap densities at the heterointerfaces.

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“…The mixing of the X z and ⌫ subbands due to the superlattice structure in the ͓001͔ growth direction was investigated both experimentally [5][6][7] and theoretically. 8,9 The interface roughness of the structures plays an important role for the indirect exciton mobility [10][11][12][13][14] and for the mixing of the X x,y subbands with the ⌫ subband in the ͓001͔ growth direction 12 and all X subbands for growth directions other than ͗100͘.…”

Section: Introductionmentioning

confidence: 99%

Luminescence dynamics in type-II GaAs/AlAs superlattices near the type-I to type-II crossover

1996

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We report on a study of the time-resolved luminescence of type-II GaAs/AlAs superlattices near the type-I to type-II crossover. In spite of the slight type-II band alignment, the luminescence is dominated by the type-I transition. This is due to the inhomogeneous broadening of the type-I transition and the weak type-II oscillator strength, leading to a dominant luminescence of deeply localized type-I states. The relaxation within these localized states is found to be in agreement with a hopping model. At higher temperatures and excitation densities, the AlAs X minima act as an electron reservoir, leading to a strong increase of the luminescence decay time.

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Direct measurement of heavy-hole exciton transport in type-II GaAs/AlAs superlattices

Cited by 34 publications

References 18 publications

Influence of the interface corrugation on the subband dispersions and the optical properties of (113)-oriented GaAs/AlAs superlattices

Influence of the interface corrugation on the subband dispersions and the optical properties of (113)-oriented GaAs/AlAs superlattices

Optical studies of heterointerfacial growth interrupts in type-II GaAs/AlAs superlattices by time resolved photoluminescence imaging

Luminescence dynamics in type-II GaAs/AlAs superlattices near the type-I to type-II crossover

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