Evolution process of cross-hatch patterns and reduction of surface roughness in (InAs)m(GaAs)n strained short-period superlattices and InGaAs alloy layers grown on GaAs

Samonji, Katsuya; Yonezu, Hiroo; Takagi, Yasufumi; Ohshima, Naoki

doi:10.1063/1.370891

Cited by 34 publications

(23 citation statements)

References 20 publications

(19 reference statements)

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“…AFM measurements show that the CH pattern forms during the In y Ga 1Ày As growth, as reported in other studies of relaxed In y Ga 1Ày As epilayers grown on GaAs substrates [16]. The ridges are known to originate in the formation of misfit dislocations during the In y Ga 1Ày As growth [17] and the preferable striation along the ½1 % 1 0 direction has been attributed to the anisotropy in surface diffusion length of In atoms [18]. We find that the ridges are the most pronounced for the thin Ga 1Àx Mn x As epilayers and the surface becomes smoother for thicker epilayers.…”

supporting

confidence: 78%

Enhancement of Curie temperature in Ga1−xMnxAs epilayers grown on cross-hatched InyGa1−yAs buffer layers

Maksimov

Sheu

Xiang

et al. 2004

Journal of Crystal Growth

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Relaxed In y Ga 1Ày As epilayers grown on (0 0 1) GaAs are known to exhibit a cross-hatched surface with ridges running along the [1 1 0] and ½1 % 1 0 directions. We find that Ga 1Àx Mn x As epilayers grown on such buffer layers can have as-grown Curie temperatures (T C ) that are higher than the as-grown 110 K value typical of Ga 1Àx Mn x As/GaAs heterostructures. Further, low-temperature annealing leads to only modest additional increases in T C ; contrasting with the behavior in Ga 1Àx Mn x As/GaAs where T C typically increases significantly upon annealing. Our observations suggest that the initial concentration of Mn interstitials in as-grown Ga 1Àx Mn x As /In y Ga 1Ày As heterostructures is smaller than that in as-grown Ga 1Àx Mn x As/GaAs heterostructures. We propose that strain-dependent diffusion may drive Mn interstitials from the bulk of the growing crystal to more benign locations on the ridged surface, providing a possible route towards defect-engineering in these materials. r

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supporting

confidence: 78%

Enhancement of Curie temperature in Ga1−xMnxAs epilayers grown on cross-hatched InyGa1−yAs buffer layers

Maksimov

Sheu

Xiang

et al. 2004

Journal of Crystal Growth

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“…1a. This is typical of 2D growth of lattice-mismatched epilayer and is seen in various material systems, including GaAsP/GaP and SiGe/Si [11,12]. Upon closer inspection of the line scans along the [110]-and [1-10] directions in Figs.…”

mentioning

confidence: 70%

Evolution of InAs quantum dots grown on cross‐hatch substrates

Limwongse

Panyakeow

Kanjanachuchai

2009

Phys. Status Solidi (c)

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InAs quantum dots (QDs) are grown on In0.2Ga0.8As/GaAs cross‐hatch layer by molecular beam epitaxy. The self‐assembled QDs form with the deposition of approximately 0.8 monolayer (ML) of InAs. The QDs distribute on the cross‐hatch surface unevenly: more are found along the [1‐10] crystallographic direction than the orthogonal [110] direction, while there exists even lower density of QDs on the flat areas. Height analyses indicate that QDs first form at the hatches' intersections, then they form along the [1‐10] direction, the [110] direction, and on the flat areas, respectively. This orderly evolution of QDs is attributed to the characteristic strain distribution of the cross‐hatch surface, giving rise to position‐ and orientation‐dependent critical thickness for QD formation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…Figure 2 shows that the InAs QDs form highly ordered lines along ͗011͘ for a sample that was annealed for 60 min at 620°C prior to the deposition of InAs. As was predicted by Samonji et al 15 the surface of the sample has undulations that are parallel to ͓0-11͔ as well as less noticeable ones that are parallel to ͓011͔. It has been reported that, for InGaAs/GaAs heteroepitaxy, the incorporation rate of group III atoms to the B-type step, parallel to ͓011͔, is higher than that to the A-type step, parallel to ͓0-11͔.…”

Section: Resultsmentioning

confidence: 58%

“…It has been reported that, for InGaAs/GaAs heteroepitaxy, the incorporation rate of group III atoms to the B-type step, parallel to ͓011͔, is higher than that to the A-type step, parallel to ͓0-11͔. 15 This asymmetry in adatom diffusion, implying that the surface diffusion length along ͓011͔ is longer than that along the ͓0-11͔ direction, could explain the undulations observed. These undulations provide nucleation sites for the QDs, thus facilitating alignment of the QDs.…”

Section: Resultsmentioning

confidence: 94%

Dislocation-induced spatial ordering of InAs quantum dots: Effects on optical properties

León

Chaparro

Johnson

et al. 2002

Journal of Applied Physics

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Improved optical properties of InAs quantum dots grown with an As 2 source using molecular beam epitaxy J. Appl. Phys. 100, 063107 (2006) Misfit dislocations were used to modify the surface morphology and to attain spatial ordering of quantum dots ͑QDs͒ by molecular beam epitaxy. Effects of anneal time and temperature on strain-relaxed In x Ga 1Ϫx As/GaAs layers and subsequent spatial ordering of InAs QDs were investigated. Photoluminescence ͑PL͒ and time-resolved PL was used to study the effects of increased QD positional ordering, increased QD uniformity, and their proximity to dislocation arrays on their optical properties. Narrower inhomogeneous PL broadening from the QDs ordered on dislocation arrays were observed, and differences in PL dynamics were found.

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Evolution process of cross-hatch patterns and reduction of surface roughness in (InAs)m(GaAs)n strained short-period superlattices and InGaAs alloy layers grown on GaAs

Abstract: Strain-dependent morphology of spontaneous lateral composition modulations in ( AlAs ) m ( InAs ) n shortperiod superlattices grown by molecular beam epitaxy

Cited by 34 publications

References 20 publications

Enhancement of Curie temperature in Ga1−xMnxAs epilayers grown on cross-hatched InyGa1−yAs buffer layers

Enhancement of Curie temperature in Ga1−xMnxAs epilayers grown on cross-hatched InyGa1−yAs buffer layers

Evolution of InAs quantum dots grown on cross‐hatch substrates

Dislocation-induced spatial ordering of InAs quantum dots: Effects on optical properties

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