Long-wavelength light emission from InAs quantum dots covered by GaAsSb grown on GaAs substrates

Akahane, Kouichi; Yamamoto, Naokatsu; Ohtani, Naoki

doi:10.1016/j.physe.2003.11.016

Cited by 71 publications

(47 citation statements)

References 6 publications

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“…3 shows the 15 K PL spectra of the samples in the series with increasing amount of Sb in the capping layer (A to F). As already reported, [1][2][3][4][5] by gradually increasing the Sb content, the emission wavelength of the QDs can be redshifted. The red shift is due to the reduction in strain, 1-5 the increase in QD height, 18 and the transition to a type-II band alignment in the valence band, with the hole wavefunction being localized out of the QD, in the GaAsSb capping layer.…”

Section: A Determination Of the Sb Contentsupporting

confidence: 61%

“…A thin ($5 nm) GaAsSb capping layer allows extending the emission wavelength of InAs QDs grown on GaAs substrates to the 1.55 lm region. [1][2][3][4][5] Additionally, the room temperature photoluminescence (PL) of the InAs QDs has been shown to be improved (increased integrated intensity and reduced inhomogeneous broadening) by the GaAsSb capping layer with moderate Sb contents. 18 This improvement has been attributed to an increased QD height due to reduced In-Ga intermixing during the capping process, 18 which would increase carrier localization and electron-hole wavefunction overlap.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the modified optical properties and band structure of GaAs1−xSbx-capped InAs/GaAs quantum dots

Ulloa

Llorens²,

Moral

et al. 2012

Journal of Applied Physics

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Pronounced Purcell enhancement of spontaneous emission in CdTe/ZnTe quantum dots embedded in micropillar cavities Appl. Phys. Lett. 101, 132105 (2012) Fabrication and photoluminescence of SiC quantum dots stemming from 3C, 6H, and 4H polytypes of bulk SiC Appl. Phys. Lett. 101, 131906 (2012) Radiative transitions in stacked type-II ZnMgTe quantum dots embedded in ZnSe J. Appl. Phys. 112, 063521 (2012) Anomalous temperature dependence of photoluminescence in self-assembled InGaN quantum dots Appl. Phys. Lett. 101, 131101 (2012) Optical properties of multi-stacked InGaAs/GaNAs quantum dot solar cell fabricated on GaAs (311)B substrate J. Appl. Phys. 112, 064314 (2012) Additional information on J. Appl. Phys. The origin of the modified optical properties of InAs/GaAs quantum dots (QD) capped with a thin GaAs 1Àx Sb x layer is analyzed in terms of the band structure. To do so, the size, shape, and composition of the QDs and capping layer are determined through cross-sectional scanning tunnelling microscopy and used as input parameters in an 8 Â 8 kÁp model. As the Sb content is increased, there are two competing effects determining carrier confinement and the oscillator strength: the increased QD height and reduced strain on one side and the reduced QD-capping layer valence band offset on the other. Nevertheless, the observed evolution of the photoluminescence (PL) intensity with Sb cannot be explained in terms of the oscillator strength between ground states, which decreases dramatically for Sb > 16%, where the band alignment becomes type II with the hole wavefunction localized outside the QD in the capping layer. Contrary to this behaviour, the PL intensity in the type II QDs is similar (at 15 K) or even larger (at room temperature) than in the type I Sb-free reference QDs. This indicates that the PL efficiency is dominated by carrier dynamics, which is altered by the presence of the GaAsSb capping layer. In particular, the presence of Sb leads to an enhanced PL thermal stability. From the comparison between the activation energies for thermal quenching of the PL and the modelled band structure, the main carrier escape mechanisms are suggested. In standard GaAs-capped QDs, escape of both electrons and holes to the GaAs barrier is the main PL quenching mechanism. For small-moderate Sb (<16%) for which the type I band alignment is kept, electrons escape to the GaAs barrier and holes escape to the GaAsSb capping layer, where redistribution and retraping processes can take place. For Sb contents above 16% (type-II region), holes remain in the GaAsSb layer and the escape of electrons from the QD to the GaAs barrier is most likely the dominant PL quenching mechanism. This means that electrons and holes behave dynamically as uncorrelated pairs in both the type-I and type-II structures. V C 2012 American Institute of Physics.[http://dx

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Section: A Determination Of the Sb Contentsupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Analysis of the modified optical properties and band structure of GaAs1−xSbx-capped InAs/GaAs quantum dots

Ulloa

Llorens²,

Moral

et al. 2012

Journal of Applied Physics

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“…The most common capping materials used for the reduction of strain inside dots are InGaAs (Dasika et al, 2009;Kim et al, 2003) and GaAsSb (Haxha et al, 2009;Bozkhurt et al, 2011;Ulloa et al, 2007;Akahane et al, 2004), sometimes InAlAs or some combination of these materials is used (Liu et al, 2005;Kong et al,2008). Strain reducing layers covering InAs dots are used to shift the emission wavelength to 1.3 µm and 1.55 µm, typical of optical fibre communication.…”

Section: Strain Reducing Capping Layersmentioning

confidence: 99%

Capping of InAs/GaAs Quantum Dots for GaAs Based Lasers

Hospodková¹

2012

Quantum Dots - A Variety of New Applications

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“…Self-assembled InAs(Sb)GaAs quantum dots (QDs) heterostructures have received much attention since they are able to emit at 1.3-1.55 µm even at room temperature [1,2]. This emission range is useful for telecommunication lasers and opto-electronic applications.…”

Section: Introductionmentioning

confidence: 99%

Compositional analysis of InAs-GaAs-GaSb heterostructures by Low-Loss Electron Energy Loss Spectroscopy

Beltrán

Ben

Sánchez

et al. 2013

J. Phys.: Conf. Ser.

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Long-wavelength light emission from InAs quantum dots covered by GaAsSb grown on GaAs substrates

Cited by 71 publications

References 6 publications

Analysis of the modified optical properties and band structure of GaAs1−xSbx-capped InAs/GaAs quantum dots

Analysis of the modified optical properties and band structure of GaAs1−xSbx-capped InAs/GaAs quantum dots

Capping of InAs/GaAs Quantum Dots for GaAs Based Lasers

Compositional analysis of InAs-GaAs-GaSb heterostructures by Low-Loss Electron Energy Loss Spectroscopy

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