Atomic layer molecular beam epitaxy (Almbe) of III?V compounds: Growth modes and applications

Briones, F.; González, L.; Ruiz, A.

doi:10.1007/bf00617001

Cited by 129 publications

(41 citation statements)

References 13 publications

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“…This growth mode allows growing atomically flat GaAs epitaxial layers at low substrate temperature without thickness limitation [19]. Once the GaAs buffer was grown at low substrate temperature, T S was increased to 510ºC for growing the InAs QD: 1.7 ML of InAs were deposited by pulses of 0.1 ML of InAs at 0.05 ML/s followed by a pause of 2s under As 2 flux.…”

Section: Methodsmentioning

confidence: 99%

Improvement of InAs quantum dots optical properties in close proximity to GaAs(001) substrate surface

Martín‐Sánchez¹,

González²,

Alonso‐González³

et al. 2008

Journal of Crystal Growth

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In this work we demonstrate a growth process for obtaining high optical emission efficiency InAs/GaAs(001) quantum dots (QD) formed at short distance to the interface with the GaAs substrate. In particular, after an initial exposure of the substrate surface to long times of atomic hydrogen flux (t H up to 45 min) followed by a posterior growth of a GaAs buffer layer by atomic layer molecular beam epitaxy, both steps at low substrate temperature (T S =450 ºC), an enhancement of InAs QD optical emission efficiency is obtained, even at close proximity (3.5 nm) to the substrate interface. This process fulfils the strict requirements in terms of substrate temperature and buffer layer thickness (distance from the QD to the substrate interface) for its possible use as an optimal regrowth protocol on previously patterned GaAs substrates.

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Section: Methodsmentioning

confidence: 99%

Improvement of InAs quantum dots optical properties in close proximity to GaAs(001) substrate surface

Martín‐Sánchez¹,

González²,

Alonso‐González³

et al. 2008

Journal of Crystal Growth

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“…MBE-grown structures consist of (i) 100 nm GaAs buffer grown at 600 C, (ii) InAs QDs deposited by MBE at 0.01 ML/s at Tg growth temperatures, and (iii) a 20 nm-thick GaAs cap layer grown by atomic layer MBE at 360 C. 30 In particular, sample II has been grown with T g ¼ 530 C and 2.0 ML resulting in a QD density of 25 QDs/lm 2 , while for the sample I the temperature was increased to 535 C and 2.50 ML to allow for a reduction of the QD density to 16.5 QDs/lm 2 and a change in QD size distribution (see Figs. 1(b) and 1(c)).…”

Section: Samples and Experimental Set-upmentioning

confidence: 99%

Size dependent carrier thermal escape and transfer in bimodally distributed self assembled InAs/GaAs quantum dots

Muñoz‐Matutano

Suárez²,

Canet‐Ferrer

et al. 2012

Journal of Applied Physics

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We have investigated the temperature dependent recombination dynamics in two bimodally distributed InAs self assembled quantum dots samples. A rate equations model has been implemented to investigate the thermally activated carrier escape mechanism which changes from exciton-like to uncorrelated electron and hole pairs as the quantum dot size varies. For the smaller dots, we find a hot exciton thermal escape process. We evaluated the thermal transfer process between quantum dots by the quantum dot density and carrier escape properties of both samples.

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“…Then, the substrate temperature T s is decreased to 500°C and the Ga shutter is opened during 10 s with the Ga cell, providing a flux equivalent to the growth of GaAs at 1 ML/ s. During this time, the arsenic cell is opened periodically during 0.2 s every 0.8 s. The beam equivalent pressure ͑BEP͒ of As 4 is fixed during the process to 5 ϫ 10 −7 Torr. This process is a kind of arsenic-debt atomic layer molecular beam epitaxy growth 14 and results in Ga droplets spread all over the surface with a density of 2.5ϫ 10 8 cm −2 . The sample is then annealed during 6 min at the same substrate temperature and As 4 pressure.…”

mentioning

confidence: 99%

Formation and optical characterization of single InAs quantum dots grown on GaAs nanoholes

Alonso‐González¹,

Alén²,

Fuster³

et al. 2007

Applied Physics Letters

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We present a study of the structural and optical properties of InAs quantum dots formed in a low density template of nanoholes fabricated by droplet epitaxy on GaAs ͑001͒. The growth conditions used here promote the formation of isolated quantum dots only inside the templated nanoholes. Due to the good optical quality and low density of these nanostructures, their ensemble and individual emission properties could be investigated and related to the particular growth method employed and the quantum dot morphology. © 2007 American Institute of Physics. ͓DOI: 10.1063/1.2799736͔ New nanoelectronics and quantum information perspectives require the ability of growing nanostructures with control in size and spatial location. In particular, for the application of quantum devices based in single quantum dots 1,2 ͑QDs͒ as, for instance, single photon emitters, it is necessary to combine strategies that would permit precise location of a single nanostructure presenting at the same time high optical quality. [3][4][5][6] With this aim, a quite wide-spread strategy to overcome the randomly positioning of self-assembled nanostructures is based on the use of patterned substrates to create preferential nucleation sites that define the position and size of the nanostructures. In particular, highly ordered arrays of QDs have been already obtained using different lithographic approaches followed by an appropriate regrowth process. 5,7,8 In this situation, the droplet epitaxy has revealed itself as a potential technique to achieve templates for localization of nanostructures with high optical quality in latticemismatched heteroepitaxial systems. 9 This technique has been mainly developed in GaAs based systems and basically consists of the supply of a certain amount of Ga during growth to form metallic droplets on the surface, which are later transformed into crystalline GaAs under arsenic atmosphere. Under certain experimental conditions, the crystallization process leads to the formation of specific structures containing nanoholes that act as preferential sites for InAs QD nucleation upon further InAs deposition. 10 The density of nanoholes corresponds to that of the droplets, being possible to obtain QD densities as low as 10 7 cm −2 . 11 The size of these nanostructures is related to the amount of InAs filling the nanoholes, with independence of their density, as opposed to the QD formation by self-assembling processes. This fact is especially interesting for applications based on a single QD. Furthermore, in coincidence with other lithographic techniques, 12 a different number of QD per nanohole can also be obtained. 13 In this situation, one advantage of the droplet epitaxy technique is that it can provide nanotemplates for QD formation without the need of growing thick buffer layers to avoid the influence of residual contamination from the fabrication process on the optical properties of the nanostructures.This work deals with the structural and optical characterization of InAs QDs formed in a template of 2.4 ϫ 10 8 cm −2 nano...

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Atomic layer molecular beam epitaxy (Almbe) of III?V compounds: Growth modes and applications

Cited by 129 publications

References 13 publications

Improvement of InAs quantum dots optical properties in close proximity to GaAs(001) substrate surface

Improvement of InAs quantum dots optical properties in close proximity to GaAs(001) substrate surface

Size dependent carrier thermal escape and transfer in bimodally distributed self assembled InAs/GaAs quantum dots

Formation and optical characterization of single InAs quantum dots grown on GaAs nanoholes

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