Atomic-scale structure and photoluminescence of InAs quantum dots in GaAs and AlAs

Offermans, P.; Koenraad, PM Paul; Wolter, JH Joachim; Pierz, K.; Roy, Mervyn; Maksym, P. A.

doi:10.1103/physrevb.72.165332

Cited by 81 publications

(76 citation statements)

References 35 publications

(43 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…5.24). This is the same non-uniform In composition that we found in section 5.3 in GaAs-capped InAs/GaAs QDs [73] and similar to what has been previously proposed in [26]. It is attributed to In-Ga intermixing.…”

Section: Figure 523 (A) Topography Image Of the Gaassb Capping Layersupporting

confidence: 72%

“…In particular, InAs QDs grown on GaAs are larger than those grown on AlAs, and the In gradients inside the dot from bottom to top have opposite signs (increasing in InAs/GaAs QDs and decreasing in InAs/AlAs QDs) [73]. These differences are mainly due to the reduced mobility of In in AlAs due to the stronger Al-In bond strength.…”

Section: Discussionmentioning

confidence: 87%

“…We studied the effect of the host material by analysing the segregation of InAs WLs grown in the AlAs barriers of sample C, and comparing this to the segregation of InAs WLs grown, under the same growth conditions, in a GaAs matrix, ft has been shown that QD formation in the InAs/AlAs system is kinetically limited due to a reduced lateral In migration on the AlAs surface, because of the larger Al-In bond strength [36]. In the next section the marked differences in the structural properties of the dots grown in GaAs and AlAs will be discussed [37]. Figure 5.12 shows the averaged measured and fitted relaxation profiles.…”

Section: Formation Of the Wetting Layermentioning

confidence: 99%

See 2 more Smart Citations

InAs Quantum Dot Formation Studied at the Atomic Scale by Cross-sectional Scanning Tunnelling Microscopy

Ulloa

Offermans

Koenraad

2008

Handbook of Self Assembled Semiconductor Nanostructures for Novel Devices in Photonics and Electronics

Self Cite

View full text Add to dashboard Cite

Introduction Quantum dot formationSelf-assembled quantum dots (QDs) have attracted much attention in the last years [1,2]. These nanostructures are very interesting from a scientific point of view because they form nearly ideal zero-dimensional systems in which quantum confinement effects become very important. These unique properties also make them very interesting from a technological point of view. For example, InAs QDs are employed in QD lasers [3,4], single electron transistors [5], midinfrared detectors [6,7], single-photon sources [8,9], etc. InAs QDs are commonly created by the Stranski-Krastanov growth mode when InAs is deposited on a substrate with a bigger lattice constant, like GaAs or InP [10]. Above a certain critical thickness of InAs, three-dimensional islands are spontaneously formed on top of a wetting layer (WL) to reduce the strain energy. Once created, the QDs are subsequently capped, a step which is required for any device application.For any application based on InAs QDs, an accurate control of their electronic properties is required. The electron and hole states in the dot are very sensitive to the QD size, shape and composition (as well as to the surrounding material), and therefore an accurate control of the QD structural properties is necessary for applications. This explains the strong effort dedicated in the last years to the structural characterization of QDs [11], which is essential in order to have a deep understanding of the QD formation process. Although a lot of effort has been dedicated to study surface QDs, there are relatively few studies focused on the effect of the capping process [12][13][14][15][16][17][18][19][20]. Some of these studies have already shown significant differences in size, shape and composition between uncapped and capped QDs. For example, an important collapse of the QD height has been reported for InAs/GaAs QDs capped with GaAs [14,15,[17][18][19], revealing the big influence of the capping process on the structural properties of the QDs. Indeed, critical issues affecting the dot take place during capping like dot decomposition, intermixing, segregation, As/P exchange and composition modulation in the capping layer. This means that the real buried QDs must be studied in order to understand the complete QD formation process. Cross-sectional scanning tunnelling microscopy is an especially useful technique for this purpose, because it allows the structure of the capped dots at the atomic scale to be assessed. Cross-sectional scanning tunnelling microscopy (X-STM)The scanning tunnelling microscope is part of the family of scanning probe microscopes, which are able to provide direct real space information of a physical property at the atomic scale. This

show abstract

Section: Figure 523 (A) Topography Image Of the Gaassb Capping Layersupporting

confidence: 72%

Section: Discussionmentioning

confidence: 87%

Section: Formation Of the Wetting Layermentioning

confidence: 99%

See 1 more Smart Citation

InAs Quantum Dot Formation Studied at the Atomic Scale by Cross-sectional Scanning Tunnelling Microscopy

Ulloa

Offermans

Koenraad

2008

Handbook of Self Assembled Semiconductor Nanostructures for Novel Devices in Photonics and Electronics

Self Cite

View full text Add to dashboard Cite

show abstract

“…to a uniform elemental distribution [33]. Similar experimental evidence was also reported for capped InGaAs/GaAs(001) islands [28][29][30]. This analogy points to some generality in the occurrence of chemical configurations featuring QDs centres enriched in the deposited material, as opposed to highly intermixed peripheries.…”

Section: Experimental Evidence For Kinetic Limitations: Islands With supporting

confidence: 63%

“…Following this idea the detailed chemical profile in the heterostructures has been inferred from atomically resolved geometrical inhomogeneities. Interesting results have been achieved by cross-sectional scanning tunnelling microscopy (XSTM) [28][29][30] or X-ray diffraction (XRD) mapping [31]. A very promising approach is based on the selective chemical etching of the samples followed by surface imaging (e.g.…”

Section: Introductionmentioning

confidence: 99%

Alloying of self-organized semiconductor 3D islands

Ratto

Costantini

Rastelli

et al. 2006

Journal of Experimental Nanoscience

View full text Add to dashboard Cite

We present a short review of alloying in uncapped self-organized semiconductor heteronanostructures. Our aim is to provide a logical guide through the main concepts proposed in recent scientific debates. In particular, we focus on the issue of mapping the chemical composition within individual germanium quantum dots grown on silicon surfaces, a widely studied model system with high technological potential. We discuss the different experimental results reported so far in the literature, along with the main theories suggested for their rationalization. In particular, we expand on the interplay of competing factors, including thermodynamic considerations, strain relaxation and kinetic limitations. Finally, we propose a possible pathway towards a unifying picture, with the intention to motivate further research on this topic.

show abstract

Vermessung einzelner Nanoinseln. Bestimmung von Halbleiterstrukturen mit Röntgenbeugung

Stangl

2009

Physik in unserer Zeit

View full text Add to dashboard Cite

Deshalb sucht die Forschung nach alternativen Möglichkeiten, um schnellere Bauteile herzustellen. Eine davon beruht auf gezielten Materialverspannungen, eine andere auf der Verwendung von Legierungen. Beide Ansätze sind auch kombinierbar. Das Prinzip ist in beiden Fällen ähnlich. Die Schaltzeit eines Bauteils hängt von der Strecke ab, die ein Ladungsteilchen -im Halbleiter ein Elektron oder Loch -durchlaufen muss, sowie von seiner Geschwindigkeit. Letztere wird vom angelegten elektrischen Feld und von der Beweglichkeit des Teilchens in seiner Umgebung bestimmt, etwa eines Elektrons im Halbleiterkristall. Diese Beweglichkeit hängt vor allem von der effektiven Masse der Ladungsträger ab. Die effektive Masse, also die Trägheit des Teilchens gegenüber Beschleunigung im elektrischen Feld, wird nicht allein von der Masse des freien Teilchens bestimmt, sondern auch stark von seinen Wechselwirkungen mit dem Atomgitter, das es durchquert. 46 | Phys. Unserer Zeit | 1/2009 (40) Röntgenstrahlen mit dem Wellenvektor k i werden mit einem Satz refraktiver Röntgenlinsen auf einen kleinen Bereich der Probe fokussiert, die gestreute Strahlung k f nimmt ein CCD-Detektor auf.

show abstract

Atomic-scale structure and photoluminescence of InAs quantum dots in GaAs and AlAs

Cited by 81 publications

References 35 publications

InAs Quantum Dot Formation Studied at the Atomic Scale by Cross-sectional Scanning Tunnelling Microscopy

InAs Quantum Dot Formation Studied at the Atomic Scale by Cross-sectional Scanning Tunnelling Microscopy

Alloying of self-organized semiconductor 3D islands

Vermessung einzelner Nanoinseln. Bestimmung von Halbleiterstrukturen mit Röntgenbeugung

Contact Info

Product

Resources

About