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Lateral Ordering of InAs Quantum Dots on Cross-hatch Patterned GaInP.

Hakkarainen T, Schramm A, Tukiainen A, Ahorinta R, Toikkanen L, Guina M - Nanoscale Res Lett (2010)

Bottom Line: We report the use of partially relaxed tensile as well as compressively strained GaInP layers for lateral ordering of InAs quantum dots with the aid of misfit dislocation networks.The QD-ordering properties of compressive GaInP are found to be very similar with respect to the use of compressive GaInAs, while a significantly stronger ordering of QDs was observed on tensile GaInP.Furthermore, we observed a change of the major type of dislocation in GaInP layers as the growth temperature was modified.

View Article: PubMed Central - HTML - PubMed

Affiliation: Optoelectronics Research Centre, Tampere University of Technology, Korkeakoulunkatu 3, 33720 Tampere, Finland.

ABSTRACT
We report the use of partially relaxed tensile as well as compressively strained GaInP layers for lateral ordering of InAs quantum dots with the aid of misfit dislocation networks. The strained layers and the InAs QDs were characterized by means of atomic force microscopy, scanning electron microscopy, and X-ray reciprocal space mapping. The QD-ordering properties of compressive GaInP are found to be very similar with respect to the use of compressive GaInAs, while a significantly stronger ordering of QDs was observed on tensile GaInP. Furthermore, we observed a change of the major type of dislocation in GaInP layers as the growth temperature was modified.

No MeSH data available.


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SEM pictures (3.5 μm × 3.5 μm) of QD chains on 60-nm partially relaxed GaInP and GaInAs layers. Figures a–d correspond to samples A–D, respectively. The layer material and growth temperature of each sample are indicated in the figure
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Figure 2: SEM pictures (3.5 μm × 3.5 μm) of QD chains on 60-nm partially relaxed GaInP and GaInAs layers. Figures a–d correspond to samples A–D, respectively. The layer material and growth temperature of each sample are indicated in the figure

Mentions: Figure 2 shows SEM pictures illustrating the ordering of QDs on CS and TS layers. On the CS layers (Fig. 2a–2c), the QDs are gathered on MDs, but the ordering is relatively weak. However, on the TS layer (Fig. 2d), the QD accumulation on the MDs differs with respect to the CS layers. On TS layers, the QDs on the MDs are ordered in narrow single-dot wide chains. Furthermore, according to the quantitative data extracted from the AFM pictures and summarized in Table 1, the height and density of the QDs depend on the properties of the strained layer below them; compared to the TS-Ga0.66In0.34P, the QDs on the CS samples are larger and less dense. This can be explained by a reduction of the critical InAs coverage for QD formation due to the compressive strain of the underlying Ga0.38In0.62P or Ga0.85In0.15As layer.


Lateral Ordering of InAs Quantum Dots on Cross-hatch Patterned GaInP.

Hakkarainen T, Schramm A, Tukiainen A, Ahorinta R, Toikkanen L, Guina M - Nanoscale Res Lett (2010)

SEM pictures (3.5 μm × 3.5 μm) of QD chains on 60-nm partially relaxed GaInP and GaInAs layers. Figures a–d correspond to samples A–D, respectively. The layer material and growth temperature of each sample are indicated in the figure
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2991205&req=5

Figure 2: SEM pictures (3.5 μm × 3.5 μm) of QD chains on 60-nm partially relaxed GaInP and GaInAs layers. Figures a–d correspond to samples A–D, respectively. The layer material and growth temperature of each sample are indicated in the figure
Mentions: Figure 2 shows SEM pictures illustrating the ordering of QDs on CS and TS layers. On the CS layers (Fig. 2a–2c), the QDs are gathered on MDs, but the ordering is relatively weak. However, on the TS layer (Fig. 2d), the QD accumulation on the MDs differs with respect to the CS layers. On TS layers, the QDs on the MDs are ordered in narrow single-dot wide chains. Furthermore, according to the quantitative data extracted from the AFM pictures and summarized in Table 1, the height and density of the QDs depend on the properties of the strained layer below them; compared to the TS-Ga0.66In0.34P, the QDs on the CS samples are larger and less dense. This can be explained by a reduction of the critical InAs coverage for QD formation due to the compressive strain of the underlying Ga0.38In0.62P or Ga0.85In0.15As layer.

Bottom Line: We report the use of partially relaxed tensile as well as compressively strained GaInP layers for lateral ordering of InAs quantum dots with the aid of misfit dislocation networks.The QD-ordering properties of compressive GaInP are found to be very similar with respect to the use of compressive GaInAs, while a significantly stronger ordering of QDs was observed on tensile GaInP.Furthermore, we observed a change of the major type of dislocation in GaInP layers as the growth temperature was modified.

View Article: PubMed Central - HTML - PubMed

Affiliation: Optoelectronics Research Centre, Tampere University of Technology, Korkeakoulunkatu 3, 33720 Tampere, Finland.

ABSTRACT
We report the use of partially relaxed tensile as well as compressively strained GaInP layers for lateral ordering of InAs quantum dots with the aid of misfit dislocation networks. The strained layers and the InAs QDs were characterized by means of atomic force microscopy, scanning electron microscopy, and X-ray reciprocal space mapping. The QD-ordering properties of compressive GaInP are found to be very similar with respect to the use of compressive GaInAs, while a significantly stronger ordering of QDs was observed on tensile GaInP. Furthermore, we observed a change of the major type of dislocation in GaInP layers as the growth temperature was modified.

No MeSH data available.


Related in: MedlinePlus