Limits...
Growth of Low-Density Vertical Quantum Dot Molecules with Control in Energy Emission.

Alonso-González P, González L, Martín-Sánchez J, González Y, Fuster D, Sales DL, Hernández-Maldonado D, Herrera M, Molina SI - Nanoscale Res Lett (2010)

Bottom Line: In this work, we present results on the formation of vertical molecule structures formed by two vertically aligned InAs quantum dots (QD) in which a deliberate control of energy emission is achieved.In this way, either symmetric or asymmetric vertically coupled structures can be obtained.As a characteristic when using a droplet epitaxy patterning process, the density of quantum dot molecules finally obtained is low enough (2 × 10(8) cm(-2)) to permit their integration as active elements in advanced photonic devices where spectroscopic studies at the single nanostructure level are required.

View Article: PubMed Central - HTML - PubMed

ABSTRACT
In this work, we present results on the formation of vertical molecule structures formed by two vertically aligned InAs quantum dots (QD) in which a deliberate control of energy emission is achieved. The emission energy of the first layer of QD forming the molecule can be tuned by the deposition of controlled amounts of InAs at a nanohole template formed by GaAs droplet epitaxy. The QD of the second layer are formed directly on top of the buried ones by a strain-driven process. In this way, either symmetric or asymmetric vertically coupled structures can be obtained. As a characteristic when using a droplet epitaxy patterning process, the density of quantum dot molecules finally obtained is low enough (2 × 10(8) cm(-2)) to permit their integration as active elements in advanced photonic devices where spectroscopic studies at the single nanostructure level are required.

No MeSH data available.


Photoluminescence spectra of the three different vertical QD pairs studied in this work. Black, red, and blue lines correspond to samples in which the QD1 nanostructure layer is formed by depositing 1.2, 1.4, and 1.5 MLof InAs, respectively. The arrows in the figure point out the two families of QD formed in each sample
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2991188&req=5

Figure 3: Photoluminescence spectra of the three different vertical QD pairs studied in this work. Black, red, and blue lines correspond to samples in which the QD1 nanostructure layer is formed by depositing 1.2, 1.4, and 1.5 MLof InAs, respectively. The arrows in the figure point out the two families of QD formed in each sample

Mentions: Concerning the optical properties of these paired nanostructures, Fig. 3 shows the PL signal for the three different cases. In particular, the black, red, and blue lines in the figure correspond to QD pair structures obtained by depositing 1.2, 1.4, and 1.5 ML of InAs for the formation of QD1 layer, respectively. The presence of two main peaks can be observed in all the cases. The evolution of these two PL peaks with increasing excitation power (not shown) reveals that they correspond to two different QD families, as they do not show any relative saturation effects corresponding to one QD family with ground and excited states. Combining these optical emission results with those obtained by TEM structural analysis, it can be established a direct correspondence of the different emission energies to the recombination of carriers at the upper and lower QD layers of the molecule structure. Figure 4a shows as filled areas the three different PL emissions that would correspond to the QD1 family for the three different QD paired structures. As expected from previous results [12], the effect of the different amount of InAs deposited in the first layer of nanostructures permits the emission energy of the QD1 to be tuned in a wide range.


Growth of Low-Density Vertical Quantum Dot Molecules with Control in Energy Emission.

Alonso-González P, González L, Martín-Sánchez J, González Y, Fuster D, Sales DL, Hernández-Maldonado D, Herrera M, Molina SI - Nanoscale Res Lett (2010)

Photoluminescence spectra of the three different vertical QD pairs studied in this work. Black, red, and blue lines correspond to samples in which the QD1 nanostructure layer is formed by depositing 1.2, 1.4, and 1.5 MLof InAs, respectively. The arrows in the figure point out the two families of QD formed in each sample
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2991188&req=5

Figure 3: Photoluminescence spectra of the three different vertical QD pairs studied in this work. Black, red, and blue lines correspond to samples in which the QD1 nanostructure layer is formed by depositing 1.2, 1.4, and 1.5 MLof InAs, respectively. The arrows in the figure point out the two families of QD formed in each sample
Mentions: Concerning the optical properties of these paired nanostructures, Fig. 3 shows the PL signal for the three different cases. In particular, the black, red, and blue lines in the figure correspond to QD pair structures obtained by depositing 1.2, 1.4, and 1.5 ML of InAs for the formation of QD1 layer, respectively. The presence of two main peaks can be observed in all the cases. The evolution of these two PL peaks with increasing excitation power (not shown) reveals that they correspond to two different QD families, as they do not show any relative saturation effects corresponding to one QD family with ground and excited states. Combining these optical emission results with those obtained by TEM structural analysis, it can be established a direct correspondence of the different emission energies to the recombination of carriers at the upper and lower QD layers of the molecule structure. Figure 4a shows as filled areas the three different PL emissions that would correspond to the QD1 family for the three different QD paired structures. As expected from previous results [12], the effect of the different amount of InAs deposited in the first layer of nanostructures permits the emission energy of the QD1 to be tuned in a wide range.

Bottom Line: In this work, we present results on the formation of vertical molecule structures formed by two vertically aligned InAs quantum dots (QD) in which a deliberate control of energy emission is achieved.In this way, either symmetric or asymmetric vertically coupled structures can be obtained.As a characteristic when using a droplet epitaxy patterning process, the density of quantum dot molecules finally obtained is low enough (2 × 10(8) cm(-2)) to permit their integration as active elements in advanced photonic devices where spectroscopic studies at the single nanostructure level are required.

View Article: PubMed Central - HTML - PubMed

ABSTRACT
In this work, we present results on the formation of vertical molecule structures formed by two vertically aligned InAs quantum dots (QD) in which a deliberate control of energy emission is achieved. The emission energy of the first layer of QD forming the molecule can be tuned by the deposition of controlled amounts of InAs at a nanohole template formed by GaAs droplet epitaxy. The QD of the second layer are formed directly on top of the buried ones by a strain-driven process. In this way, either symmetric or asymmetric vertically coupled structures can be obtained. As a characteristic when using a droplet epitaxy patterning process, the density of quantum dot molecules finally obtained is low enough (2 × 10(8) cm(-2)) to permit their integration as active elements in advanced photonic devices where spectroscopic studies at the single nanostructure level are required.

No MeSH data available.