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Selective area epitaxy of ultra-high density InGaN quantum dots by diblock copolymer lithography.

Liu G, Zhao H, Zhang J, Park JH, Mawst LJ, Tansu N - Nanoscale Res Lett (2011)

Bottom Line: The cylindrical-shaped nanopatterns were created on SiNx layers deposited on a GaN template, which provided the nanopatterning for the epitaxy of ultra-high density QD with uniform size and distribution.The InGaN/GaN QDs with density up to 8 × 1010 cm-2 are realized, which represents ultra-high dot density for highly uniform and well-controlled, nitride-based QDs, with QD diameter of approximately 22-25 nm.The photoluminescence (PL) studies indicated the importance of NH3 annealing and GaN spacer layer growth for improving the PL intensity of the SiNx-treated GaN surface, to achieve high optical-quality QDs applicable for photonics devices.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Optical Technologies, Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, PA 18015, USA. gul308@lehigh.edu.

ABSTRACT
Highly uniform InGaN-based quantum dots (QDs) grown on a nanopatterned dielectric layer defined by self-assembled diblock copolymer were performed by metal-organic chemical vapor deposition. The cylindrical-shaped nanopatterns were created on SiNx layers deposited on a GaN template, which provided the nanopatterning for the epitaxy of ultra-high density QD with uniform size and distribution. Scanning electron microscopy and atomic force microscopy measurements were conducted to investigate the QDs morphology. The InGaN/GaN QDs with density up to 8 × 1010 cm-2 are realized, which represents ultra-high dot density for highly uniform and well-controlled, nitride-based QDs, with QD diameter of approximately 22-25 nm. The photoluminescence (PL) studies indicated the importance of NH3 annealing and GaN spacer layer growth for improving the PL intensity of the SiNx-treated GaN surface, to achieve high optical-quality QDs applicable for photonics devices.

No MeSH data available.


AFM measurement using Dimension 3000 for SAE-grown InGaN/GaN QDs arrays on sample A after removal of SiNx: (a) AFM scan with the scale of 0.5 μm × 0.5 μm; (b) the corresponding height and size of the cross-sectional profiles.
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Figure 6: AFM measurement using Dimension 3000 for SAE-grown InGaN/GaN QDs arrays on sample A after removal of SiNx: (a) AFM scan with the scale of 0.5 μm × 0.5 μm; (b) the corresponding height and size of the cross-sectional profiles.

Mentions: AFM measurements on InGaN/GaN QD samples were carried out after the removal of SiNx layer to provide with direct measurements of QDs morphology. The AFM measurements of the InGaN/GaN (Sample A) were carried out using Dimension 3000, as shown in Figure 6a,b. Figure 6a shows the InGaN/GaN QDs arrays with the scale of 0.5 μm × 0.5 μm, and Figure 6b refers to the height and lateral of the cross-sectional profiles indicated in Figure 6a. The highly uniform QDs were observed from AFM measurements. The dot density was estimated to be 7.5 × 1010 cm-2 with the average height of 1.84 nm and dot diameter of about 25 nm, and these results are in good agreement with those of the nanopatterns employed in the studies. The height and the size of the cross-sectional profiles in Figure 6b indicate that the growth of the dots was well controlled, and the sample exhibits much less variations in dot size, shapes, and distributions compared to those of SK growth mode [44].


Selective area epitaxy of ultra-high density InGaN quantum dots by diblock copolymer lithography.

Liu G, Zhao H, Zhang J, Park JH, Mawst LJ, Tansu N - Nanoscale Res Lett (2011)

AFM measurement using Dimension 3000 for SAE-grown InGaN/GaN QDs arrays on sample A after removal of SiNx: (a) AFM scan with the scale of 0.5 μm × 0.5 μm; (b) the corresponding height and size of the cross-sectional profiles.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211431&req=5

Figure 6: AFM measurement using Dimension 3000 for SAE-grown InGaN/GaN QDs arrays on sample A after removal of SiNx: (a) AFM scan with the scale of 0.5 μm × 0.5 μm; (b) the corresponding height and size of the cross-sectional profiles.
Mentions: AFM measurements on InGaN/GaN QD samples were carried out after the removal of SiNx layer to provide with direct measurements of QDs morphology. The AFM measurements of the InGaN/GaN (Sample A) were carried out using Dimension 3000, as shown in Figure 6a,b. Figure 6a shows the InGaN/GaN QDs arrays with the scale of 0.5 μm × 0.5 μm, and Figure 6b refers to the height and lateral of the cross-sectional profiles indicated in Figure 6a. The highly uniform QDs were observed from AFM measurements. The dot density was estimated to be 7.5 × 1010 cm-2 with the average height of 1.84 nm and dot diameter of about 25 nm, and these results are in good agreement with those of the nanopatterns employed in the studies. The height and the size of the cross-sectional profiles in Figure 6b indicate that the growth of the dots was well controlled, and the sample exhibits much less variations in dot size, shapes, and distributions compared to those of SK growth mode [44].

Bottom Line: The cylindrical-shaped nanopatterns were created on SiNx layers deposited on a GaN template, which provided the nanopatterning for the epitaxy of ultra-high density QD with uniform size and distribution.The InGaN/GaN QDs with density up to 8 × 1010 cm-2 are realized, which represents ultra-high dot density for highly uniform and well-controlled, nitride-based QDs, with QD diameter of approximately 22-25 nm.The photoluminescence (PL) studies indicated the importance of NH3 annealing and GaN spacer layer growth for improving the PL intensity of the SiNx-treated GaN surface, to achieve high optical-quality QDs applicable for photonics devices.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Optical Technologies, Department of Electrical and Computer Engineering, Lehigh University, Bethlehem, PA 18015, USA. gul308@lehigh.edu.

ABSTRACT
Highly uniform InGaN-based quantum dots (QDs) grown on a nanopatterned dielectric layer defined by self-assembled diblock copolymer were performed by metal-organic chemical vapor deposition. The cylindrical-shaped nanopatterns were created on SiNx layers deposited on a GaN template, which provided the nanopatterning for the epitaxy of ultra-high density QD with uniform size and distribution. Scanning electron microscopy and atomic force microscopy measurements were conducted to investigate the QDs morphology. The InGaN/GaN QDs with density up to 8 × 1010 cm-2 are realized, which represents ultra-high dot density for highly uniform and well-controlled, nitride-based QDs, with QD diameter of approximately 22-25 nm. The photoluminescence (PL) studies indicated the importance of NH3 annealing and GaN spacer layer growth for improving the PL intensity of the SiNx-treated GaN surface, to achieve high optical-quality QDs applicable for photonics devices.

No MeSH data available.