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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.


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SEM image of diblock copolymer nanopatterns on SiNx with the hexagonal array of openings after the UV exposure.
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Figure 3: SEM image of diblock copolymer nanopatterns on SiNx with the hexagonal array of openings after the UV exposure.

Mentions: To investigate the surface topographies and QD morphologies, scanning electron microscope (SEM) (Hitachi 4300) and atomic force microscopy (AFM) (Dimension 3000 and Agilent 5500) measurements were performed. Figure 3 shows the SEM image of the copolymer deposited on SiNx layer after undergoing the UV radiation which would result in nanopore openings, before any active region growth. The SEM images shown in Figure 3 are similar to the processing step described in Figure 1c. The diameter of the holes in the copolymer was measured as approximately 20-25 nm, and the arrangement of the copolymer shows 2-D hexagonal-closed packed structure, although without long-range order between grain boundaries.


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)

SEM image of diblock copolymer nanopatterns on SiNx with the hexagonal array of openings after the UV exposure.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: SEM image of diblock copolymer nanopatterns on SiNx with the hexagonal array of openings after the UV exposure.
Mentions: To investigate the surface topographies and QD morphologies, scanning electron microscope (SEM) (Hitachi 4300) and atomic force microscopy (AFM) (Dimension 3000 and Agilent 5500) measurements were performed. Figure 3 shows the SEM image of the copolymer deposited on SiNx layer after undergoing the UV radiation which would result in nanopore openings, before any active region growth. The SEM images shown in Figure 3 are similar to the processing step described in Figure 1c. The diameter of the holes in the copolymer was measured as approximately 20-25 nm, and the arrangement of the copolymer shows 2-D hexagonal-closed packed structure, although without long-range order between grain boundaries.

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.


Related in: MedlinePlus