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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.


MOCVD process flow of InGaN/GaN QDs SAE with dielectric patterns defined by the self-assembled diblock copolymer.
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Figure 1: MOCVD process flow of InGaN/GaN QDs SAE with dielectric patterns defined by the self-assembled diblock copolymer.

Mentions: The fabrication process consists of nano-template preparation by diblock copolymer lithography and SAE by MOCVD. Figure 1a-f shows the schematics of the fabrication process flow for the SAE-QDs defined by diblock copolymer approach. The growth of 3-μm GaN template on the c-plane sapphire substrate was carried out by employing MOCVD. The growths of the GaN templates were carried out by employing etch-back and recovery process with 30-nm low-temperature buffer layer [1,7], and the growths of high-temperature GaN layers were carried out at a temperature of 1080°C. Subsequently (Figure 1a), 10 nm SiNx was deposited on the sample by plasma-enhanced chemical vapor deposition and followed by NH3 annealing at a temperature of 800°C for 20 min to increase the adhesion of SiNx on GaN template.


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)

MOCVD process flow of InGaN/GaN QDs SAE with dielectric patterns defined by the self-assembled diblock copolymer.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: MOCVD process flow of InGaN/GaN QDs SAE with dielectric patterns defined by the self-assembled diblock copolymer.
Mentions: The fabrication process consists of nano-template preparation by diblock copolymer lithography and SAE by MOCVD. Figure 1a-f shows the schematics of the fabrication process flow for the SAE-QDs defined by diblock copolymer approach. The growth of 3-μm GaN template on the c-plane sapphire substrate was carried out by employing MOCVD. The growths of the GaN templates were carried out by employing etch-back and recovery process with 30-nm low-temperature buffer layer [1,7], and the growths of high-temperature GaN layers were carried out at a temperature of 1080°C. Subsequently (Figure 1a), 10 nm SiNx was deposited on the sample by plasma-enhanced chemical vapor deposition and followed by NH3 annealing at a temperature of 800°C for 20 min to increase the adhesion of SiNx on GaN template.

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.