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On the phenomenon of large photoluminescence red shift in GaN nanoparticles.

Slimane AB, Najar A, Elafandy R, San-Román-Alerigi DP, Anjum D, Ng TK, Ooi BS - Nanoscale Res Lett (2013)

Bottom Line: Nanoparticles with broad tunable emission wavelength from 362 to 440 nm have been achieved by exciting the samples using the excitation power-dependent method.We attribute this large wavelength tunability to the localized potential fluctuations present within the GaN matrix and to vacancy-related surface states.Our results show that GaN NPs fabricated using this technique are promising for tunable-color-temperature white light-emitting diode applications.

View Article: PubMed Central - HTML - PubMed

Affiliation: Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia. Boon.Ooi@kaust.edu.sa.

ABSTRACT
We report on the observation of broad photoluminescence wavelength tunability from n-type gallium nitride nanoparticles (GaN NPs) fabricated using the ultraviolet metal-assisted electroless etching method. Transmission and scanning electron microscopy measurements performed on the nanoparticles revealed large size dispersion ranging from 10 to 100 nm. Nanoparticles with broad tunable emission wavelength from 362 to 440 nm have been achieved by exciting the samples using the excitation power-dependent method. We attribute this large wavelength tunability to the localized potential fluctuations present within the GaN matrix and to vacancy-related surface states. Our results show that GaN NPs fabricated using this technique are promising for tunable-color-temperature white light-emitting diode applications.

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SEM and TEM images and elemental maps. (a) SEM image of the NPs prepared using UV metal-assisted electroless etching technique and (b) TEM image of NPs. (c) Overlaid elemental maps of Ga, N, and O in red, green, and blue, respectively, acquired by EFTEM.
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Figure 1: SEM and TEM images and elemental maps. (a) SEM image of the NPs prepared using UV metal-assisted electroless etching technique and (b) TEM image of NPs. (c) Overlaid elemental maps of Ga, N, and O in red, green, and blue, respectively, acquired by EFTEM.

Mentions: Figure 1a shows the SEM image of the GaN NPs on a Si substrate in a grain-like structure having NPs with sizes ranging from 10 to 100 nm. By high-resolution TEM (Figure 1b), we observed adjoining single-crystal GaN NPs with each particle surrounded by the amorphous-like boundary. The electron energy loss spectroscopy (EELS) analysis revealed the oxygen amount to be about 20 at.%. The spatial distributions of all three constituent elements, namely Ga, N, and O, are determined and acquired using the energy-filtered TEM (EFTEM) technique (see in Figure 1c). It can be noticed from Figure 1c that the O map (blue) is mostly present in the surrounding of NPs which is in agreement with results obtained from EELS. The presence of oxygen in the nanoparticle can be explained by the finite surface oxidation of GaN simply due to the large specific surface.


On the phenomenon of large photoluminescence red shift in GaN nanoparticles.

Slimane AB, Najar A, Elafandy R, San-Román-Alerigi DP, Anjum D, Ng TK, Ooi BS - Nanoscale Res Lett (2013)

SEM and TEM images and elemental maps. (a) SEM image of the NPs prepared using UV metal-assisted electroless etching technique and (b) TEM image of NPs. (c) Overlaid elemental maps of Ga, N, and O in red, green, and blue, respectively, acquired by EFTEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3733736&req=5

Figure 1: SEM and TEM images and elemental maps. (a) SEM image of the NPs prepared using UV metal-assisted electroless etching technique and (b) TEM image of NPs. (c) Overlaid elemental maps of Ga, N, and O in red, green, and blue, respectively, acquired by EFTEM.
Mentions: Figure 1a shows the SEM image of the GaN NPs on a Si substrate in a grain-like structure having NPs with sizes ranging from 10 to 100 nm. By high-resolution TEM (Figure 1b), we observed adjoining single-crystal GaN NPs with each particle surrounded by the amorphous-like boundary. The electron energy loss spectroscopy (EELS) analysis revealed the oxygen amount to be about 20 at.%. The spatial distributions of all three constituent elements, namely Ga, N, and O, are determined and acquired using the energy-filtered TEM (EFTEM) technique (see in Figure 1c). It can be noticed from Figure 1c that the O map (blue) is mostly present in the surrounding of NPs which is in agreement with results obtained from EELS. The presence of oxygen in the nanoparticle can be explained by the finite surface oxidation of GaN simply due to the large specific surface.

Bottom Line: Nanoparticles with broad tunable emission wavelength from 362 to 440 nm have been achieved by exciting the samples using the excitation power-dependent method.We attribute this large wavelength tunability to the localized potential fluctuations present within the GaN matrix and to vacancy-related surface states.Our results show that GaN NPs fabricated using this technique are promising for tunable-color-temperature white light-emitting diode applications.

View Article: PubMed Central - HTML - PubMed

Affiliation: Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia. Boon.Ooi@kaust.edu.sa.

ABSTRACT
We report on the observation of broad photoluminescence wavelength tunability from n-type gallium nitride nanoparticles (GaN NPs) fabricated using the ultraviolet metal-assisted electroless etching method. Transmission and scanning electron microscopy measurements performed on the nanoparticles revealed large size dispersion ranging from 10 to 100 nm. Nanoparticles with broad tunable emission wavelength from 362 to 440 nm have been achieved by exciting the samples using the excitation power-dependent method. We attribute this large wavelength tunability to the localized potential fluctuations present within the GaN matrix and to vacancy-related surface states. Our results show that GaN NPs fabricated using this technique are promising for tunable-color-temperature white light-emitting diode applications.

No MeSH data available.


Related in: MedlinePlus