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Enhancement of electroluminescence from embedded Si quantum dots/SiO2multilayers film by localized-surface-plasmon and surface roughening.

Li W, Wang S, Hu M, He S, Ge P, Wang J, Guo YY, Zhaowei L - Sci Rep (2015)

Bottom Line: The result shows that electroluminescence intensity was significantly enhanced.And, the turn-on voltage of the luminescent device was reduced to 3 V.The other factors were the improved absorption of excitation light and the increase of light extraction ratio by surface roughening structures.

View Article: PubMed Central - PubMed

Affiliation: 1] College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, 210003 China [2] Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province, Nanjing 210023, Jiangsu, China [3] Department of Electrical and Computer Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0407, USA.

ABSTRACT
In this paper, we prepared a novel structure to enhance the electroluminescence intensity from Si quantum dots/SiO2multilayers. An amorphous Si/SiO2 multilayer film was fabricated by plasma-enhanced chemical vapor deposition on a Pt nanoparticle (NP)-coated Si nanopillar array substrate. By thermal annealing, an embedded Si quantum dot (QDs)/SiO2 multilayer film was obtained. The result shows that electroluminescence intensity was significantly enhanced. And, the turn-on voltage of the luminescent device was reduced to 3 V. The enhancement of the light emission is due to the resonance coupling between the localized-surface-plasmon (LSP) of Pt NPs and the band-gap emission of Si QDs/SiO2 multilayers. The other factors were the improved absorption of excitation light and the increase of light extraction ratio by surface roughening structures. These excellent characteristics are promising for silicon-based light-emitting applications.

No MeSH data available.


The reflection spectra for flat and nano-patterned Si substrates.
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f7: The reflection spectra for flat and nano-patterned Si substrates.

Mentions: Another possible explanation for the EL enhancement factor would be the improved surface reflection by Si nanopillars as surface roughening structures. From Erchak’s paper, only ( is the effective refraction index) of light can be extracted from the top31. Considering the index of Si and SiO2, which is about 3.4 and 1.5, it can be estimated that the light escaping from the flat sample without Pt NPs-coated Si nanopillar is 8.3%. As can be seen in Fig. 2, the Si nanopillars have a cone shape, which causes a gradually changing reflective index from top to bottom. And then, the is reduced in the samples with Pt NPs-coated Si nanopillar, which leads to much more light emission. Figure 7 shows the reflection spectra for flat and nano-patterned Si substrates. It is shown that the reflectivity from the front surface of flat Si substrate is above 50% in the whole measurement range. And, it is interesting to find that the light reflection from the front surface is obviously suppressed for the nano-patterned samples, indicating the anti-reflection characteristics for nano-patterned Si substrates. It has been reported enhanced optical absorption was achieved from the Si-based nano-cone or nano-pillar structures and the antireflection32. So the light extraction efficiency can be significantly improved by surface roughing.


Enhancement of electroluminescence from embedded Si quantum dots/SiO2multilayers film by localized-surface-plasmon and surface roughening.

Li W, Wang S, Hu M, He S, Ge P, Wang J, Guo YY, Zhaowei L - Sci Rep (2015)

The reflection spectra for flat and nano-patterned Si substrates.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490393&req=5

f7: The reflection spectra for flat and nano-patterned Si substrates.
Mentions: Another possible explanation for the EL enhancement factor would be the improved surface reflection by Si nanopillars as surface roughening structures. From Erchak’s paper, only ( is the effective refraction index) of light can be extracted from the top31. Considering the index of Si and SiO2, which is about 3.4 and 1.5, it can be estimated that the light escaping from the flat sample without Pt NPs-coated Si nanopillar is 8.3%. As can be seen in Fig. 2, the Si nanopillars have a cone shape, which causes a gradually changing reflective index from top to bottom. And then, the is reduced in the samples with Pt NPs-coated Si nanopillar, which leads to much more light emission. Figure 7 shows the reflection spectra for flat and nano-patterned Si substrates. It is shown that the reflectivity from the front surface of flat Si substrate is above 50% in the whole measurement range. And, it is interesting to find that the light reflection from the front surface is obviously suppressed for the nano-patterned samples, indicating the anti-reflection characteristics for nano-patterned Si substrates. It has been reported enhanced optical absorption was achieved from the Si-based nano-cone or nano-pillar structures and the antireflection32. So the light extraction efficiency can be significantly improved by surface roughing.

Bottom Line: The result shows that electroluminescence intensity was significantly enhanced.And, the turn-on voltage of the luminescent device was reduced to 3 V.The other factors were the improved absorption of excitation light and the increase of light extraction ratio by surface roughening structures.

View Article: PubMed Central - PubMed

Affiliation: 1] College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, 210003 China [2] Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province, Nanjing 210023, Jiangsu, China [3] Department of Electrical and Computer Engineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0407, USA.

ABSTRACT
In this paper, we prepared a novel structure to enhance the electroluminescence intensity from Si quantum dots/SiO2multilayers. An amorphous Si/SiO2 multilayer film was fabricated by plasma-enhanced chemical vapor deposition on a Pt nanoparticle (NP)-coated Si nanopillar array substrate. By thermal annealing, an embedded Si quantum dot (QDs)/SiO2 multilayer film was obtained. The result shows that electroluminescence intensity was significantly enhanced. And, the turn-on voltage of the luminescent device was reduced to 3 V. The enhancement of the light emission is due to the resonance coupling between the localized-surface-plasmon (LSP) of Pt NPs and the band-gap emission of Si QDs/SiO2 multilayers. The other factors were the improved absorption of excitation light and the increase of light extraction ratio by surface roughening structures. These excellent characteristics are promising for silicon-based light-emitting applications.

No MeSH data available.