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Superior broadband antireflection from buried Mie resonator arrays for high-efficiency photovoltaics.

Zhong S, Zeng Y, Huang Z, Shen W - Sci Rep (2015)

Bottom Line: Establishing reliable and efficient antireflection structures is of crucial importance for realizing high-performance optoelectronic devices such as solar cells.We find that the buried Mie resonator arrays mainly play a role as a transparent antireflection structure and their antireflection effect is insensitive to the nanostructure height when higher than 150 nm, which are of prominent significance for photovoltaic applications in the reduction of photoexcited carrier recombination.We further optimally combine the buried Mie resonator arrays with micron-scale textures to maximize the utilization of photons, and thus have successfully achieved an independently certified efficiency of 18.47% for the nanostructured silicon solar cells on a large-size wafer (156 mm × 156 mm).

View Article: PubMed Central - PubMed

Affiliation: Institute of Solar Energy, and Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.

ABSTRACT
Establishing reliable and efficient antireflection structures is of crucial importance for realizing high-performance optoelectronic devices such as solar cells. In this study, we provide a design guideline for buried Mie resonator arrays, which is composed of silicon nanostructures atop a silicon substrate and buried by a dielectric film, to attain a superior antireflection effect over a broadband spectral range by gaining entirely new discoveries of their antireflection behaviors. We find that the buried Mie resonator arrays mainly play a role as a transparent antireflection structure and their antireflection effect is insensitive to the nanostructure height when higher than 150 nm, which are of prominent significance for photovoltaic applications in the reduction of photoexcited carrier recombination. We further optimally combine the buried Mie resonator arrays with micron-scale textures to maximize the utilization of photons, and thus have successfully achieved an independently certified efficiency of 18.47% for the nanostructured silicon solar cells on a large-size wafer (156 mm × 156 mm).

No MeSH data available.


(a) SEM image of the SiNPs fabricated by MACE method. (b) SEM image of the SiNx-layer-buried SiNPs. (c) Experimental reflectance for both the unburied and SiNx-layer-buried random SiNPs atop planar silicon surfaces. The thickness of the SiNx layer varies from 20 nm to 55 nm.
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f4: (a) SEM image of the SiNPs fabricated by MACE method. (b) SEM image of the SiNx-layer-buried SiNPs. (c) Experimental reflectance for both the unburied and SiNx-layer-buried random SiNPs atop planar silicon surfaces. The thickness of the SiNx layer varies from 20 nm to 55 nm.

Mentions: The antireflection mechanisms of the SiNx layer buried SiNP Mie resonator arrays have also been examined in experiments, exhibited in Figure 4. The SiNPs are formed on the planar silicon surface by the metal assisted chemical etching (MACE) method. An scanning electron microscopy (SEM) image shows that they are non-periodic with a height of about 350 nm (Figure 4a). Their surfaces are conformally coated with a SiNx layer via plasma enhanced chemical vapor deposition (PECVD), as shown in the Figure 4b, from which the thickness of the SiNx layer is also estimated. Figure 4c depicts the measured reflectance of both the SiNx-layer-buried (with different thickness) and the unburied SiNPs varying with the wavelength. Similar to the results by the FDTD calculation, the reflectance of the SiNx-layer-buried SiNPs is much lower than that of the pure SiNPs over a broad wavelength. Also, there are two reflectance dips for the SiNx-layer-buried SiNPs (guided by dashed lines), and the reflectance value of the dip at the short wavelength increases, while that at the long wavelength decreases as the thickness of the SiNx layer is increased from 30 to 55 nm. Likewise, we attribute these two reflectance dips to the modulated interference antireflection and the Mie resonance, respectively. When the thickness of the SiNx layer is 55 nm, both antireflection mechanisms function effectively, leading to a low reflectance over a broad wavelength and thus the lowest Rave (the Rave are 13.54%, 8.57%, 6.77%, 5.21% and 4.09% for the SiNPs without SiNx and with 20, 30, 40, 55 nm SiNx coating over the wavelength from 400 to 1100 nm, respectively). It should be noted that though the SiNPs are random in the experiment and their dimensions are not identical to that in the simulation, their antireflection behaviors with respect to the thickness of the SiNx layer are quite similar to the periodic arrays calculated by FDTD, demonstrating the validity of the explanation and universality of the antireflection effects.


Superior broadband antireflection from buried Mie resonator arrays for high-efficiency photovoltaics.

Zhong S, Zeng Y, Huang Z, Shen W - Sci Rep (2015)

(a) SEM image of the SiNPs fabricated by MACE method. (b) SEM image of the SiNx-layer-buried SiNPs. (c) Experimental reflectance for both the unburied and SiNx-layer-buried random SiNPs atop planar silicon surfaces. The thickness of the SiNx layer varies from 20 nm to 55 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4352919&req=5

f4: (a) SEM image of the SiNPs fabricated by MACE method. (b) SEM image of the SiNx-layer-buried SiNPs. (c) Experimental reflectance for both the unburied and SiNx-layer-buried random SiNPs atop planar silicon surfaces. The thickness of the SiNx layer varies from 20 nm to 55 nm.
Mentions: The antireflection mechanisms of the SiNx layer buried SiNP Mie resonator arrays have also been examined in experiments, exhibited in Figure 4. The SiNPs are formed on the planar silicon surface by the metal assisted chemical etching (MACE) method. An scanning electron microscopy (SEM) image shows that they are non-periodic with a height of about 350 nm (Figure 4a). Their surfaces are conformally coated with a SiNx layer via plasma enhanced chemical vapor deposition (PECVD), as shown in the Figure 4b, from which the thickness of the SiNx layer is also estimated. Figure 4c depicts the measured reflectance of both the SiNx-layer-buried (with different thickness) and the unburied SiNPs varying with the wavelength. Similar to the results by the FDTD calculation, the reflectance of the SiNx-layer-buried SiNPs is much lower than that of the pure SiNPs over a broad wavelength. Also, there are two reflectance dips for the SiNx-layer-buried SiNPs (guided by dashed lines), and the reflectance value of the dip at the short wavelength increases, while that at the long wavelength decreases as the thickness of the SiNx layer is increased from 30 to 55 nm. Likewise, we attribute these two reflectance dips to the modulated interference antireflection and the Mie resonance, respectively. When the thickness of the SiNx layer is 55 nm, both antireflection mechanisms function effectively, leading to a low reflectance over a broad wavelength and thus the lowest Rave (the Rave are 13.54%, 8.57%, 6.77%, 5.21% and 4.09% for the SiNPs without SiNx and with 20, 30, 40, 55 nm SiNx coating over the wavelength from 400 to 1100 nm, respectively). It should be noted that though the SiNPs are random in the experiment and their dimensions are not identical to that in the simulation, their antireflection behaviors with respect to the thickness of the SiNx layer are quite similar to the periodic arrays calculated by FDTD, demonstrating the validity of the explanation and universality of the antireflection effects.

Bottom Line: Establishing reliable and efficient antireflection structures is of crucial importance for realizing high-performance optoelectronic devices such as solar cells.We find that the buried Mie resonator arrays mainly play a role as a transparent antireflection structure and their antireflection effect is insensitive to the nanostructure height when higher than 150 nm, which are of prominent significance for photovoltaic applications in the reduction of photoexcited carrier recombination.We further optimally combine the buried Mie resonator arrays with micron-scale textures to maximize the utilization of photons, and thus have successfully achieved an independently certified efficiency of 18.47% for the nanostructured silicon solar cells on a large-size wafer (156 mm × 156 mm).

View Article: PubMed Central - PubMed

Affiliation: Institute of Solar Energy, and Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.

ABSTRACT
Establishing reliable and efficient antireflection structures is of crucial importance for realizing high-performance optoelectronic devices such as solar cells. In this study, we provide a design guideline for buried Mie resonator arrays, which is composed of silicon nanostructures atop a silicon substrate and buried by a dielectric film, to attain a superior antireflection effect over a broadband spectral range by gaining entirely new discoveries of their antireflection behaviors. We find that the buried Mie resonator arrays mainly play a role as a transparent antireflection structure and their antireflection effect is insensitive to the nanostructure height when higher than 150 nm, which are of prominent significance for photovoltaic applications in the reduction of photoexcited carrier recombination. We further optimally combine the buried Mie resonator arrays with micron-scale textures to maximize the utilization of photons, and thus have successfully achieved an independently certified efficiency of 18.47% for the nanostructured silicon solar cells on a large-size wafer (156 mm × 156 mm).

No MeSH data available.