Highly-ordered vertical Si nanowire/nanowall decorated solar cells

doi:10.1364/OE.19.023078

« Show journal navigation

Highly-ordered vertical Si nanowire/nanowall decorated solar cells

Jian Wang, Zhenhua Li, Navab Singh, and Sungjoo Lee »View Author Affiliations

Optics Express, Vol. 19, Issue 23, pp. 23078-23084 (2011)
http://dx.doi.org/10.1364/OE.19.023078

View Full Text Article

Acrobat PDF (1150 KB)

Journal Search
Article Lookup

Article Tools

Citations

Alert me when this article is cited
Export Citation/Save

Article Navigation

▸ Article Outline
– Abstract
1. Introduction
2. Experimental details
3. Results and discussion
4. Conclusion
– References and links

Article Tools
Full Text
Article Info
References
Cited By
Figures
Metrics
Download PDF

Viewing Equations in the
HTML Article

Optimal Viewing Recommendations

Full Text
Article Info
References (13)
Cited By
Figures (5)
Metrics

Abstract

Highly-ordered vertical nanowire and nanowall arrays are studied on Si solar cell surface. The nanowall textured solar cell is found to be more effective in reducing the overall optical reflectance, resulting in higher short circuit current (J_sc = 24.9 mA/cm²) over nanowire structured (J_sc = 23.3 mA/cm²) and planar (J_sc = 17.5 mA/cm²) solar cells. The extracted energy conversion efficiency (η) from planar solar cell is 7.1%, while nanowire/nanowall cells show efficiency of 8.2% and 6.3%, respectively. If corrected with series resistance (R_s), nanowall solar cell exhibits the highest η of 9.8% in this experiment. A careful study of the series resistance from different types of the nanostructures is also presented.

1. Introduction

Solar cells with surface decorated by nanostructures are being considered as one of the most promising candidates for low-cost high-efficiency photovoltaic device due to their improved light trapping behavior [1

L. Hu and G. Chen, “Analysis of optical absorption in silicon nanowire arrays for photovoltaic applications,” Nano Lett. 7(11), 3249–3252 (2007). [CrossRef] [PubMed]

–4

J. S. Li, H. Y. Yu, S. M. Wong, G. Zhang, G. Q. Lo, and D. L. Kwong, “Surface nanostructure optimization for solar energy harvesting in Si thin film based solar cells,” in 2009 IEEE International Electron Devices Meeting (IEDM) (IEEE, 2009), pp. 1–4.

] and promise for material cost reduction [5

L. Tsakalakos, J. Balch, J. Fronheiser, B. A. Korevaar, O. Sulima, and J. Rand, “Silicon nanowire solar cells,” Appl. Phys. Lett. 91(23), 233117 (2007). [CrossRef]

B. Tian, X. Zheng, T. J. Kempa, Y. Fang, N. Yu, G. Yu, J. Huang, and C. M. Lieber, “Coaxial silicon nanowires as solar cells and nanoelectronic power sources,” Nature 449(7164), 885–889 (2007). [CrossRef] [PubMed]

]. As a result, solar cells based on nanowires are intensively investigated [7

K. Peng, Y. Xu, Y. Wu, Y. Yan, S. T. Lee, and J. Zhu, “Aligned single-crystalline Si nanowire arrays for photovoltaic applications,” Small 1(11), 1062–1067 (2005). [CrossRef] [PubMed]

S. M. Wong, H. Y. Yu, J. S. Li, G. Zhang, G. Q. Lo, and D. L. Kwong, “Design high-efficiency Si nanopillar-array-textured thin-film solar cell,” IEEE Electron Device Lett. 31(4), 335–337 (2010). [CrossRef]

In this letter, we report our recent findings on solar cells decorated with two kinds of nanostructures, the nanowire and the nanowall. The nanowall array was demonstrated for its stronger physical strength and effective light trapping property. Comparisons between the nanowire and nanowall were made in terms of the spectrum reflectivity, the short circuit current (J_sc) (which indicates overall sunlight absorption and carrier collection) and energy conversion efficiency (η). Specifically, η of ~9.8% is deduced from the nanowall solar cell. Furthermore, a detailed study of the nanowire/nanowall solar cells’ series resistance is also presented for the first time. It is shown that a more conformal metal deposition approach is much desirable for a practical nanostructure-decorated solar cell.

2. Experimental details

Standard bulk Si wafer which is typical for CMOS fabrications was used for the proof-of-concept-demonstration solar cell fabrication. The schematic of the solar cell device is illustrated in Fig. 1 (a) . The process started on p-type (100) single-crystalline Silicon wafers with resistivity in the range of 6-9 Ω-cm. BF₂/1e15 cm⁻²/20 keV was implanted onto the wafer backside for effective back-surface field formation. Dopant activation was done by 1000 °C/5 sec rapid thermal anneal. After cleaning, the wafer front-side was patterned using standard KrF deep ultraviolet (DUV) lithography to create pillar and line/space patterns over large area (12 mm × 12 mm). Reactive ion etching was used to transfer the patterns into the silicon. After pattern transfer, we obtained 1.3-µm-tall nanowire array with wire diameter of 100 nm at a pitch of 400 nm (Fig. 1 (b)). The nanowall’s width/height was 100 nm/1.3 µm at a pitch of 360 nm (Fig. 1 (c)). The selection of the pitches was based on minimum resolution criteria as smaller pitch is more effective in suppressing reflections as confirmed by RSoft simulations. Pillar patterns used to define wires have poorer resolution than line/space patterns required for wall due to 2D diffraction and mechanical weakness in the photo resist. Therefore the wire pitch is larger than wall pitch. The TEM image of the Si nanowires is Fig. 1 (d). Figure 1 (e) is the zoom-in image of the Si surface showing smooth profile.

Fig. 1 (a) 3D schematic of the Si nanowire/nanowall solar cell featuring buried pn junction, and back surface field. (b) SEM image of Si nanowire array. (c) SEM image of Si nanowall array. The NWires/NWalls align well with each other leading to effective light trapping. nanowall array. (d) TEM image of Si nanowires showing nanowire length of 1.3 µm and diameter of 100 nm. (e) HRTEM image of Si Nanowire cross-section, showing smooth Si nanowire side wall after RIE. Single-crystalline lattice is also visible.

After nanowire/nanowall etch, the under-surface p-n junction was formed by tilted 20 keV/4e15 cm⁻² phosphorus implant. Tilt in the implant was to ensure the formation of junction below the wire/wall. Finally, Ti/Cu metal was sputtered on both sides of the wafer. Though in current process DUV lithography was used, a low cost fabrication technique can easily be adopted for the formation of nanowire and nanowall structures by different means, such as self-assembly [7

K. Peng, Y. Xu, Y. Wu, Y. Yan, S. T. Lee, and J. Zhu, “Aligned single-crystalline Si nanowire arrays for photovoltaic applications,” Small 1(11), 1062–1067 (2005). [CrossRef] [PubMed]

] or nano-imprint [9

L. Guo, “Recent progress in nanoimprint technology and its applications,” J. Phys. D Appl. Phys. 37(11), R123–R141 (2004). [CrossRef]

3. Results and discussion

Figure 2 shows the reflectance (R) spectrum of the samples measured by Shimadzu UV-3600 UV-VIS-NIR spectrophotometer. The red line is the reflectance spectrum measured on reference Si planar surface sample, which fits well with the standard data up to wavelength of ~1000nm. At the wavelength range beyond 1000nm, the measured reflectance rises due to transparency of the Silicon at near-infra-red (NIR) range and the reflectance of the materials at the back of the sample. In comparison, the surface textured by the nanowire/nanowall nanostructure shows largely suppressed reflectance, in agreement with earlier findings using nanowire decoration [2

L. Tsakalakos, J. Balch, J. Fronheiser, M. Y. Shih, S. F. LeBoeuf, M. Pietrzykowski, P. J. Codella, B. A. Korevaar, O. Sulima, J. Rand, A. Davuluru, and U. Rapol, “Strong broadband optical absorption in silicon nanowire films,” J. Nanophotonics 1(1), 013552 (2007). [CrossRef]

L. Tsakalakos, J. Balch, J. Fronheiser, B. A. Korevaar, O. Sulima, and J. Rand, “Silicon nanowire solar cells,” Appl. Phys. Lett. 91(23), 233117 (2007). [CrossRef]

K. Peng, Y. Xu, Y. Wu, Y. Yan, S. T. Lee, and J. Zhu, “Aligned single-crystalline Si nanowire arrays for photovoltaic applications,” Small 1(11), 1062–1067 (2005). [CrossRef] [PubMed]

Fig. 2 Reflectance spectra of Si planar surface, nanowires and nanowalls. The solar power spectrum under AM1.5 condition is also shown.

The minima of nanowire’s reflectance at ~550nm is due to the interference between light and nanostructure. The nanowall array sample shows even lower reflectance with respect to nanowire sample. It is well known that in diffraction grating-like structures, the zero-order transmission is inversely proportional to the pattern’s filling ratio [10

M. Born, E. Wolf, and A. Bhatia, Principles of Optics (Pergamon, Oxford, 1975).

]. In our case for nanowire, the filling ratio is ~4.9% and the nanowall pattern is ~28.6%. So much lower zero-order transmission from nanowall pattern is expected, since there is less light which transmits directly through the nanowall array and bounces back from the highly reflective bulk Si surface underneath. Therefore in nanowall array, higher percentage of the incoming light is diffracted to tilted propagation path where stronger interaction with the nanostructure takes place, leading to more absorption/trapping and less reflection [1

L. Hu and G. Chen, “Analysis of optical absorption in silicon nanowire arrays for photovoltaic applications,” Nano Lett. 7(11), 3249–3252 (2007). [CrossRef] [PubMed]

The overall reflectance of each sample was evaluated by the weighted average reflection (R_W) [11

B. S. Richards, “Single-material TiO₂ double-layer antireflection coatings,” Sol. Energy Mater. Sol. Cells 79(3), 369–390 (2003). [CrossRef]

] over the interested wavelength range from 300 nm to 1200 nm. The R_W of planar Si surface is estimated to be ~31.6%. On the other hand, nanowire textured surface is able to reduce the R_W to 14.5% due to the interaction of nanoscaled structure with light. Nanowall surface further reduces the R_W to 6.1%, showing more than 50% reduction in total solar power as compared to nanowire. Worth noticing is that the R_W of 6.1% from nanowall samples is lower than R_W=8.6% for a typical commercial TiO₂ single-layer antireflection (SLAR) coating [11

B. S. Richards, “Single-material TiO₂ double-layer antireflection coatings,” Sol. Energy Mater. Sol. Cells 79(3), 369–390 (2003). [CrossRef]

]. In comparison, optimized double-layer antireflection (DLAR) coatings on non-encapsulated silicon flat surface have R_W in the rage of 1.5–2.5% [12

J. Zhao and M. A. Green, “Optimized antireflection coatings for high-efficiency silicon solar cells,” IEEE Trans. Electron. Dev. 38(8), 1925–1934 (1991). [CrossRef]

The electrical performances of these nanostructure solar cells were also characterized by quantum efficiency measurement. The external quantum efficiency (EQE) spectra of the samples are shown in Fig. 3 (a) . Figure 3 (b) depicts the internal quantum efficiency (IQE) which is calculated from IEQ=EQE/(1-R). In Fig. 3 (b), one can see that the carrier collection efficiencies of the difference samples are close to each other, despite of the fact that there are RIE-formed nanostructures in the Si surface for nanowire, nanowall samples.

Fig. 3 (a) External quantum efficiency (EQE) and (b) internal quantum efficiency (IQE) of the solar cell samples.

Then the samples were placed under AM1.5G, 100 mW/cm² illumination using “SOLAR LIGHT” 16S-150-007 solar simulator. The measurement temperature was maintained at 25 °C. The I-V characteristics for planar, wire decorated and wall decorated devices, are plotted in Fig. 4 . As seen from the figure, the planar surface solar cell shows the lowest J_sc of ~17.5 mA/cm² as a result of high reflection from the surface. In comparison, nanowire and nanowall surface-textured solar cells demonstrate much enhanced J_sc of 23.3 mA/cm² and 24.9 mA/cm², respectively, which is consistent with their strong light trapping effect presented in Fig. 2.

Fig. 4 IV characteristics of solar cells under standard AM1.5 illumination for planar, nanowire, nanowall solar cells. J_sc(nanowall) > J_sc(nanowire) > J_sc(planar) is due to stronger light trapping and absorption.

As a closer examination, the percentage of the light absorption is also estimated. This is done by subtracting the weighted reflected light from 100%. Also since silicon is almost transparent at the wavelength larger than 1000nm, we also ignored the absorption at that wavelength range. Following the detailed equation,

A b s o r p t i o n % = 1 - \frac{\int_{λ \min}^{λ_{S i}} R (λ) N_{p h} (λ) d (λ)}{\int_{λ \min}^{λ \max} N_{p h} (λ) d (λ)} - \frac{\int_{λ_{S i}}^{λ \max} N_{p h} (λ) d (λ)}{\int_{λ \min}^{λ \max} N_{p h} (λ) d (λ)}

(1)

Where R(λ) is the wavelength dependent reflection, N_ph is the photon flux of the solar spectrum, λ_min = 300nm is the start of the measurement range, λ_max = 1200nm is the end of the measurement range and λ_Si = 1000nm is the wavelength beyond which silicon has ignorable light absorption, the absorbed light is calculated to be α(planar):α(nanowire):α(nanowall) = 55.7%:70.7%:76.2% = 1:1.27:1.37, where α is the total absorbed light percentage. On the other hand, J_sc(planar): J_sc(nanowire): J_sc(nanowall) = 17.5:23.3:24.9 = 1:1.33:1.42. Therefore, the ratio of the electrical current between the samples agrees with the optical spectrum data. This result also verifies that the carrier collection efficiencies of the difference samples are similar to each other.

The performances of the fabricated solar cells are summarized in Table 1 . Comparing to the η of 7.1% attained by the planar solar cell, high η of 8.2% achieved for the nanowire solar cell is an indication of the essential role of the nanostructure light trapping layer. Despite good J_sc, for the nanowall devices, the overall efficiency is 6.3%. It is mainly limited by relatively low fill factor (FF) of 47.9%.

Table 1 Summary of fabricated Si solar cells with planar, nanowire-textured and nanowall-textured surface

	Planar	NWire	NWall
RW	31.6%	14.5%	6.1%
JSC (mA/cm2)	17.5	23.3	24.9
VOC (mV)	550	560	528
Fill Factor (FF)	73.6%	62.8%	47.9%
Rs (Ω)	1.37	3.10	7.86
η	7.1%	8.2%	6.3%
η with Rs factored out	7.4%	9.5%	9.8%

To investigate the cause for the degraded FF, multiple light intensity IV characteristics was recorded and analyzed for all three types of devices following [13

D. Schroder and D. Meier, “Solar cell contact resistance—a review,” IEEE Trans. Electron. Dev. 31(5), 637–647 (1984). [CrossRef]

]; shown in Fig. 5 is the illustration of such for the solar cells. To extract the series resistance (R_s) of the device, one point is picked up on each curve at J_sc-∆I, where ∆I is a small arbitrary number. The slope of the line connecting all such points provides R_s, which is ~1.37 Ω-cm² for the planar solar cell as estimated in Fig. 5. Using the same method, R_s of 3.10 Ωcm² and 7.86 Ωcm² were extracted from the typical nanowire and nanowall solar cells, respectively.

Fig. 5 Multiple intensity IV characteristics of the planar surface, nanowire and nanowall solar cell. The illuminations are of arbitrary intensities.

The high value of R_s in our devices is due to the non-optimized metallization process. It is well known that metal sputter process is incapable of filling deep gap as in our case where the nanostructures are with high aspect ratio. This is especially true for the nanowall structure, which have an aspect ratio of ~5:1. Therefore, the contact between metal and Si is degraded and the R_s from the nanowall cells is the highest among the different samples. However, it should be noted that the R_s can readily be lowered to a typical value of less than 1 Ωcm² [13

D. Schroder and D. Meier, “Solar cell contact resistance—a review,” IEEE Trans. Electron. Dev. 31(5), 637–647 (1984). [CrossRef]

], upon process optimization by more conformal metallization method such as electroplating or atomic layer deposition. Assuming the impact of R_s is eliminated, high η of 9.5% and 9.8% can be obtained from the nanowire and nanowall devices, respectively (Table 1).

4. Conclusion

In Conclusion, we have studied highly-ordered vertical nanowire/nanowall arrays on Si solar cell surface. While the nanowire-array-based solar cells show reflectivity of ~13% and energy conversion efficiency (R_s corrected) of 9.5%, the nanowall array textured solar cell demonstrates much reduced reflectivity of 6% and a corrected η of 9.8%. Our results indicate that the nanowall array is a promising candidate for future photovoltaic applications with further improvements through sidewall junction.

References and links

1.	L. Hu and G. Chen, “Analysis of optical absorption in silicon nanowire arrays for photovoltaic applications,” Nano Lett. 7(11), 3249–3252 (2007). [CrossRef] [PubMed]
2.	L. Tsakalakos, J. Balch, J. Fronheiser, M. Y. Shih, S. F. LeBoeuf, M. Pietrzykowski, P. J. Codella, B. A. Korevaar, O. Sulima, J. Rand, A. Davuluru, and U. Rapol, “Strong broadband optical absorption in silicon nanowire films,” J. Nanophotonics 1(1), 013552 (2007). [CrossRef]
3.	R. A. Street, P. Qi, R. Lujan, and W. S. Wong, “Reflectivity of disordered silicon nanowires,” Appl. Phys. Lett. 93(16), 163109 (2008). [CrossRef]
4.	J. S. Li, H. Y. Yu, S. M. Wong, G. Zhang, G. Q. Lo, and D. L. Kwong, “Surface nanostructure optimization for solar energy harvesting in Si thin film based solar cells,” in 2009 IEEE International Electron Devices Meeting (IEDM) (IEEE, 2009), pp. 1–4.
5.	L. Tsakalakos, J. Balch, J. Fronheiser, B. A. Korevaar, O. Sulima, and J. Rand, “Silicon nanowire solar cells,” Appl. Phys. Lett. 91(23), 233117 (2007). [CrossRef]
6.	B. Tian, X. Zheng, T. J. Kempa, Y. Fang, N. Yu, G. Yu, J. Huang, and C. M. Lieber, “Coaxial silicon nanowires as solar cells and nanoelectronic power sources,” Nature 449(7164), 885–889 (2007). [CrossRef] [PubMed]
7.	K. Peng, Y. Xu, Y. Wu, Y. Yan, S. T. Lee, and J. Zhu, “Aligned single-crystalline Si nanowire arrays for photovoltaic applications,” Small 1(11), 1062–1067 (2005). [CrossRef] [PubMed]
8.	S. M. Wong, H. Y. Yu, J. S. Li, G. Zhang, G. Q. Lo, and D. L. Kwong, “Design high-efficiency Si nanopillar-array-textured thin-film solar cell,” IEEE Electron Device Lett. 31(4), 335–337 (2010). [CrossRef]
9.	L. Guo, “Recent progress in nanoimprint technology and its applications,” J. Phys. D Appl. Phys. 37(11), R123–R141 (2004). [CrossRef]
10.	M. Born, E. Wolf, and A. Bhatia, Principles of Optics (Pergamon, Oxford, 1975).
11.	B. S. Richards, “Single-material TiO₂ double-layer antireflection coatings,” Sol. Energy Mater. Sol. Cells 79(3), 369–390 (2003). [CrossRef]
12.	J. Zhao and M. A. Green, “Optimized antireflection coatings for high-efficiency silicon solar cells,” IEEE Trans. Electron. Dev. 38(8), 1925–1934 (1991). [CrossRef]
13.	D. Schroder and D. Meier, “Solar cell contact resistance—a review,” IEEE Trans. Electron. Dev. 31(5), 637–647 (1984). [CrossRef]

OCIS Codes
(250.0250) Optoelectronics : Optoelectronics
(350.6050) Other areas of optics : Solar energy

ToC Category:
Solar Energy

History
Original Manuscript: July 5, 2011
Revised Manuscript: August 21, 2011
Manuscript Accepted: September 20, 2011
Published: October 28, 2011

Citation
Jian Wang, Zhenhua Li, Navab Singh, and Sungjoo Lee, "Highly-ordered vertical Si nanowire/nanowall decorated solar cells," Opt. Express 19, 23078-23084 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-23-23078

Sort: Author | Year | Journal | Reset

References

L. Hu and G. Chen, “Analysis of optical absorption in silicon nanowire arrays for photovoltaic applications,” Nano Lett.7(11), 3249–3252 (2007). [CrossRef] [PubMed]
L. Tsakalakos, J. Balch, J. Fronheiser, M. Y. Shih, S. F. LeBoeuf, M. Pietrzykowski, P. J. Codella, B. A. Korevaar, O. Sulima, J. Rand, A. Davuluru, and U. Rapol, “Strong broadband optical absorption in silicon nanowire films,” J. Nanophotonics1(1), 013552 (2007). [CrossRef]
R. A. Street, P. Qi, R. Lujan, and W. S. Wong, “Reflectivity of disordered silicon nanowires,” Appl. Phys. Lett.93(16), 163109 (2008). [CrossRef]
J. S. Li, H. Y. Yu, S. M. Wong, G. Zhang, G. Q. Lo, and D. L. Kwong, “Surface nanostructure optimization for solar energy harvesting in Si thin film based solar cells,” in 2009 IEEE International Electron Devices Meeting (IEDM) (IEEE, 2009), pp. 1–4.
L. Tsakalakos, J. Balch, J. Fronheiser, B. A. Korevaar, O. Sulima, and J. Rand, “Silicon nanowire solar cells,” Appl. Phys. Lett.91(23), 233117 (2007). [CrossRef]
B. Tian, X. Zheng, T. J. Kempa, Y. Fang, N. Yu, G. Yu, J. Huang, and C. M. Lieber, “Coaxial silicon nanowires as solar cells and nanoelectronic power sources,” Nature449(7164), 885–889 (2007). [CrossRef] [PubMed]
K. Peng, Y. Xu, Y. Wu, Y. Yan, S. T. Lee, and J. Zhu, “Aligned single-crystalline Si nanowire arrays for photovoltaic applications,” Small1(11), 1062–1067 (2005). [CrossRef] [PubMed]
S. M. Wong, H. Y. Yu, J. S. Li, G. Zhang, G. Q. Lo, and D. L. Kwong, “Design high-efficiency Si nanopillar-array-textured thin-film solar cell,” IEEE Electron Device Lett.31(4), 335–337 (2010). [CrossRef]
L. Guo, “Recent progress in nanoimprint technology and its applications,” J. Phys. D Appl. Phys.37(11), R123–R141 (2004). [CrossRef]
M. Born, E. Wolf, and A. Bhatia, Principles of Optics (Pergamon, Oxford, 1975).
B. S. Richards, “Single-material TiO2 double-layer antireflection coatings,” Sol. Energy Mater. Sol. Cells79(3), 369–390 (2003). [CrossRef]
J. Zhao and M. A. Green, “Optimized antireflection coatings for high-efficiency silicon solar cells,” IEEE Trans. Electron. Dev.38(8), 1925–1934 (1991). [CrossRef]
D. Schroder and D. Meier, “Solar cell contact resistance—a review,” IEEE Trans. Electron. Dev.31(5), 637–647 (1984). [CrossRef]

Balch, J.
Chen, G.
Codella, P. J.
Davuluru, A.
Fang, Y.
Fronheiser, J.
Green, M. A.
Guo, L.
Hu, L.
Huang, J.
Kempa, T. J.
Korevaar, B. A.
Kwong, D. L.
LeBoeuf, S. F.
Lee, S. T.
Li, J. S.
Lieber, C. M.
Lo, G. Q.
Lujan, R.
Meier, D.
Peng, K.
Pietrzykowski, M.
Qi, P.
Rand, J.
Rapol, U.
Richards, B. S.
Schroder, D.
Shih, M. Y.
Street, R. A.
Sulima, O.
Tian, B.
Tsakalakos, L.
Wong, S. M.
Wong, W. S.
Wu, Y.
Xu, Y.
Yan, Y.
Yu, G.
Yu, H. Y.
Yu, N.
Zhang, G.
Zhao, J.
Zheng, X.
Zhu, J.

Appl. Phys. Lett.

R. A. Street, P. Qi, R. Lujan, and W. S. Wong, “Reflectivity of disordered silicon nanowires,” Appl. Phys. Lett.93(16), 163109 (2008). [CrossRef]
L. Tsakalakos, J. Balch, J. Fronheiser, B. A. Korevaar, O. Sulima, and J. Rand, “Silicon nanowire solar cells,” Appl. Phys. Lett.91(23), 233117 (2007). [CrossRef]

IEEE Electron Device Lett.

S. M. Wong, H. Y. Yu, J. S. Li, G. Zhang, G. Q. Lo, and D. L. Kwong, “Design high-efficiency Si nanopillar-array-textured thin-film solar cell,” IEEE Electron Device Lett.31(4), 335–337 (2010). [CrossRef]

IEEE Trans. Electron. Dev.

J. Zhao and M. A. Green, “Optimized antireflection coatings for high-efficiency silicon solar cells,” IEEE Trans. Electron. Dev.38(8), 1925–1934 (1991). [CrossRef]
D. Schroder and D. Meier, “Solar cell contact resistance—a review,” IEEE Trans. Electron. Dev.31(5), 637–647 (1984). [CrossRef]

J. Nanophotonics

L. Tsakalakos, J. Balch, J. Fronheiser, M. Y. Shih, S. F. LeBoeuf, M. Pietrzykowski, P. J. Codella, B. A. Korevaar, O. Sulima, J. Rand, A. Davuluru, and U. Rapol, “Strong broadband optical absorption in silicon nanowire films,” J. Nanophotonics1(1), 013552 (2007). [CrossRef]

J. Phys. D Appl. Phys.

L. Guo, “Recent progress in nanoimprint technology and its applications,” J. Phys. D Appl. Phys.37(11), R123–R141 (2004). [CrossRef]

Nano Lett.

L. Hu and G. Chen, “Analysis of optical absorption in silicon nanowire arrays for photovoltaic applications,” Nano Lett.7(11), 3249–3252 (2007). [CrossRef] [PubMed]

Nature

B. Tian, X. Zheng, T. J. Kempa, Y. Fang, N. Yu, G. Yu, J. Huang, and C. M. Lieber, “Coaxial silicon nanowires as solar cells and nanoelectronic power sources,” Nature449(7164), 885–889 (2007). [CrossRef] [PubMed]

Small

K. Peng, Y. Xu, Y. Wu, Y. Yan, S. T. Lee, and J. Zhu, “Aligned single-crystalline Si nanowire arrays for photovoltaic applications,” Small1(11), 1062–1067 (2005). [CrossRef] [PubMed]

Sol. Energy Mater. Sol. Cells

B. S. Richards, “Single-material TiO2 double-layer antireflection coatings,” Sol. Energy Mater. Sol. Cells79(3), 369–390 (2003). [CrossRef]

Other

M. Born, E. Wolf, and A. Bhatia, Principles of Optics (Pergamon, Oxford, 1975).
J. S. Li, H. Y. Yu, S. M. Wong, G. Zhang, G. Q. Lo, and D. L. Kwong, “Surface nanostructure optimization for solar energy harvesting in Si thin film based solar cells,” in 2009 IEEE International Electron Devices Meeting (IEDM) (IEEE, 2009), pp. 1–4.

2010, Wong, IEEE Electron Device Lett.
2008, Street, Appl. Phys. Lett.
2007, Tsakalakos, Appl. Phys. Lett.
2007, Tian, Nature
2007, Hu, Nano Lett.
2007, Tsakalakos, J. Nanophotonics
2005, Peng, Small
2004, Guo, J. Phys. D Appl. Phys.
2003, Richards, Sol. Energy Mater. Sol. Cells
1991, Zhao, IEEE Trans. Electron. Dev.
1984, Schroder, IEEE Trans. Electron. Dev.

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

Click here to see a list of articles that cite this paper