| 1. |
- Anttu, Nicklas, et al.
(författare)
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Absorption of light in InP nanowire arrays
- 2014
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Ingår i: Nano Reseach. - : Springer Science and Business Media LLC. - 1998-0124 .- 1998-0000. ; 7:6, s. 816-823
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Tidskriftsartikel (refereegranskat)abstract
- An understanding of the absorption of light is essential for efficient photovoltaic and photodetection applications with III-V nanowire arrays. Here, we correlate experiments with modeling and verify experimentally the predicted absorption of light in InP nanowire arrays for varying nanowire diameter and length. We find that 2,000 nm long nanowires in a pitch of 400 nm can absorb 94% of the incident light with energy above the band gap and, as a consequence, light which in a simple ray-optics description would be travelling between the nanowires can be efficiently absorbed by the nanowires. Our measurements demonstrate that the absorption for long nanowires is limited by insertion reflection losses when light is coupled from the air top-region into the array. These reflection losses can be reduced by introducing a smaller diameter to the nanowire-part closest to the air top-region. For nanowire arrays with such a nanowire morphology modulation, we find that the absorptance increases monotonously with increasing diameter of the rest of the nanowire.
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| 2. |
- Wallentin, Jesper, et al.
(författare)
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InP Nanowire Array Solar Cells Achieving 13.8% Efficiency by Exceeding the Ray Optics Limit.
- 2013
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 339:6123, s. 1057-1060
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Tidskriftsartikel (refereegranskat)abstract
- Photovoltaics based on nanowire arrays could reduce cost and materials consumption compared to planar devices, but have exhibited low efficiency of light absorption and carrier collection. We fabricated a variety of millimeter-sized arrays of p-i-n doped InP nanowires and found that the nanowire diameter and the length of the top n-segment were critical for cell performance. Efficiencies up to 13.8% (comparable to the record planar InP cell) were achieved using resonant light trapping in 180-nanometer-diameter nanowires that only covered 12% of the surface. The share of sunlight converted into photocurrent (71%) was six times the limit in a simple ray optics description. Furthermore, the highest open circuit voltage of 0.906 volt exceeds that of its planar counterpart, despite about 30 times higher surface-to-volume ratio of the nanowire cell.
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