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Liu W, Wang Y, Guo X, Song J, Wang X, Yi Y. Light Trapping in Single Elliptical Silicon Nanowires. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:nano10112121. [PMID: 33113822 PMCID: PMC7692122 DOI: 10.3390/nano10112121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 06/11/2023]
Abstract
Light trapping in single nanowires (NWs) is of vital importance for photovoltaic applications. However, circular NWs (CNWs) can limit their light-trapping ability due to high geometrical symmetry. In this work, we present a detailed study of light trapping in single silicon NWs with an elliptical cross-section (ENWs). We demonstrate that the ENWs exhibit significantly enhanced light trapping compared with the CNWs, which can be ascribed to the symmetry-broken structure that can orthogonalize the direction of light illumination and the leaky mode resonances (LMRs). That is, the elliptical cross-section can simultaneously increase the light path length by increasing the vertical axis and reshape the LMR modes by decreasing the horizontal axis. We found that the light absorption can be engineered via tuning the horizontal and vertical axes, the photocurrent is significantly enhanced by 374.0% (150.3%, 74.1%) or 146.1% (61.0%, 35.3%) in comparison with that of the CNWs with the same diameter as the horizontal axis of 100 (200, 400) nm or the vertical axis of 1000 nm, respectively. This work advances our understanding of how to improve light trapping based on the symmetry breaking from the CNWs to ENWs and provides a rational way for designing high-efficiency single NW photovoltaic devices.
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Affiliation(s)
- Wenfu Liu
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian, Henan 463000, China; (Y.W.); (X.G.); (J.S.)
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA;
| | - Yinling Wang
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian, Henan 463000, China; (Y.W.); (X.G.); (J.S.)
| | - Xiaolei Guo
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian, Henan 463000, China; (Y.W.); (X.G.); (J.S.)
| | - Jun Song
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian, Henan 463000, China; (Y.W.); (X.G.); (J.S.)
| | - Xiao Wang
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA;
| | - Yasha Yi
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA;
- Energy Institute, University of Michigan, Ann Arbor, MI 48109, USA
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Liu W, Guo X, Xing S, Yao H, Wang Y, Bai L, Wang Q, Zhang L, Wu D, Zhang Y, Wang X, Yi Y. Off-Resonant Absorption Enhancement in Single Nanowires via Graded Dual-Shell Design. NANOMATERIALS 2020; 10:nano10091740. [PMID: 32887500 PMCID: PMC7559431 DOI: 10.3390/nano10091740] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 08/30/2020] [Accepted: 09/01/2020] [Indexed: 01/04/2023]
Abstract
Single nanowires (NWs) are of great importance for optoelectronic applications, especially solar cells serving as powering nanoscale devices. However, weak off-resonant absorption can limit its light-harvesting capability. Here, we propose a single NW coated with the graded-index dual shells (DSNW). We demonstrate that, with appropriate thickness and refractive index of the inner shell, the DSNW exhibits significantly enhanced light trapping compared with the bare NW (BNW) and the NW only coated with the outer shell (OSNW) and the inner shell (ISNW), which can be attributed to the optimal off-resonant absorption mode profiles due to the improved coupling between the reemitted light of the transition modes of the leak mode resonances of the Si core and the nanofocusing light from the dual shells with the graded refractive index. We found that the light absorption can be engineered via tuning the thickness and the refractive index of the inner shell, the photocurrent density is significantly enhanced by 134% (56%, 12%) in comparison with that of the BNW (OSNW, ISNW). This work advances our understanding of how to improve off-resonant absorption by applying graded dual-shell design and provides a new choice for designing high-efficiency single NW photovoltaic devices.
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Affiliation(s)
- Wenfu Liu
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA; (D.W.); (Y.Z.); (X.W.)
- Correspondence: (W.L.); (Y.Y.)
| | - Xiaolei Guo
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Shule Xing
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Haizi Yao
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Yinling Wang
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Liuyang Bai
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Qi Wang
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Liang Zhang
- School of Mechanical and Energy Engineering, Huanghuai University, Zhumadian 463000, Henan, China; (X.G.); (S.X.); (H.Y.); (Y.W.); (L.B.); (Q.W.); (L.Z.)
| | - Dachuan Wu
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA; (D.W.); (Y.Z.); (X.W.)
| | - Yuxiao Zhang
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA; (D.W.); (Y.Z.); (X.W.)
| | - Xiao Wang
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA; (D.W.); (Y.Z.); (X.W.)
| | - Yasha Yi
- Integrated Nano Optoelectronics Laboratory, University of Michigan, Dearborn, MI 48128, USA; (D.W.); (Y.Z.); (X.W.)
- Energy Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Correspondence: (W.L.); (Y.Y.)
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