Ordered Arrays of Dual-Diameter Nanopillars for Maximized Optical Absorption

Fan, Zhiyong; Kapadia, Rehan; Leu, Paul W.; Zhang, Xiaobo; Chueh, Yu‐Lun; Takei, Kuniharu; Yu, Kyoungsik; Jamshidi, Arash; Rathore, Asghar A.; Ruebusch, Daniel J.; Wu, M.C.; Javey, Ali

doi:10.1021/nl1010788

Cited by 276 publications

(251 citation statements)

References 26 publications

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“…Dual-layer nanopillars were formed by varying the dia meter of the template from 130 nm in the lower half of the pillar to 60 nm in the upper half of the pillar. The structure demonstrated 99% absorptance in the wavelength range of 300 -900 nm, far higher than the absorptance achieved when either 60 or 130 nm pillars were used alone [ 34 ].…”

Section: Mesostructuresmentioning

confidence: 76%

Nanostructures for photon management in solar cells

Narasimhan

Cui

2013

Nanophotonics

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Abstract:The concurrent development of high-performance materials, new device and system architectures, and nanofabrication processes has driven widespread research and development in the field of nanostructures for photon management in photovoltaics. The fundamental goals of photon management are to reduce incident light reflection, improve absorption, and tailor the optical properties of a device for use in different types of energy conversion systems. Nanostructures rely on a core set of phenomena to attain these goals, including gradation of the refractive index, coupling to waveguide modes through surface structuring, and modification of the photonic band structure of a device. In this review, we present recent developments in the field of nanostructures for photon management in solar cells with applications across different materials and system architectures. We focus both on theoretical and numerical studies and on progress in fabricating solar cells containing photonic nanostructures. We show that nanoscale light management structures have yielded real efficiency gains in many types of photovoltaic devices; however, we note that important work remains to ensure that improved optical performance does not come at the expense of poor electrical properties.

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Section: Mesostructuresmentioning

confidence: 76%

Nanostructures for photon management in solar cells

Narasimhan

Cui

2013

Nanophotonics

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“…[5][6][7][8] This study focuses on the light trapping properties of semiconductor nanowire arrays, which arise from their subwavelength features. Semiconductor nanowires and nanowire arrays can exhibit remarkable optical phenomena, such as reduced reflectance, [9][10][11] enhanced absorption, [12][13][14][15] and spectral selectivity, [16][17][18] which arise due to efficient coupling into discrete photonic modes. For individual nanowires, the photonic modes have been identified as leaky waveguide modes, 6,16 which are resonantly excited via illumination perpendicular to their axis.…”

Section: Introductionmentioning

confidence: 99%

Resonant absorption in semiconductor nanowires and nanowire arrays: Relating leaky waveguide modes to Bloch photonic crystal modes

Fountaine

Whitney

Atwater

2014

Journal of Applied Physics

105

107

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We present a unified framework for resonant absorption in periodic arrays of high index semiconductor nanowires that combines a leaky waveguide theory perspective and that of photonic crystals supporting Bloch modes, as array density transitions from sparse to dense. Full dispersion relations are calculated for each mode at varying illumination angles using the eigenvalue equation for leaky waveguide modes of an infinite dielectric cylinder. The dispersion relations along with symmetry arguments explain the selectivity of mode excitation and spectral red-shifting of absorption for illumination parallel to the nanowire axis in comparison to perpendicular illumination. Analysis of photonic crystal band dispersion for varying array density illustrates that the modes responsible for resonant nanowire absorption emerge from the leaky waveguide modes.

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“…In recent years, photonic phenomena in semiconductor nanowires have been the subject of great interest and intensive research effort, motivated by fundamental interest owing to their remarkable optical properties, including reduced reflectance [1][2][3], increased absorption [4][5][6][7], and spectral selectivity [8][9][10], and are also of considerable interest in applications to optoelectronic and photovoltaic devices. For next generation photovoltaics, arrays of semiconducting nanowires present an opportunity to reduce material usage and cost, while maintaining or improving optoelectronic performance relative to thin film or bulk materials.…”

Section: Introductionmentioning

confidence: 99%

Near-unity broadband absorption designs for semiconducting nanowire arrays via localized radial mode excitation

Fountaine

Kendall²,

Atwater³

2014

Opt. Express

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Abstract:We report design methods for achieving near-unity broadband light absorption in sparse nanowire arrays, illustrated by results for visible absorption in GaAs nanowires on Si substrates. Sparse (<5% fill fraction) nanowire arrays achieve near unity absorption at wire resonant wavelengths due to coupling into 'leaky' radial waveguide modes of individual wires and wire-wire scattering processes. From a detailed conceptual development of radial mode resonant absorption, we demonstrate two specific geometric design approaches to achieve near unity broadband light absorption in sparse nanowire arrays: (i) introducing multiple wire radii within a small unit cell array to increase the number of resonant wavelengths, yielding a 15% absorption enhancement relative to a uniform nanowire array and (ii) tapering of nanowires to introduce a continuum of diameters and thus resonant wavelengths excited within a single wire, yielding an 18% absorption enhancement over a uniform nanowire array.

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Ordered Arrays of Dual-Diameter Nanopillars for Maximized Optical Absorption

Cited by 276 publications

References 26 publications

Nanostructures for photon management in solar cells

Nanostructures for photon management in solar cells

Resonant absorption in semiconductor nanowires and nanowire arrays: Relating leaky waveguide modes to Bloch photonic crystal modes

Near-unity broadband absorption designs for semiconducting nanowire arrays via localized radial mode excitation

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